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[ES] Hoy en día es urgente la búsqueda de fuentes de proteína sostenibles y los insectos parecen ser una posible solución. Estos son alimentados de residuos y subproductos vegetales de la industria agroalimentaria, requieren poca superficie y agua y, además, apenas producen gases de efecto invernadero. En el presente trabajo se diseña y se lleva a cabo un experimento en el cual se evalúan tres dietas distintas basadas en subproductos para la cría del insecto Tenebrio molitor. Previamente a la puesta en marcha del experimento se formulan e igualan las dietas en contenido de proteína y agua. La dieta del primer grupo es salvado de trigo y agua, la del segundo grupo salvado de trigo y zanahoria desechada y la del tercer grupo salvado de trigo y bagazo de cerveza. Se realizan controles semanales con el fin de controlar la cantidad de alimento ingerida, la cantidad excretada, el peso unitario y la tasa de mortalidad. Finalmente, se estudia la digestibilidad de los distintos nutrientes. Se concluye que la dieta de zanahoria y agua es la que más favorece el desarrollo larvario y que los coeficientes de digestibilidad son bajos. Es necesaria más investigación con el fin de conocer a qué se deben estos valores bajos., [EN] Nowadays, the search for sustainable protein sources is urgent and insects seem to be a possible solution. They are fed with residues and vegetable by-products of the agri-food industry, require little surface and water and, in addition, hardly produce greenhouse gases. In the present work, an experiment is designed and carried out in which three different diets based on by-products for the breeding of the Tenebrio molitor insect are evaluated. Prior to the implementation of the experiment, diets are formulated and matched in protein and water content. The diet of the first group is wheat bran and water, that of the second group of wheat bran and discarded carrot and that of the third group of wheat bran and beer bagasse. Weekly checks are carried out in order to control the amount of food ingested, the amount excreted, the individual weight and the mortality rate. Finally, the digestibility of the different nutrients is studied. It is concluded that the carrot and water diet is the one that most favors larval development and that the digestibility coefficients are low. More research is needed in order to know what these low values are due to.

[ES] En el camino hacia la intensificación sostenible en ganadería, la nutrición de precisión debe asegurar una dieta lo más ajustada a las necesidades de los animales. Todo alimento que no sea aprovechado por el animal se elimina, produciendo pérdidas económicas y medioambientales. La proteína es uno de los nutrientes con mayor coste de la dieta y de los que causa mayores problemas en el medio ambiente. El objetivo de este trabajo es conocer la evolución de las pérdidas de aminoácidos en el cuerpo de pollos de engorde alimentados con una dieta libre de nitrógeno (N-free). Esta información es necesaria para determinar el momento adecuado para eutanasiar a los animales para determinar de forma precisa las necesidades netas de aminoácidos para mantenimiento. Definir con exactitud estas necesidades contribuirá a ampliar la información necesaria para diseñar una proteína 100% digestible y aprovechable para pollos de engorde. Este estudio se llevó acabo en el Centro de Investigación de Ciencia y Tecnología Animal (CITA) ubicado EN Segorbe (Castellón) y la Universitat Politècnica de València (UPV). Se utilizaron 25 pollos alimentados desde el primer día con un pienso comercial, durante 10 días. Transcurrido ese tiempo se realizó el pesaje e inicio de la dieta N-free ad libitum durante 7 días. Los días 0, 2, 4 y 7, se pesaron y sacrificaron 5 pollos cada día. Se determinó la materia seca, proteína bruta y aminoácidos en el cuerpo entero de cada animal, para el cálculo de las pérdidas de aminoácidos en el cuerpo cuando el animal recibe una dieta adecuada en energía. Los análisis determinaron que la dieta N-free provoca una disminución de la ingestión en comparación a la realizada por un pollo de esta estirpe de forma habitual. Además, se confirma que los aminoácidos limitantes en esta especie son la metionina, lisina, treonina, valina e isoleucina. Se pudo definir un punto de partida para la determinación de las necesidades netas de aminoácidos en la fase de mantenimiento, [EN] On the way to sustainable intensification in livestock farming, precision nutrition must ensure a diet that best suits the needs of the animals. Nutrients not used by the animal are eliminated, producing economic and environmental losses. Protein is one of the costliest nutrients in diets and is responsible for environmental problems. The objective of this work was to study the evolution of amino acid losses in the body of broilers fed a nitrogen-free diet (N-free). This information is necessary to determine the appropriate time to euthanize the animals to accurately determine the net amino acid requirements for maintenance. Accurately defining these needs will help to expand the information needed to design a 100% digestible and usable protein for broilers. This study was carried out at the Animal Science and Technology Research Center (CITA) located in Segorbe (Castellón) and the Polytechnic University of Valencia (UPV). For this experiment, a total of 25 chickens were used. These animals were fed a commercial diet for the first ten days after hatching. On day 10 the animals were weighed and then started the N-free ad libitum diet for 7 days. On days 0, 2, 4 and 7, 5 chickens were weighed and slaughtered. The dry matter, crude protein and amino acids in the entire body of each animal were determined to calculate the losses of amino acids in the body when the animal receives a diet with an adequate energy level. The chemical analysis determined that the N-free diet causes a decrease in ingestion compared to a chicken from the same breed fed with a commercial diet. Furthermore, it was corroborated that the limiting amino acids in this species are methionine, lysine, threonine, valine and isoleucine. Moreover, it was possible to define a starting point for the determination of net needs of amino acids in the maintenance phase, after two days of adaptation, between day 2 and 4 after being fed an N-free diet.

[ES] Para redefinir las necesidades nutricionales de los conejos seleccionados por velocidad de crecimiento, necesitamos conocer como la ratio PD/ED puede afectar a la deposición de energía, proteína y aminoácidos en el cuerpo de dichos animales. Con el fin de alcanzar ese objetivo, en el presente trabajo se utilizó el cuerpo vacío de 72 conejos de la línea paternal R previamente sacrificados, 23 de ellos a los 28 días y los 49 restantes, tras el periodo de engorde a los 63 días. De estos últimos, 26 conejos recibieron el pienso Baja, de baja relación PD/ED (10,7g/MJ) y los otros 23 recibieron el pienso Alta, de alta relación PD/ED (12,2 g/MJ). La técnica utilizada fue la de sacrificio comparativo, la cual permite conocer la diferencia en la composición corporal al principio y final del experimento. Los animales alimentados con la dieta Alta mostraron valores ligeramente mayores para el peso del cuerpo vacío y el balance de proteína, sin ser esta diferencia significativa respecto a los animales alimentados con la dieta Baja. No obstante, sí que se observó que los animales alimentados con la dieta Alta mostraron un mayor contenido en proteína en su cuerpo vacío a los 63 días de vida (+0,48 puntos porcentuales; P=0,0163) que aquellos animales alimentados con la dieta Baja, sin modificaciones significativas en el perfil de aminoácidos de su proteína corporal. Sin embargo, se observó que los animales alimentados con la dieta Alta mostraron una mayor retención de valina (+1,02 g de valina durante el engorde; P=0,0508) que aquellos alimentados con la dieta Baja. Con todo esto, la utilización en la dieta de un perfil de aminoácidos adecuado y una alta relación PD/ED ajustada a las necesidades de los conejos, podría permitir que estos animales pudieran expresar todo su potencial de crecimiento, a pesar de sus limitaciones en lo que se refiere a la deposición proteica., [EN] To redefine the nutritional needs of rabbits selected by growth rate, it is essential knowing how the PD / ED ratio can affect the deposition of energy, protein and amino acids in the body of these animals. To achieve this objective, the present work used the empty body of 72 previously slaughtered rabbits of the R paternal line, 23 of them at 28 days and the remaining 49, after the growing period at 63 days. Of the latter group, 26 rabbits received the Low feed, with a low PD / ED ratio (10.7g / MJ) and the other 23 received the High feed, with a high PD / ED ratio (12.2 g / MJ). The used technique was the comparative sacrifice, which allows knowing the difference in body composition at the beginning and end of the experiment. The animals fed the High diet showed slightly higher values for empty body weight and protein balance. However, this difference was not significant in respect of the animals fed the Low diet. Furthermore, it was observed that the animals fed the High diet showed a higher protein content in their empty body at 63 days of life (+0,48 percentage points; P = 0,0163) than those animals fed with the Low diet, with no significant changes in the amino acid profile of their body protein. However, it was observed that animals fed the High diet showed greater retention of valine (+1,02 g of valine during fattening; P = 0,0508) than those fed the Low diet. Ultimately, the use of an adequate amino acid profile and a high PD / ED ratio adjusted to the needs of rabbits could allow these animals to express their full growth potential, despite their limitations concerning protein deposition.

[EN] Two diets were designed to investigate the effect of the growth rate on amino acid requirements in growing rabbits: M diet (with medium levels of amino acids, following current nutritional recommendations for growing rabbits) and H diet (with high levels of lysine, sulphur amino acids and threonine compared with current nutritional recommendations). Performance, nutrient retention and digestibility (faecal and ileal) trials, as well as a choice-feeding test were conducted. We found no differences in animal performance, nutrient retention and digestibility parameters between diets, but the animals showed a preference for the M diet, expressed by a high intra-individual repeatability in preference. Our results provide useful information and nutrition tools to move towards precision protein nutrition in growing rabbits. As a consequence of the genetic selection process in growing rabbits, there are currently fast-growing animals exhibiting an average daily gain that may exceed 45 g/d. The protein requirements of these animals, namely amino acid requirements, may differ from animals with low growth rates. The objective of this work was to evaluate growth performance, the coefficient of total tract apparent digestibility (CTTAD), the apparent ileal digestibility (AID) of amino acids and nutrient retention of fast-growing rabbits when they had access to a diet with high levels of amino acids and/or a diet formulated with current nutritional recommendations in a choice-feeding trial. To this end, two diets were formulated: the M diet following current nutritional recommendations for growing rabbits (including 8.1, 5.8 and 6.9 g/kg dry matter (DM) of total lysine, sulphur amino acids and threonine, respectively) and the H diet with higher levels of total lysine, sulphur amino acids and threonine (9.4, 6.6 and 7.8 g/kg DM, respectively). A total of 220 weaned rabbits, from a paternal line selected for the growth rate, had free access to the M diet, the H diet or both (M

[EN] Simple Summary The aim of this work was to elucidate how the dietary inclusion of phytase, at a normal dose and overdosed, could affect the utilization of nutrients and performance in young laying hens. When a diet deficient in Ca and P was applied, the dietary inclusion of phytase at low doses (500 FTU/kg) led to an improvement in the digestive efficiency of P in the first weeks after introduction. However, when these deficient diets were maintained in the long term, laying hens improved their digestive utilization of both Ca and P, a higher dose of phytase (1000 FTU/kg) being required to achieve greater P availability. This overdosage also provided additional extraphosphoric advantages, slightly improving access to other nutrients and the feed conversion rate of the hens. A total of 192 laying hens were used to evaluate the effect of dietary mineral content and phytase dose on nutrient utilization, egg production and quality and bone mineralization of young laying hens. Four dietary treatments were studied: PC, positive control with no added phytase, 4.07% Ca and 0.61% P; NC, negative control with no added phytase, 2.97% Ca and 0.37% P; and P500 and P1000, where NC diet was supplemented with phytase at 500 and 1000 FTU/kg, respectively. Hens' performance and egg traits were controlled from 22 to 31 weeks of age. Coefficients of total tract apparent digestibility (CTTAD) of nutrients were determined at 25 and 31 weeks of age. Apparent ileal digestibility (AID) and blood content of Ca and P, as well as bone traits, were determined at 31 weeks of age. Ca and P retention was higher in birds on PC diet at 25 weeks, but not at 31 weeks of age compared to those on NC diet (p < 0.05). P1000 birds had the highest CTTAD values for dry and organic matter at both ages (p < 0.001). CTTAD of Ca was significantly higher in P1000 diet than in NC diet at 31 weeks of age (p < 0.001). Birds fed with P500 diet at 25 weeks of age and P1000 at 31 weeks of age showed higher CTTAD a

[EN] Variations in phosphorous (P) digestibility as a function of methodology, phosphate source, physicochemical characteristics and commercial source were evaluated in broilers. Three methodologies and two phosphates (monocalcium phosphate, MCP, and dicalcium phosphate, DCP) from three different commercial sources were used in two experiments. In the first experiment, MCP and DCP were incorporated into a P-deficient diet at two levels of inclusion and P digestibility was evaluated using three methodologies of the regression method (total excreta, marker in excreta and prececal digestibility). In the second experiment, variations in P digestibility of six phosphate sources (three MCP and three DCP) were evaluated using the total collection method. The P digestibility of MCP ranged from 75.2 to 87.4% and from 80.5 to 86.6% for DCP amongst methodologies (p > 0.05). Particle size, surface area, degree of crystallinity and impurities varied amongst commercial sources. The P digestibility of the three tested commercial sources of MCP was 79.6% (MCP1), 70.2% (MCP2) and 65.6% (MCP3); p > 0.05. The P digestibility of the three tested commercial sources of DCP was 80.1% (DCP1), 77.4% (DCP2) and 71.4% (DCP3); p > 0.05. The objective of this study was to compare the total tract (total excreta and marker) and prececal methodologies to determine phosphorus (P) digestibility and to evaluate its variation as a function of the physicochemical characteristics of the inorganic phosphate used (monocalcium, MCP and dicalcium, DCP) from different commercial sources. A total of 176 1-day-old male broilers were used in two digestibility experiments. In Experiment 1, one MCP and one DCP were incorporated in the basal diet at two levels. In Experiment 2, MCP and DCP from three commercial sources were incorporated to the basal diet at one level. Physicochemical characteristics of inorganic phosphates were examined, as well. Additionally, bone mineralization and growth performance traits were

[ES] En los últimos años se ha notado gran interés en el aprovechamiento de subproductos de origen agroindustrial en alimentación animal. Esto puede suponer una ventaja económica y medioambiental para el sector ganadero, incrementando su rentabilidad y sostenibilidad. El objetivo principal de este trabajo es desarrollar un modelo de gestión y aprovechamiento del alperujo en la alimentación del ganado vacuno extensivo, en las comarcas de L¿Alt y Baix Maestrat y Els Ports (provincia de Castellón), que permita implementar la utilización de este subproducto del olivo en la alimentación animal de la zona. Para ello, se han identificado las barreras técnico-sociales para la utilización del alperujo en alimentación animal en las comarcas objeto de estudio y se ha evaluado el su uso potencial mediante un análisis geoespacial de las explotaciones ganaderas y almazaras. Además, se ha caracterizado el valor nutricional de los alperujos de la zona y técnicas de conservación del alperujo mediante ensilado en combinación con hoja de olivo y pulpa cítrica. Finalmente, se proponen alternativas de aprovechamiento del alperujo de proximidad a través de una gestión individual y colectiva. Los resultados de este trabajo muestran que el potencial de uso del alperujo en alimentación de ganado vacuno de las comarcas L¿Alt y Baix Maestrat, y Els Ports es elevado; aunque la producción de alperujo esta deslocalizada respecto a las explotaciones y exige de su transporte. El alperujo estudiado presenta una composición nutricional rica en fibra, bajo contenido en proteína con una alta presencia de ácido oleico que lo hace adecuado para su inclusión en las dietas de vacuno extensivo. Por su composición, es posible ensilarlo durante 90 días, preferiblemente con hoja de olivo para reducir lixiviados. Respecto a las alternativas de gestión, la media del 30% del alperujo producido puede ser gestionado a una distancia de proximidad media de 20 km (combinación de radios 15, 20 y 25 km) para explotacio, [EN] In recent years there has been an apreciable interest in the utilization of the sub products of agro-industrial origin in animal feed. This can be an economic and environmental advantage for the livestock sector, thereby increasing its profitability and sustainability. The main objective of this project seeks to develop and apply a model of management of use of alperujo in the feeding of beef cattle; in the counties of L'Alt and Baix Maestrat and Els Ports (provinces of Castellón); which would allow to implement the use of the olive tree sub products in the animal feed of the area. For that reason, the technical-social barriers for the use of alperujo in animal feed have been identified in the counties under this study and this potential use has been evaluated through a geospatial analysis of the cattle farms and oil mills. Furthermore, the nutritional value and conservation techniques of the alperujo have been characterized by silage in combination with olive leaf and citrus pulp. Finally, alternatives are proposed for the use of local alperujo through individual and collective management. The results of this project indicate that the potential application of alperujo in feeding cattle in the Alt and Baix Maestrat counties, and Els Ports is high; although the alperujo production is delocalised with respect to the farms and requires its transport. The alperujo has a nutritional composition rich in fiber, low in protein with a high presence of oleic acid that makes it suitable for inclusion in beef diets. Due to its composition, it¿s possible to ensile it for 90 days, preferably with an olive leaf to reduce leachate. Regarding the management alternatives, an average of 30% can be managed at an average proximity distance of 20 km (combination of radii 15, 20 and 25 km) for farms less than 50 heads through individual management reaching a total of 46 farms (8% census). Medium-distance solutions (radii greater than 30 km) involve collective management between oil m

[EN] In recent decades, recommendations on dietary protein content have been considerably reduced, while fibre content has been increased. Under these conditions, an adequate dietary amino acid balance could be crucial to optimise feed efficiency. Plasma urea nitrogen (PUN) level could be a good indicator of an amino acid imbalance and its potential has already been studied in other species, but not yet in rabbits. The main objective of the present work was to detect the possible interest of PUN in pinpointing amino acid deficiencies in rabbits. Two experimental diets were formulated from the same basal mixture, following all the recommendations for growing rabbits, except lysine, whose content was variable, following current guidelines in diet P8.1 or lower from those in P4.4 (with 8.1 and 4.4 g/kg dry matter of lysine and with 757 and 411 mg of lysine per MJ of digestible energy). Three different trials were designed: one where the animals were fed ad libitum (AL) and two others in which fasting periods of 10 h were included; one where feeding was restored at 08:00 h (Fast8h) and the other at 18:00 h (Fast18h). A total of 72 three-way crossbred growing rabbits (24 animals for each trial in a split-plot trial) up to a total of 12 recordings were used. Blood samples were taken every 4 h in AL trial and every hour after refeeding up to a total of six controls, in trials Fast8h and Fast18h. The differences between balanced and unbalanced diets in lysine were highest (P<0.001) between 04:00 h and 12:00 h in animals fed ad libitum, and at 3 h after refeeding (21:00 h) in Fast18h. These results suggest that PUN could be an adequate indicator to detect deficiencies in amino acids in growing rabbitdiets.

[ES] El manejo de reproductoras en grupo o semigrupo, con objeto de mejorar su bienestar, proporciona solo un ligero enriquecimiento del comportamiento locomotor y social, y algunos resultados zootécnicos próximos pero estadísticamente inferiores a los obtenidos en jaula individual, sin conseguir así compensar los resultados negativos del método: mayor mortalidad de gazapos lactantes, estrés, agresividad, heridas y mortalidad de las madres, unido a la complejidad, tiempo y trabajo requeridos por este manejo. Enriquecer la jaula individual mediante plataforma no deteriora los resultados zootécnicos, permite incrementar la movilidad y el repertorio comportamental de las conejas (saltar, erguirse), aumentando además la superficie disponible, pero empeora la higiene y aumentan los problemas sanitarios (pododermatitis, fracturas). Reposapatas y elementos para roer, así como refinar el enriquecimiento en las jaulas estándar, parece una vía útil para mejorar el bienestar mientras se profundiza en la gestión de la respuesta agresiva, así como en la idoneidad y en el modelo de grupo en las reproductoras de carne., [EN] Continuous and part-time group housing systems have been tested to improve the welfare of reproducing rabbit does. Part-time group provides some improvements in locomotor and social behavior, some good reproductive results ¿still significantly lower than individual cages¿, without making up for its negative effects: higher kit mortality, rates of aggression, injured and does mortality, on top of the complexity, time and effort invested. The continuous group system increases more the aforementioned problems. Individual cages enriched by a platform have no negative effect on productive performances, provide more opportunities for movements and behavioral repertoire in does (jumping, stand up), increase space availability, but deteriorate hygiene and health (pododermatitis, fractures). Plastic footrests, gnawing blocks, have a positive impact on improving welfare in rabbits. In conclusion, refining the enrichment of standard cages seems a useful way to improve welfare while studying how to reduce aggression, as well as the suitability of the breeding group and the group model in the meat rabbit does.

[EN] Despite the enormous efforts made to achieve effective tools that fight against Staphylococcus aureus, the results have not been successful. This failure may be due to the absence of truly representative experimental models. To overcome this deficiency, the present work describes and immunologically characterizes the infection for 28 days, in an experimental low-dose (300 colony-forming units) intradermal model of infection in rabbits, which reproduces the characteristic staphylococcal abscess. Surprisingly, when mutant strains in the genes involved in virulence (J Delta agr, J Delta coa Delta vwb, J Delta hla, and J Delta psm alpha) were inoculated, no strong effect on the severity of lesions was observed, unlike other models that use high doses of bacteria. The inoculation of a human rabbitized (FdltB(r)) strain demonstrated its capacity to generate a similar inflammatory response to a wild-type rabbit strain and, therefore, validated this model for conducting these experimental studies with human strains. To conclude, this model proved reproducible and may be an option of choice to check both wild-type and mutant strains of different origins.

[EN] Genetic selection for feed efficiency has increased the growth rate and requirements of growing rabbits, while the protein content of commercial feeds has been adjusted to avoid digestive disorders. The aim of this work was to evaluate how a diet with moderate levels of protein content [146 g crude protein (CP)/kg] could be affecting protein and amino acids acquisition depending on the growth rate of the animals. From 189 weaned rabbits (28 days old), only 41 animals were selected at 42 days, in order to ensure the greatest variability for growth rate during fattening. To achieve this goal, animals came from three genetic lines: H and LP (maternal lines selected by litter size) and R (paternal line selected for growth rate), characterised by normal, moderate and high growth rate during the fattening period, respectively. Apparent faecal digestibility of dry matter (DM), CP and gross energy (GE) of the diet from 49-53 days of age, as well as the ileal apparent digestibility of DM, CP and amino acids at 63 days of age, was determined in all the selected animals. Protein, energy and amino acids retained in the empty body during the fattening period were also determined by slaughtering 15 weaning rabbits at 28 days, and the 41 selected animals at 63 days of age. Animals from the R line showed higher feed intake than those from maternal lines, as well as lower feed conversion ratio, even below that expected from their growth rate. Apparent faecal digestibility of GE and apparent ileal digestibility of DM, CP and cystine of the diet were higher in LP than in H rabbits (P < 0.05), showing intermediate values in R rabbits. However, apparent ileal digestibility of glutamic acid and glycine was significantly higher in R than in H rabbits (P < 0.05), showing intermediate values in LP rabbits. As expected, both daily protein and energy retained in the empty body increased as growth increased. However, R growing rabbits seem to have lower protein retained and higher energy

[EN] To assess the effect of increasing dietary lignin in isoenergetic diets at two soluble fibre (SF) levels on digestion, performance and carcass quality of growing rabbits, four diets were formulated according a 2 x 2 factorial design: low SF-low lignin (LSF/LL), low SF-high lignin (LSF/HL), high SF-low lignin (HSF/LL) and high SF-high lignin (HSF/HL). On average, in HSF diets SF was increased by 49 g/kg DM, mainly replacing starch ( - 53 g/kg DM), and in HL diets lignin was increased by 40 g/kg, mainly reducing starch (-78 g/kg DM), with increasing EE ( + 31 g/kg DM). Two hundred and sixty crossbred weaned rabbits (35 days old) were assigned to the experimental diets, individually housed and fed ad libitum until 63 days of age. Digestibility (from 49 to 53 days old), growth performance (from 35 to 63 days old), carcass quality (at 63 days old) and caecal environment (at 63 days old) were studied in 12, 65, 45 and 16 rabbits per diet, respectively. High SF diets showed higher CTTAD of fibrous fractions ( + 0.206 +/- 0.011, + 0.207 +/- 0.015, + 0.214 +/- 0.011 and + 0.167 +/- 0.015 for aNDFom, ADFom, hemicelluloses and cellulose, respectively, P < 0.001), OM ( + 0.042 +/- 0.004, P < 0.001) and GE ( + 0.055 +/- 0.005, P < 0.001), resulting in high DE content (10.6 vs. 9.30 MJ/kg DM). In contrast, CTTAD of CP was lower ( - 0.023 +/- 0.009, P = 0.013), as well as the DP content (96.9 vs. 103 g/kg DM). This dietary variation reduced the DM content of caecal digesta ( - 28 +/- 3 g/kg, P < 0.001), besides increasing its VFA concentration ( + 18.0 +/- 4.0 mmol/L, P < 0.001) and reducing its pH ( - 0.28 +/- 0.05, P < 0.001). Feed intake and LW gain decreased, with an improvement of feed to gain ratio ( -13.8 %, - 4.7 %, - 9.4 %, respectively; P < 0.001). The proportion of gastrointestinal tract was increased, with a subsequent reduction in dressing out ( + 19 +/- 2 g/kg LW and -15 +/- 2 g chilled carcass weight/kg LW, respectively, P < 0.001). High lignin diets showed low

[EN] The main purpose of this study was to find several early factors affecting stayability in rabbit females. To reach this goal, 203 females were used from their first artificial insemination to their sixth parturition. Throughout that period, 48 traits were recorded, considered to be performance, metabolic and immunological indicators. These traits were initially recorded in females' first reproductive cycle. Later, removed females due to death or culling and those that were non-removed were identified. A first analysis was used to explore whether it was possible to classify females between those reaching and those not reaching up to the mean lifespan of a rabbit female (the fifth reproductive) cycle using information from the first reproductive cycle. The analysis results showed that 97% of the non-removed females were classified correctly, whereas only 60% of the removed females were classified as animals to be removed. The reason for this difference lies in the model's characteristics, which was designed using early traits and was able to classify only the cases in which females would be removed due to performance, metabolic or immunologic imbalances in their early lives. Our results suggest that the model defines the necessary conditions, but not the sufficient ones, for females to remain alive in the herd. The aim of a second analysis was to find out the main early differences between the non-removed and removed females. The live weights records taken in the first cycle indicated that the females removed in their first cycle were lighter, while those removed in their second cycle were heavier with longer stayability (-203 and +202 g on average, respectively; P < 0.05). Non-removed females showed higher glucose and lower beta-hydroxybutyrate concentrations in the first cycle than the removed females (+4.8 and -10.7%, respectively; P < 0.05). The average lymphocytes B counts in the first cycle were 22.7% higher in the non-removed females group (P < 0.05). The

[EN] The main objective of this study was to evaluate the influence of pig's age on the effectiveness of a new microbial 3-phytase, produced by Komagataella phaffii, under commercial conditions in barley-wheat based diets. Two experiments were conducted in weaned, growing and finishing pigs; firstly, to determine phytase efficacy on dry matter, organic matter, energy, protein and mineral (phosphorus, P and calcium, Ca) digestibility (n = 48; Experiment 1), and secondly, to evaluate the effect of phytase on growth performance and bone mineralization (n = 312; Experiment 2). In each experiment, three barley-wheat based diets were formulated following the recommendations for each animal age, of which two versions were manufactured, including 0 and 1000 phytase units (FTU)/kg of feed of the new 3-phytase to be tested. Results showed the new phytase had the potential to increase the digestibility of Ca and P (on av. + 0.05 and +0.06, respectively; P < 0.01), especially P digestibility in growing pigs (+0.10; P < 0.001), consequently decreasing P and Ca excretion. Digestible energy (DE) of the diet increased with the addition of phytase in weaned pigs (+0.69 MJ/kg of dry matter (DM); P < 0.001). Dietary inclusion of new 3-phytase enhanced average daily gain from 46 to 94 days of age (+0.07 kg/d; P < 0.05) and decreased feed conversion ratio from 46 to 154 days of age (on av. -0.13; P < 0.05), although no significant effect was observed from 154 to 185 days of age. Addition of the new 3-phytase also promoted bone mineralization, increasing the weight of the bones (+3.99 and +3.64 g of tibia at 95 days and metacarpus at 100 days of age, respectively; P < 0.05) and the ash, Ca and P content in these bones (e.g. + 0.46 and +0.33 g of P in tibia at 95 days and metacarpus at 100 days of age, respectively; P < 0.001). In conclusion, pig age affected the efficacy of a new 3-phytase on P and Ca digestibility both in weaned and growing diets and DE content of the weaned diets, whic

[EN] Formulating diets to maximize nutrient harnessing has positive effects on performance and environment. In the case of growing rabbits, clues exist indicating that animals with high growth rate when consuming current diets show lower protein retention than expected, and it could be related to amino acid supply. The aim of this work is to find the amino acid combination (27 experimental diets: 3 levels of the 3 main limiting amino acids: lysine, sulphur amino acids, and threonine) that would minimize the nitrogen excretion in the bloodstream, a marker of the efficiency in the amino acid use This combination is a good candidate to be tested in order to improve performance and reduce pollution. A total of 27 experimental diets were formulated starting from the same basal mixture, with a moderate content of crude protein and digestible energy (155 g and 9.86 MJ/kg of digestible matter (DM), respectively, both estimated). The contents of lysine, sulphur amino acids and threonine were variable. The first one, close to the current recommendations (Medium, M; 8.1, 5.8 and 6.9 g/kg DM for lysine, sulphur amino acids and threonine, respectively), and two other levels were on average 15% higher (High, H; 9.4, 6.6 and 7.8 g/kg DM for lysine, sulphur amino acids and threonine, respectively) or lower (Low, L; 6.7, 4.9 and 5.7 g/kg DM for lysine, sulphur amino acids and threonine, respectively). Diets were named with three letters, indicating lysine, sulphur amino acids and threonine levels, respectively. In total, 918 weaned rabbits (28 days old) were used (34 per diet). At weaning, animals were fed ad libitum with a commercial diet until day 46, day 47 each collective cage was randomly switched to one experimental diet. At day 48, blood samples were collected at 08:00h then the animals were subjected to 10 h of fasting and a second blood sample was extracted at 21.00h. At 08:00h, Pasmatic urea nitrogen (PUN) was higher with the L level of lysine (p< 0.001), unaffected by the

[EN] A fenugreek seed gum, extracted fromTrigonella foenum-graecumseeds and rich in galactomannan, was chemically and physically characterised and its prebiotic potential for young rabbits was evaluated in vitro, both as pure fenugreek seed gum and when included up to 20 g/kg in rabbit diets rich in soluble and insoluble fibre. Fenugreek seed gum was resistant to pepsin and pancreatin digestion but was totally fermented by rabbit caecal bacteria. Fenugreek seed gum linear inclusion up to 20 g/kg in diets rich in soluble fibre has led to a reduction in the solubility of some nutrients during in vitro enzymatic phase and an increase in the fermented fraction. Fenugreek seed gum satisfies two essential conditions of a prebiotic: resistance to enzymatic digestion and being totally fermented by caecal bacteria. Some components of soluble fibre appear to have prebiotic effects that can contribute to improving digestive health in post-weaning rabbits. In this work, a fenugreek seed gum (FGS), extracted fromTrigonella foenum-graecumseeds and rich in galactomannan, was characterised. Both the pure FSG and ten substrates obtained by the inclusion of 0, 5, 10, 15 and 20 g/kg of FSG in diets rich in soluble (SF) and insoluble (IF) fibre were evaluated in vitro to determine FSG prebiotic potential for rabbit diets. FSG was rich in total sugars (630 g/kg dry matter), consisting entirely of galactose and mannose in a 1:1 ratio, and a moderate protein content (223 g/kg dry matter). Pure FSG was affected very little by in vitro digestion, as only 145 g/kg of the FSG was dissolved during the enzymatic phase. However, the linear inclusion of FSG up to 20 g/kg in growing rabbit feeds has led to a reduction in the solubility of some nutrients during in vitro enzymatic phase, especially in SF diets. Pure FSG not digested during the enzymatic phase almost completely disappeared during the in vitro fermentation phase, 984 g/kg of this indigestible fraction. However, although linear inclusi

[EN] In recent decades, concern about rabbit welfare and sustainability has increased. The housing system is a very important factor for animal welfare. However, information about how different available housing types for female rabbits affect their health status is scarce, but this is an important factor for their welfare. Hence, the objective of this study was to evaluate the health status of female rabbits in five common housing systems: three different single-housing systems with distinct available surfaces and heights; a single-housing system with a platform; a collective system. Female rabbits in the collective and platform cages had greater cortisol concentrations in hair than those in the single-housing system with no platform. Haptoglobin concentrations and kit mortality rates during lactation were greater for the collective-cage female rabbits. The collective group had more culled females and more lesions than in the other groups. The main reasons for culling in all the groups were reproduction problems and presence of abscesses, and the collective group of females was the most affected. In conclusion, it appears that keeping females together in collective systems negatively affects their health status and welfare, while single-housing systems imply lower kit mortality rates during lactation and cortisol concentrations, and fewer lesions in female rabbits.

[ES] El objetivo de este trabajo fue evaluar el efecto de un extracto vegetal sobre los parámetros zootécnicos (peso vivo, PV; consumo medio diario, CMD; ganancia media diaria, GMD; e índice de conversión, IC) y el recuento de ooquistes en pollos de engorde. Esta información permitirá evaluar la eficacia del extracto vegetal testado frente a la coccidiosis aviar y su contribución a la reducción del uso de antibióticos en avicultura. Para ello, se utilizaron 544 pollos de engorde de 1 día de vida que se alimentaron los primeros 21 días de vida con un pienso de iniciación y a partir del día 22 con un pienso de engorde hasta el final del estudio (42 días). Los animales se alojaron en 32 corrales con 17 animales/corral. Se utilizaron cuatro tratamientos que se asignaron a 8 corrales/tratamiento. Los tratamientos experimentales se diferenciaron por el coccidiostato incluido en el pienso (coccidiostato convencional o fitobiótico) y su dosis: tratamiento 1, T1 (pienso control sin coccidiostato añadido), tratamiento 2, T2 (pienso control con coccidiostato convencional), tratamiento 3, T3 (pienso control con extracto vegetal a dosis 1 kg/t tanto en el pienso de iniciación como de engorde) y tratamiento 4, T4 (pienso control con extracto vegetal a dosis 1 kg/t en el pienso de iniciación y a dosis 0,5 kg/t en el pienso de engorde). Durante toda la prueba, se controló el PV de los animales de forma individual los días 7, 21 y 42 de la prueba y el pienso consumido por el corral. Además, se tomó muestra de las heces por corral (días 21 y 42) y del ciego de un animal/corral (día 42) para el recuento de ooquistes. Durante la fase de iniciación (0-21 días), la inclusión del fitobiótico tendió a mejorar la GMD y el IC frente al programa convencional de coccidiostatos (T2), aunque no fue significativamente distinto de los rendimientos productivos respecto al control negativo sin coccidiostato añadido (T1). En la fase de engorde (22-42 días) y globalmente (0-42 días), la aplicación del, [EN] The aim of this work was to evaluate the effect of a plant extract on the zootechnical parameters (live weight, LW; average daily feed intake, ADFI; average daily gain, ADG; and feed conversion rate, FCR) and the oocyst count in broilers. This information will be useful to evaluate the efficacy of the plant extract tested against avian coccidiosis and its contribution to the reduction of antibiotic use in the poultry meat sector. For this purpose, 544 1-day-old broilers were used, which were fed with a starter feed during the first 21 days of life and with a fattening feed from day 22 until the end of the study (42 days). The animals were housed in 32 pens with 17 animals/pen. Four treatments were used, which were assigned to 8 pens/treatment. The experimental treatments were differentiated by the coccidiostat included (conventional coccidiostat or phytobiotic) and its dose: treatment 1, T1 (control feed without coccidiostat), treatment 2, T2 (control feed with conventional coccidiostat), treatment 3, T3 (control feed with plant extract at a dose of 1 kg/t both in the starter and fattening feed) and treatment 4, T4 (control feed with plant extract at a dose of 1 kg/t in the starter feed and at a dose of 0.5 kg/t in the fattening feed). Throughout the experiment, LW was monitored individually on days 7, 21 and 42 of the trial. On these days, feed consumed was determined per the pen. In addition, faeces were sampled from each pen (days 21 and 42) and from the cecum of one animal/pen (day 42) for oocyst counting. During the initiation phase (0-21 days), the inclusion of the phytobiotic tended to improve the ADG and FCR compared to the conventional coccidiostat program (T2), although it was not significantly different from the negative control without added coccidiostat (T1). In the fattening phase (22-42 days) and globally (0-42 days), the inclusion of the phytobiotic did not significantly change any of the productive variables compared to T1 and T2. There were no

[ES] El concepto de proteína ideal esta basado en la idea de que para alcanzar su rendimiento óptimo y máximo crecimiento en una determinada etapa vital las aves necesitan unas cantidades y ratios específicos de aminoácidos. Sin embargo, dichos aminoácidos deben obtenerlos de alimentos, cuya eficacia de utilización (proporción, digestión y metabolización) no es elevada, llevado a unas elevadas pérdidas de nitrógeno en las deyecciones. Lo ideal sería poder sintetizar una proteína que cubriera las necesidades de todos los aminoácidos (sin excesos, ni defectos) y que fuera totalmente digerida y metabolizada. El objetivo de este trabajo es desarrollar un proceso de diseño de una proteína ideal completamente digestible y aprovechable en pollos de engorde de 0 a 21 días. Para ello realizamos una investigación sobre los requerimientos netos de aminoácidos y el funcionamiento del sistema digestivo a nivel enzimático de los pollos de dicha edad. A partir de estos datos diseñamos posibles estructuras primarias del polipéptido. A continuación, predecimos su estructura terciaria y sus propiedades fisicoquímicas mediante métodos computacionales. Las proteínas obtenidas se valoran en base a su digestibilidad, características fisicoquímicas y proyecciones futuras de síntesis y producción. Este procedimiento es aplicable para la obtención de proteínas en otras etapas vitales del animal partiendo del conocimiento de las exigencias nutricionales específicas. El método secuencial planteado presenta una primera aproximación para el diseño de proteínas en alimentación de precisión y es susceptible de mejora e implementación con los avances en el campo de la lngeniería y Diseño de Proteínas., [EN] The ideal protein concept is based on the idea that to achieve optimum performance and maximum growth at a given stage of life, birds need specific amounts and ratios of amino acids. However, these amino acids must be obtained from feed, and their utilization efficiency (proportion, digestion and metabolization) is generally low, leading to high losses of nitrogen in excreta. Ideally, it should be possible to synthesise a protein that will meet the requirements of all amino acids (without excess or defect) while being fully digested and metabolised. The aim of this work was to develop a novel process to design an ideal protein completely digestible and usable in broilers from 0 to 21 days. To do so, we conducted a research on the net requirements of amino acids and the functioning of the digestive system at enzymatic level of chickens of that age. From these data, we designed possible primary structures of the polypeptide. Then, tertiary structure and its physicochemical properties were predicted by means of computational methods. The obtained proteins were evaluated based on their digestibility, physicochemical characteristics and future projections of synthesis and production. This procedure can be applied for obtaining proteins in other vital stages of the animal based on the knowledge of its specific nutritional requirements. The sequential method proposed presents a first approach for the design of proteins in precision feeding and is susceptible to improvement and implementation with progress in the field of Protein Engineering and Design.

[ES] Esta tesis aborda la caracterización y posible utilización de la goma de alholva (Trigonella foenum-graecum) (FSG, por sus siglas en inglés) en la nutrición de gazapos durante el período posterior al destete como una alternativa al uso de antimicrobianos, centrándose en el comportamiento de la goma extraída con diferentes niveles de fibra dietaria, tanto in vitro como in vivo. En el primer experimento, a partir de una dieta basal comercial de conejo, se formularon tres dietas experimentales con niveles graduales de inclusión de FSG (0, 0.25, 0.50%) administrados a tres grupos de conejos desde el destete a los 31 días hasta el sacrificio a los 94 días. Se estudió el efecto de las dietas experimentales sobre la digestibilidad fecal en dos edades (38-41 días y 56-59 días), además de los parámetros de fermentación cecal al final del experimento. Por otro lado, a partir de la misma dieta comercial de conejo, se formularon cinco dietas experimentales que contenían 0. 0.125, 0.25, 0.50 y 100% de FSG, que se sometieron a incubación in vitro con inóculo cecal de conejo durante 72 h. Se midieron la producción de gas y las variables de fermentación. La digestibilidad fecal aparente y los parámetros de fermentación cecal no se vieron afectados significativamente por la inclusión in vivo de FSG hasta 0.5%. Sin embargo, los animales alimentados con FSG mostraron valores de pH cecal más bajos. La inclusión gradual en la dieta de FSG aumentó la concentración in vitro de ácidos grasos volátiles (VFA, por sus siglas en inglés), mientras que el FSG puro aumentó la producción asintótica de gas y la tasa máxima de degradación del sustrato y disminuyó el tiempo de incubación en el que se forma la mitad de la cantidad asintótica de gas. La incubación in vitro de FSG puro disminuyó el valor del pH, la concentración de ácido láctico y la concentración de N-NH3, y aumentó la de VFA. En el segundo experimento, el FSG se caracterizó para determinar su composición química, su contenido de, [EN] This thesis tackles the possible characterisation and utilisation of fenugreek (Trigonella foenum-graecum) seed gum (FSG) in the nutrition of young rabbits during the post-weaning period as an alternative to antimicrobials uses. The study was focussed on the behaviour of the extracted gum with different dietary fibre levels, both in vitro and in vivo. In a first trial, starting from a basal commercial rabbit diet, three experimental diets were formulated with gradual levels of inclusion of FSG (0, 0.25, 0.50 %) given to three groups of rabbits starting from weaning at 31 days old to slaughter 94 days old. The effect of the experimental diets was studied on the faecal digestibility of the diet in two ages (38-41 days and 56-59days) and on the caecal fermentation parameters at the end of the experiment. On the other hand, starting from the same commercial rabbit diet five experimental diets were formulated containing 0, 0.125, 0.25, 0.50 and 100% of FSG that were submitted to in vitro incubation with rabbit caecal inoculum during 72h. Gas production and fermentation traits were measured. Apparent faecal digestibility and caecal fermentation parameters were not significantly affected by the in vivo inclusion of FSG up to 0.5%. However, animals fed with FSG showed lower caecal pH values. Gradual dietary inclusion of FSG increased in vitro concentration of volatile fatty acids (VFA), while pure FSG increased the asymptotic gas production and the maximum substrate degradation rate and decreased the time after incubation at which half of the asymptotic amount of gas is formed. In vitro incubation of pure FSG decreased pH value, lactic acid concentration and N-NH3 concentration and increased that of VFA. In a second trial, FSG was characterised determining its chemical composition, galactose and mannose content and prebiotic potential. Pure FSG and gradual levels of FSG (0, 5, 10, 15 and 20 g/kg), included both in diets rich in soluble fibre (SF) from beet pulp (includ, [CA] Aquesta tesi aborda la caracterització i possible utilització de la goma de fenigrec (Trigonella foenum-graecum) (FSG, per les sigles en anglès) en la nutrició del conills durant el període posterior al deslletament com una alternativa a l'ús d'antimicrobians, centrant-se en el comportament de la goma extreta amb diferents nivells de fibra dietària, tant in vitro com in vivo. En el primer experiment, a partir d'una dieta basal comercial de conill, es van formular tres dietes experimentals amb nivells graduals d'inclusió de FSG (0, 0.25, 0.50%) administrats a tres grups de conills des del deslletament als 31 dies fins al sacrifici als 94 dies. Es va estudiar l'efecte de les dietes experimentals sobre la digestibilitat fecal en dues edats (38-41 dies i 56-59 dies), a més dels paràmetres de fermentació cecal a la fi de l'experiment. D'altra banda, a partir de la mateixa dieta comercial de conill, es van formular cinq dietes experimentals que contenien 0. 0.125, 0.25, 0,50 i 100% de FSG, que es van sotmetre a incubació in vitro amb inòcul cecal de conill durant 72 h. Es van mesurar la producció de gas i les variables de fermentació. La digestibilitat fecal aparent i els paràmetres de fermentació cecal no es van veure afectats significativament per la inclusió in vivo de FSG fins a 0.5%. No obstant això, els animals alimentats amb FSG van mostrar valors de pH cecal més baixos. La inclusió gradual en la dieta de FSG va augmentar la concentració in vitro d'àcids grassos volàtils (VFA, per les sigles en anglès), mentre que el FSG pur va augmentar la producció asimptòtica de gas i la taxa màxima de degradació del substrat i va disminuir el temps d'incubació en el qual es forma la meitat de la quantitat asimptòtica de gas. La incubació in vitro d'FSG pur va disminuir el valor del pH, la concentració d'àcid làctic i la concentració de N-NH3, i va augmentar la de VFA. En el segon experiment, el FSG es va caracteritzar per determinar la seva composició química, el seu conti

[ES] Para poder establecer unas recomendaciones nutricionales más ajustadas para la relación proteína digestible (PD)/ energía digestible (ED), en conejos de engorde seleccionados por velocidad de crecimiento, se formularon y fabricaron dos piensos experimentales. El pienso B se formuló para tener la relación PD/ED habitualmente recomendada en los piensos para conejos de engorde (10,7 g/MJ) mientras que el pienso A se formuló para obtener una relación PD/ED más elevada (12,2 g/MJ). Se utilizaron en total 180 gazapos destetados (28 días de vida) de la línea paternal R de la Universidad Politécnica de Valencia, que se alojaron en jaulas individuales de forma equitativa entre ambos piensos, teniendo libre acceso al pienso correspondiente hasta los 63 días de vida. Los animales alimentados con el pienso A mostraron una mayor ingestión (+14±2 g de materia seca/d; P<0.001) y ganancia media diaria (+4.3±0.7 g/d; P<0.001) que el pienso B a lo largo de todo el cebo. Esto fue debido a que el pienso A tenía un mayor contenido proteico y se ajustó mejor a las necesidades, favoreciendo el crecimiento de estos animales. Sin embargo, los resultados relacionados con el índice de conversión de los animales alimentados con el pienso A, no fueron homogéneos a lo largo del cebo. Así, los animales cuando recibieron el pienso A mostraron un mejor índice de conversión durante la primera semana de engorde (0.10±0.03; P<0.05), mientras que éste fue mejor con el pienso B en las ultimas dos semanas de cebo (0.17±0.03; P<0.05). Esto fue probablemente debido a que las necesidades proteicas de los conejos de engorde disminuyen con la edad. Según los resultados obtenidos, la combinación correcta de estas dos relaciones de PD/ED, nos podría permitir optimizar el crecimiento y la eficiencia alimentaria en animales de alta velocidad de crecimiento., [EN] For this trial, two experimental diets were formulated and manufactured according to nutritional recommendations for digestible protein (PD)/digestible energy (ED) ratio, in fattening rabbits selected by growth rate. Diet B (low ratio PD/ED) was formulated to obtain the recommended PD/ED ratio of diets for fattening rabbits (10.7 g/MJ), while diet A (high ratio PD/ED) contained a higher ratio (12.2 g/MJ). A total of 180 weaned rabbits (28 days of life) of the paternal line R (Universitat Politècnica de València), were divided in two experimental groups (90 animals to each feed) and housed in individual cages, for 63 days. Animals fed with diet A showed a higher intake (+14±2 g dry matter/d; P<0.001) and average daily gain (+4.3±0.7 g/d; P<0.001) during the experimental period, than animals fed with diet B. Despite the diet A had a higher protein content, the nutritional requirements were fitted better and, consequently, their average daily gain was higher. However, the results related to the conversion rate of animals fed with diet A were not homogeneous along the weaning period. Thus, animals fed with diet A showed a lower conversion rate during the first week of fattening (0.10±0.03; P<0.05), while those fed with diet B showed better results in the last two weeks of the trial (0.17±0.03; P<0.05). Those results probably suggest that protein requirements for fattening rabbits decreased with the age. According to our results, an adequate combination of the two PD/ED ratio evaluated, could allow us to optimize the growth and the feed efficiency in rabbits selected by growth rate.

[ES] Se caracterizó la composición química de pulpas de remolacha granuladas, procedentes del norte y sur de España, cosechadas en invierno y verano, respectivamente. La composición química y el contenido de ácidos grasos y aminoácidos de 12 muestras de pulpa de remolacha se compararon agrupadas según su procedencia. Las pulpas de invierno y verano difirieron en el contenido en cenizas insolubles (P<0.05), fibra detergente neutro (P<0.05), fibra soluble en detergente neutro (P<0.01) y almidón (P<0.01). El contenido en proteína bruta y aminoácidos fue bajo, así como el de grasa, cuyos ácidos grasos más representativos fueron linoleíco, palmítico y oleico, y en ningún caso mostraron diferencias entre grupos. El análisis de los componentes principales indicó que la fibra soluble en detergente neutro y los componentes fibrosos insolubles (fibra detergente neutro y fibra detergente ácido) explican 61.6 % de la variabilidad en la composición de la pulpa de remolacha. Se concluye que la pulpa de remolacha procedente de la industria azucarera de España es un subproducto que aporta alto contenido de fibras, solubles como insolubles, aunque es importante tipificar la naturaleza química de estos componentes fibrosos, dada su variabilidad según el origen., [EN] The chemical composition of granulated beet pulps, from the north and south of Spain, harvested in winter and summer, respectively, was characterized. The chemical composition and the content of fatty acids and amino acids of 12 samples of beet pulp were compared grouped according to their origin. The winter and summer pulps differed in the content of insoluble ash (P <0.05), neutral detergent fiber (P <0.05), soluble fiber in neutral detergent (P <0.01) and starch (P <0.01). The content of crude protein and amino acids was low, as well as that of fat, whose most representative fatty acids were linoleic, palmitic and oleic, and in any case showed differences between groups. The analysis of the main components showed that the fiber soluble in neutral detergent and the insoluble fibrous components (neutral detergent fiber and acid detergent fiber) explain 61.6 % of the variability in the beet pulp composition. It is concluded that beet pulp from the sugar industry in Spain is a by-product that provides high fiber content, soluble as insoluble, although it is important to typify the chemical nature of these fibrous components, given their variability according to origin.

[EN] To determine the digestibility variability of beet pulps (BP) in the nutritional value of diets for fattening rabbits, the substitution of 20 % of a control feed with BP from five different origins was evaluated. Rabbits of 42 days of age and 1.49 ± 0.208 kg of weight were used, housed in individual cages and with ad libitum feeding. The digestibility of feed components was determined by the conventional in vivo method of total fecal collection. The digestibility of each of beet pulps was determined by the substitution method. There was no effect of the substitution of components of the control feed with 20 % of BP from different sources in the voluntary intake of rabbits (P> 0.05). The inclusion of BP in diets increases the digestibility of dry matter, organic matter, gross energy and all fibrous fractions, and decreases the digestibility of crude protein. However, the effect was more or less important depending on the origin of BP (P <0.05), especially on the digestibility of all fibrous fractions, being the BP collected in summer the one with the highest digestibility. The origin of the BP also affected its nutritional value, giving values of digestible energy between 11.8 and 14.5 MJ kg DM-1 and digestible protein between 3.8 and 6.6 %., [ES] Para determinar la variabilidad de la digestibilidad de la pulpa de remolacha (PR) en el valor nutritivo de dietas para conejos de ceba, se evaluó la sustitución de 20 % de un pienso control con PR de cinco orígenes distintos. Se utilizaron conejos de 42 días de edad y 1.49 ± 0.208 kg de peso, alojados en jaulas individuales y con alimentación ad libitum. La digestibilidad de los componentes de los piensos se determinó por el método convencional in vivo de recolección fecal total. La digestibilidad de cada una de las pulpas de remolacha se determinó mediante el método de sustitución. No se apreció efecto de la sustitución de componentes del pienso control por el 20 % de PR de diferentes procedencias en el consumo voluntario de los conejos (P> 0.05). La inclusión de PR en las dietas aumenta la digestibilidad de materia seca, materia orgánica, energía bruta y de todas las fracciones fibrosas, y disminuye la digestibilidad de la proteína bruta. Sin embargo, el efecto fue más o menos importante según la procedencia de las PR (P< 0.05), especialmente ene la digestibilidad de todas las fracciones fibrosas, siendo la PR que se recolecta en verano la de mayor digestibilidad. El origen de la PR también afectó su valor nutritivo, dando valores de energía digestible entre 11.8 y 14.5 MJ kg MS-1 y de proteína digestible entre 3.8 y 6.6 %.

[EN] Life history theory suggests that different body development dynamics may influence survival and future reproductive performance of organisms. The present work studied how these dynamics could influence seminal traits and lifespan of rabbit males selected for growth rate and intended for Al. To achieve this goal, a total of 550 rabbit males were controlled from birth, evaluated both during the testing phase (four consecutive weeks after reaching 147 days of life) and the productive phase (377 of them from the end of the testing phase until 2 years of life). In order to obtain individuals with different body development dynamics, we pre-selected males based on their live weight (LW) at 0, 28, 63 and 147 days and on their average daily gain (ADG) between each period (0-28, 28-63 and 63-147 days). Libido and main seminal traits (semen volume, motility, concentration, and production, as well as normal apical ridge and abnormalities of spermatozoa) were controlled during the testing phase. Semen volume, motility and concentration were subsequently controlled during the productive phase, as well as the length of the male life, calculated as the number of days a rabbit was present at the farm between age 147 and day of death, culling or censoring; set to 2 years of life). The birth weight, the ADG between 0 and 28 days and between 28 and 63 days were positively related to some seminal parameters measured during the testing phase (semen volume, concentration, production and motility; P<0.05), while the ADG between 63 and 147 days was negatively related to the seminal productivity throughout the productive life of the males (an increment of 10 g per day on ADG reduced the number of profitable ejaculates by 4.9%; P<0.05). In addition, a higher growth between 0 and 28 and between 63 and 147 days increased the risk of death or culling of males during the productive phase (P < 0.05). In conclusion, an adequate body development early in life seems to have a positive effect o

Tesis por compendio, [ES] Los estudios sobre nutrición proteica en conejos son escasos en comparación con otras especies, el cálculo de las necesidades es relativamente antiguo, no están ofrecidos a nivel ileal y sus peculiares hábitos alimenticios complican su conocimiento. Además, en los últimos años, se ha establecido relación directa entre este nutriente con una de las principales enfermedades que afectan esta especie (la Enteropatía Epizoótica del Conejo), y como consecuencia, el contenido proteico de las dietas se ha reducido. Por otro lado, se ha comprobado una pérdida en la efectividad de la selección por velocidad de crecimiento en las líneas paternales la cual podría estar relacionada con una mala estimación de los requerimientos proteicos (especialmente en los animales con elevadas velocidades de crecimiento). Finalmente, el nitrógeno ureico plasmático (PUN) podría ser una buena herramienta para estimar el grado de aprovechamiento proteico del pienso, pero su uso no ha sido comprobado aún en esta especie. Con todo ello, la principal hipótesis de esta tesis es que existe una mala estimación de las necesidades de aminoácidos en conejos con elevadas velocidades de crecimiento y que otra combinación de aminoácidos podría maximizar su rendimiento. Para evaluar esta hipótesis se utilizaron un total de 1464 conejos de engorde (provenientes principalmente de la línea R, línea paternal seleccionada por velocidad de crecimiento, y, en mucha menor medida, de líneas maternales con menores velocidades de crecimiento), se formularon un total de 32 dietas (donde principalmente diferían el contenido de los tres aminoácidos típicamente limitantes; lisina, aminoácidos azufrados y treonina), se realizaron 69 y 71 ensayos de digestibilidad fecal e ileal, respectivamente, se valoró la retención de nutrientes de 126 animales durante su crecimiento y por último se analizaron los niveles de PUN de más de 2700 muestras. Con el primero de los trabajos obtuvimos la confirmación del primer indicio: las, [CA] Els estudis sobre nutrició proteica en conills són escassos en comparació amb altres espècies, el càlcul de les necessitats és relativament antic, no estan oferts a nivell ileal i els seus peculiars hàbits alimentaris compliquen el seu coneixement. A més, en els últims anys, s'ha establert relació directa entre aquest nutrient amb una de les principals malalties que afecten aquesta espècie (la enteropatia epizoótica del Conill), i com a conseqüència, el contingut proteic de les dietes s'ha reduït. D'altra banda, s'ha comprovat una pèrdua en l'efectivitat de la selecció per velocitat de creixement en les línies paternals la qual podria estar relacionada amb una mala estimació dels requeriments proteics (especialment en els animals amb elevades velocitats de creixement). Finalment, el nitrogen ureic plasmàtic (PUN) podria ser una bona eina per estimar el grau d'aprofitament proteic del pinso, però el seu ús no ha estat comprovat encara en aquesta espècie. Amb tot això, la principal hipòtesi d'aquesta tesi és que hi ha una mala estimació de les necessitats d'aminoàcids en conills amb elevades velocitats de creixement i que una altra combinació d'aminoàcids podria maximitzar el seu rendiment. Per avaluar aquesta hipòtesi es van utilitzar un total de 1464 conills d'engreix (provinents principalment de la línia R, línia paternal seleccionada per velocitat de creixement, i, en molta menor mesura, de línies maternals amb menors velocitats de creixement), es van formular un total de 32 dietes (on principalment diferien el contingut dels tres aminoàcids típicament limitants; lisina, aminoàcids ensofrats i treonina), es van realitzar 69 i 71 assajos de digestibilitat fecal i ileal, respectivament, es va valorar la retenció denutrients de 126 animals durant el seu creixement i finalment es van analitzar els nivells de PUN de més de 2700 mostres. Amb el primer dels treballs vam obtenir la confirmació del primer indici: les dietes actuals semblaven presentar deficiències en, [EN] Studies on protein nutrition in rabbits are scarce compared with other species, the estimation of their requirements is relatively old and no data are reported at ileal level. Moreover, their peculiar feeding behaviour, including caecotrophy, complicates more this study. In addition, in recent years, a relationship has been established between dietary crude protein and Epizootic Rabbit Enteropathy (one of the most important disease that affects this species). As a consequence, the protein content of diets has been reduced. On the other hand, there has been a loss of effectiveness of the selection for growth rate in the paternal lines, which could be related with a possible nutritional deficit in high growth rate rabbits when using the current commercial diets. Plasma urea nitrogen (PUN) could be a good indicator of an amino acid imbalance, but its use has not yet been tested in rabbits. Thus, the main hypothesis of this thesis concerns that growing rabbits selected by growth rate could have amino acid requirements different from current recommendations, and that another amino acid combination would maximize productive traits. To evaluate this hypothesis, a total of 1464 growing rabbits were used (mainly from the R line, a paternal line selected by growth rate, and, to a much lesser extent, from some other maternal lines with lower growth rates), 32 diets were formulated differing in the content of the three typically limiting amino acids (lysine, sulfur amino acids and threonine). Faecal and ileal digestibility trials were performed with 69 and 71 animals, respectively. Nutrient retention during their growing period was evaluated in 126 animals. Finally, PUN was analyzed in more than 2700 samples. From the first trial,we obtained indication about the possible existence of some limiting amino acid when current moderate protein diets are used in growing rabbits with high growth rates, as retained protein to retained energy ratio was clearly lower for animals of t

[EN] To evaluate how rearing programmes could affect resources allocation and reproductive performance of primiparous rabbit females, a total of 118 rabbit females were used to evaluate the effects of five rearing feeding programmes on their performance from 1st to 2nd parturition: CAL, fed ad libitum C diet (11.0 MJ digestible energy (DE), 114 g digestible protein (DP) and 358 g NDF/kg dry matter (DM) until 1st parturition; CR, fed ad libitum with C diet until 12 weeks of age and then C diet restricted (140 g/day) until 1st parturition; F, fed ad libitum with F diet (8.7 MJ DE, 88 g DP and 476 NDF/kg DM) until 1st parturition; FC, fed with F diet ad libitum until 16 weeks of age, and C diet ad libitum until 1st parturition; FCF, fed with F diet ad libitum until 16 weeks of age, then C diet ad libitum until 20 weeks and then F diet ad libitum until 1st parturition. From 1st parturition, C diet was ad libitum offered to all the experimental groups until 2nd parturition. CAL females presented lower feed intake than females of F, FC and FCF groups in the 1st week of lactation (on av. ¿16.6%; P<0.05). During 1st lactation, the perirenal fat thickness change in CAL females was not different from 0 (+0.02 mm), while in the other four groups it increased (on av. +0.44 mm; P<0.05). Plasma of females fed with F diet during rearing (F, FC and FCF) had lower non-esterified fatty acids content than those exclusively fed with C diet (¿0.088 and ¿0.072 mmol/l compared to CAL and CR, respectively; P<0.05). FCF litters had higher weight than F litters at day 21 of lactation (+247 g; P<0.05), but FCF litter had significantly lower weight than FC litters at weaning (+170 g; P<0.05). CR females had the shortest average interval between the 1st and 2nd parturition (49 days) and FCF females the longest (+ 9 days compared to CR; P<0.05). At 2nd parturition, liveborn litters of F females were larger and heavier than litters of FCF females (+2.22 kits and +138 g; P<0.05), probably due to t

Tesis por compendio, [ES] Cualquier mejora en el conocimiento de la nutrición y el manejo de los futuros conejos reproductores debe considerarse como prioritario en la producción cunícola. Sin embargo, los principales esfuerzos en investigación se han centrado en estos animales durante la fase de reproducción propiamente dicha. La hipótesis inicial de esta tesis fue que alcanzar un desarrollo temprano adecuado durante la gestación, lactancia, engorde y recría, con la ayuda de programas ajustados de alimentación en algunos de estos períodos, mejoraría el rendimiento reproductivo y la vida útil de los futuros conejos reproductores. Para evaluar esta hipótesis, se llevaron a cabo dos tipos de ensayos, tanto en conejos hembra de líneas maternas como en machos de líneas seleccionadas por velocidad de crecimiento y destinadas a la inseminación artificial. El primero de estos ensayos se centró en los diferentes patrones de crecimiento, desde el nacimiento hasta el final de la fase de recría, y su influencia en la carrera reproductiva y la vida útil del conejo. En el segundo tipo de pruebas, se evaluó el efecto del uso de diferentes dietas o programas de alimentación durante el período de recría en la productividad a corto y medio plazo. Los resultados muestran dos fases importantes en el desarrollo temprano, de acuerdo con sus efectos sobre el rendimiento reproductivo y la vida útil. Mostrar un mayor desarrollo corporal desde el nacimiento hasta los 63 días de vida parece tener una influencia positiva en el grado de madurez y la productividad al comienzo de su vida reproductiva, además de poder mejorar su supervivencia a corto plazo, pero con posibles efectos negativos en la esperanza de vida a largo plazo. Sin embargo, el desarrollo durante el período de recría (desde los 63 días de vida hasta el comienzo de la carrera reproductiva) parece tener un mayor impacto en la productividad y la esperanza de vida de nuestros futuros conejos reproductores. Las hembras más engrasadas en la primera insem, [CA] Qualsevol millora en el coneixement tant de la nutrició com del maneig dels futurs conills de criança ha de considerar-se com a prioritari en la producció de conills. No obstant açò, els principals esforços en investigació s'han centrat en aquests animals durant la fase de reproducció pròpiament dita. La hipòtesi inicial d'aquesta tesi va ser que aconseguir un desenvolupament primerenc adequat durant la gestació, lactància, engreix i criança, amb l'ajuda de programes ajustats d'alimentació en alguns d'aquests períodes, milloraria el rendiment reproductiu i la vida útil dels futurs conills reproductors. Per a avaluar aquesta hipòtesi, es van dur a terme dos tipus d'assajos, tant en conills femella de línies maternes, com en mascles de línies seleccionades per a la velocitat de creixement i destinades a la inseminació artificial. El primer d'aquests assajos es va centrar en els diferents patrons de creixement, des del naixement fins al final de la fase de criança, i la seua influència en la carrera reproductiva i la vida útil del conill. En el segon tipus de proves, es va avaluar l'efecte de l'ús de diferents dietes o programes d'alimentació durant el període de criança, en la productivitat a curt i mig termini. Els resultats obtinguts semblen indicar que podríem diferenciar dues fases en el desenvolupament primerenc, d'acord amb els seus efectes sobre el rendiment reproductiu i la vida útil. Mostrar un major desenvolupament corporal des del naixement fins als 63 dies de vida sembla tenir una influència positiva en el grau de maduresa i la productivitat al començament de la seua vida reproductiva, a més de poder millorar la seua supervivència a curt termini, però amb possibles efectes negatius en l'esperança de vida a llarg termini. No obstant açò, el desenvolupament durant el període de sembla tenir un major impacte en la productivitat i l'esperança de vida dels nostres futurs conills reproductors. Les femelles més greixades en la primera inseminació van tenir g, [EN] Any improvement on the knowledge of both nutrition and management of the future rabbit breeders should be considered as crucial. However, main research efforts have been focused on animals during reproduction phase. The initial hypothesis of this thesis was that achieving an adequate early development during young rabbits' gestation, lactation, fattening and rearing, with the help of fitted feeding programmes in some of these periods, would be improved reproductive performance and lifespan of the future breeding rabbits. To evaluate this hypothesis, two types of trials, both in rabbit females from maternal lines selected for litter size at weaning and males from paternal lines selected for growth rate and intended on artificial insemination, were carried out. The first of these trials were mainly focused on the different growth patterns, from birth to the end of the rearing age, and their influence on rabbit's reproductive career and lifespan. In a second type of trials, the effect of the use of different diets or feeding programs during the rearing period in the performance in the short- medium-term was evaluated. The results obtained from the evaluation of the different growth patterns trials seem to indicate that, we could differentiate two parts on the early development according to their effects on reproductive performance and lifespan. To show a greater body development from birth to 63 days of life seems to have a positive influence on the maturity degree and productivity at the beginning of their reproductive life, as well as being able to improve their survival in the short-term, but it could be even negative for long-term lifespan. However, the development during the rearing period (from 63 days of life to the beginning of reproduction career) seems to have a higher impact on the productivity and lifespan of our rabbit breeders. Fatter rabbit females at first insemination had smaller litter sizes (born and weaned) and a higher risk of being culled (+1

[ES] El objetivo de este trabajo fue evaluar la eficacia de una nueva 3-fitasa en pollos de engorde de 1 y 21 días de vida; e identificar el efecto de la edad y de la duración del periodo de administración de la enzima en dietas deficientes en P sobre el aprovechamiento de los nutrientes y la mineralización ósea. Para ello se realizaron 2 experimentos con pollos de engorde machos (Ross) que consistieron en una prueba corta de digestibilidad y determinación de la mineralización ósea (Experimento 1; con animales de 21 días de edad y 17 días de duración) y otra larga de performance (rendimientos productivos) con ensayo de digestibilidad, determinación de la mineralización ósea y bioquímica en sangre (Experimento 2; con animales de 1 día de edad y 42 días de duración). Los piensos experimentales fueron: control positivo (C+): sin fitasa y con niveles comerciales de P, control negativo (C-): sin fitasa y con niveles bajos de P y Ca, tratamiento 250: C- + 250 FTU/kg, tratamiento 500: C- + 500 FTU/kg, tratamiento 1.000: C- + 1.000 FTU/kg y tratamiento 10.000: C- + 10.000 FTU/kg (como tratamiento de seguridad). Durante el estudio se realizó un balance de digestibilidad de Ca y P, de la materia seca (MS), materia orgánica (MO), proteína bruta (PB) y energía bruta (EB); se hizo un estudio de la mineralización ósea, y además se estudió parámetros bioquímicos en sangre y rendimientos productivos para el experimento 2. Los resultados demuestran la eficacia de la fitasa FLF1.000 sobre la digestibilidad de la MS, la PB, la MO, el Ca y el P a partir de la dosis 500 FTU/kg para ambos experimentos. Asimismo, se demostró la eficacia de la fitasa sobre la mineralización ósea por un aumento en la cantidad de cenizas y en la cantidad de minerales en tibia a partir de la dosis de 1.000 FTU/kg para ambos experimentos. Se observó un efecto relevante de la edad (periodo de administración de la fitasa) sobre todo en las variables de mineralización ósea, siendo mejor en los pollitos alimentado, [EN] The aim of this project was to evaluate the efficacy of a new 3-phytase in broilers of 1 and 21 days of life; and to identify the effect of age and the duration of the period of administration of the enzyme in P-deficient diets on the utilization of nutrients and bone mineralization. To do so, 2 experiments were carried out with male broiler chickens (Ross) that consisted of a short test of digestibility and determination of bone mineralization (Experiment 1, with animals 21 days of age and 17 days of duration) and another long performance with a digestibility test, determination of bone mineralization and blood biochemistry (Experiment 2, with animals of 1 day of age and 42 days of duration). The experimental feeds were: positive control (C +): without phytase and with commercial levels of P, negative control (C-): without phytase and with low levels of P (in experiment 1) low levels of P and Ca (in experiment 2) ), treatment 250: C- + 250 FTU / kg, treatment 500: C- + 500 FTU / kg, treatment 1,000: C- + 1,000 FTU / kg and treatment 10,000: C- + 10,000 FTU / kg (as a safety treatment) ). During the study, a digestibility balance of Ca and P, dry matter (DM), organic matter (OM), crude protein (CP) and gross energy (GE) was carried out; a study of bone mineralization was made, and biochemical parameters in blood and performance for experiment 2 were also studied. The results demonstrate the efficacy of phytase FLF1.000 on digestibility of MS, CP, OM, Ca and P from the dose 500 FTU / kg for both experiments. Likewise, the efficacy of phytase on bone mineralization was demonstrated by an increase in the amount of ash and in the amount of minerals in tibia from the dose of 1,000 FTU/kg for both experiments. A relevant effect of age (period of phytase administration) was observed, especially in the bone mineralization variables, being better in chicks fed with phytase from day 1 of life, compared with those fed from day 21. Finally, it was demonstrated that the phy

El objetivo es evaluar los efectos de incorporación en el pienso de cerdos en crecimiento, una nueva fitasa de origen bacteriano sobre el coeficiente de digestibilidad aparente y mineralización ósea en cerdos en crecimiento. Se utilizaron tres dietas experimentales que difieren en el nivel de incorporación de la fitasa. Se utilizarán 24 cerdos machos, en 2 tandas, cada tanda conformada por 12 cerdos. El periodo experimental tendrá una duración de 28 días, en cada tanda.

La reducción del contenido en proteína de los piensos de conejos, para reducir la incidencia de trastornos digestivos, puede estar limitando el desarrollo de los conejos pertenecientes a líneas de alta velocidad de crecimiento. En algunos trabajos previos hemos podido observar que para los tres primeros aminoácidos esenciales (lisina, aminoácidos azufrados y treonina) existen combinaciones que minimizan el nitrógeno ureico en plasma (PUN; indicador de un mejor ajuste de las necesidades para dichos animales). En el presente trabajo se realizará un estudio de digestibilidad fecal e ileal de tres piensos experimentales MMM (nivel actual de recomendaciones de lisina, aminoácidos azufrados y treonina), AAA (+15% de las actuales recomendaciones) y MAB (combinación que minimizaba PUN). Para ello utilizaremos un total de 95 conejos de engorde de la línea R, seleccionada por alta velocidad de crecimiento durante el engorde (28 a 63 d). Con dicho estudio podremos determinar las recomendaciones actuales para los animales de alta velocidad de crecimiento a nivel tanto fecal como ileal.

[EN] Genetic selection and nutrition management have played a central role in the development of commercial rabbitry industry over the last few decades, being able to affect productive and immunological traits of the animals. However, the implication of different energy sources in animals from diverse genetic lines achieving such evolutionary success remains still unknown. Therefore, in this work, 203 female rabbits housed and bred in the same conditions were used from their first artificial insemination until their fifth weaning. The animals belonged to three different genetic types diverging greatly on breeding goals (H line, hyper-prolific (n=66); LP line, robust (n=67) and R line, selected for growth rate (n=67), and were assigned to two experimental diets, promoting major differences in energy source (cereal starch or animal fat)). The aims of this work were to: (1) characterize and describe blood leucocyte populations of three lines of rabbit does in different physiological stages during their reproductive period: first artificial insemination, first weaning, second parturition and fifth weaning; and (2) study the possible influence of two different experimental diets on the leucocyte populations in peripheral blood. Flow cytometry analyses were performed on blood samples taken from females at each different sampling stade. Lymphocyte populations at both weanings were characterized by significantly lower counts of total, CD5(+) and CD8(+) lymphocytes (-19.8, -21.7 and -44.6%; P<0.05), and higher counts of monocytes and granulocytes (+49.2 and +26.2%; P<0.05) than in the other stages. Females had higher blood counts of lymphocytes B, CD8(+) and CD25(+) and lower counts of CD4(+) at first than at fifth weaning (+55.6, +85.8, +57.5, -14.5%; P<0.05). G/L ratio was higher at both weanings (P<0.05), and CD4(+)/CD8(+) ratio increased progressively from the 1AI to the 5 W (P<0.001). Regarding the effect of genetic type in blood leucocyte counts, LP animals presented t

El objetivo del presente estudio fue evaluar el efecto de enmascaramiento del sabor amargo, producido por la inclusión de aceites esenciales y antibióticos en el pienso de lechones en la fase de starter, sobre los parámetros zootécnicos [peso vivo (PV), consumo medio diario (CMD), ganancia media diaria (GMD) e índice de conversión (IC)], la severidad de diarreas y el comportamiento alimenticio. Se utilizaron 135 lechones [68 hembras y 67 machos, Pietrain x (Landrace x Large White)] con un PV medio de 6,9±1,29 kg y 35 días de edad al inicio del estudio. La duración del estudio fue de de 21 días. Los primeros 7 días, se administró un pienso común a todos los animales. Desde el día 8 al día 21 del experimento, se administraron los 3 piensos experimentales. Los animales se alojaron en corrales de 5 animales/corral. Se utilizaron 9 corrales por tratamiento. Los piensos experimentales consistieron en: Trat 1 (control negativo): dieta suplementada con 300 ppm de amoxicilina, aceites esenciales, ácidos orgánicos y ácidos grasos de cadena media; Trat 2 (control positivo): dieta de control negativo con aditivo sensorial validado, con sacarina sódica y neosperidina hydrochalcona a dosis legales para lechones en UE y de uso común en el sector; Trat 3 (alternativa sensorial): dieta de control negativo con con tecnología basada en la diversidad, sin sacarina ni neosperidina hydrochalcona. Los piensos se administraron en harina y ad libitum. Semanalmente, se realizó un control de peso individual. Además, diariamente, se registró el consumo de pienso por corral. Con esta información, se calculó la GMD, el CMD y el IC (g pienso/g peso). También se determinó la severidad de las diarreas aplicando una puntuación fecal diaria del día 8 al día 14 del estudio por corral. Finalmente, se realizaron observaciones de comportamiento alimenticio mediante grabaciones de vídeo de forma contínua, durante 10 minutos/día en cada corral los días 8 y 9 del estudio. A partir de esta información, se ev, Our objective was to evaluate the bitter-masking effect, produced by the inclusion of essential oils and antibiotics in piglet feed in the starter phase, on the zootechnical parameters [live weight (LW), average daily feed intake (ADFI), average daily gain (ADG) and feed conversion ratio (FCR)], incidence of diarrhea and feeding behavior. We used 135 piglets (68 females and 67 males, Pietrain x (Landrace x Large White)) with an average LW of 6.9 ± 1.29 kg and 35 days of age at the beginning of the study. The duration of the study was 21 days. The first 7 days, a wash-out feed was administered to all animals. From day 8 to day 21 of the experiment, the 3 experimental feeds were administered. The animals were housed in pens of 5 animals/pen. 9 replicate pens were used per treatment. The experimental feeds consisted of: Trat 1 (negative control): diet supplemented with 300 ppm of amoxicillin, essential oils, organic acids and medium chain fatty acids; Trat 2 (positive control): negative control diet with validated sensory additive, including sodium saccharin and hydrochalcone neosperidin at legal doses for piglets in the EU and commonly used in the sector; Trat 3 (sensory alternative): negative control diet with technology based on diversity, without saccharin or hydrochalcone neosperidin. Feed was administered in mash form and ad libitum. Animals were weighed individually every week. In addition, feed intake was daily recorded per pen. With this information, ADG, ADFI and FCR were calculated. The severity of diarrhea was also determined by applying a daily fecal score from day 8 to day 14 of the study. Finally, observations of feeding behavior were made through video recordings continuously, for 10 minutes/day in each pen; on days 8 and 9 of the study. The following variables were evaluated from video recordings: the number of feeding events in the feeding trough, the time eating in the feeding trough, the number of visits to the feeding trough without eating, the num

[ES] El presente estudio tiene como objetivo determinar el coeficiente de digestibilidad aparente del fósforo (P) y la mineralización ósea en pollos de engorde, de diferentes fuentes comerciales de P inorgánico, como el fosfato monocálcico (MCP) y el fosfato bicálcico (DCP), utilizando niveles subóptimos de incorporación. Se realizó un experimento con 176 pollos macho de 1 día de vida (40±5 g peso inicial; raza Ross 308), divididos en dos tandas de 88 animales cada una. La duración del estudio fue de 25 días. Durante los primeros 15 días los pollos estuvieron en un corral único y fueron alimentados con un pienso comercial. A partir del día 15, los animales se alojaron en jaulas de digestibilidad por parejas durante 10 días. Se utilizaron 7 fuentes comerciales de P: 3 MCP (MCP1 al MCP3) y 4 DCP (DCP1 al DCP4). Además, se utilizó un pienso basal pobre en P (Control) sin P añadido. Tres de los fosfatos (MCP1, DCP1 y DCP2), eran fuentes comerciales nuevas o en desarrollo, por lo que se testaron a 2 niveles cada uno (0,75 y 1,5 g/kg de P añadido procedente de cada fuente); mientras que el resto de fuentes (MCP2, MCP3, DCP3 y DCP4) se testaron a un solo nivel (1,5 g/kg de P añadido). La relación Ca:P se mantuvo constante e igual a 1,34. En total se utilizaron 11 tratamientos experimentales. En cada tanda se asignaron cada uno de los 11 tratamientos a 4 jaulas (8 réplicas al final del estudio para cada tratamiento). Los últimos 4 días del periodo en jaula se realizó un balance de digestibilidad para calcular el coeficiente de digestibilidad del P. El último día del estudio, se sacrificaron todos los animales y se extrajo la tibia izquierda para analizar las variables de mineralización ósea. Los resultados indicaron que respecto al MCP3 (que presentó un coeficiente de digestibilidad del P del 65,6%), las nuevas fuentes MCP1, DCP1 y DCP2 mostraron una tendencia a un mayor coeficiente de digestibilidad aparente del P (83,7, 80,3 y 79,8%, respectivamente; P<0,10). No se observ, [EN] The objective of this study was to determine the digestibility coefficient of phosphorus (P) and the bone mineralization in broilers using different commercial sources of inorganic P, such as monocalcium phosphate (MCP) and dicalcium phosphate (DCP), using suboptimal levels of incorporation. We used 176 one-day old male broilers (40 ± 5 g initial weight; Ross 308) divided into two batches of 88 animals per batch. The duration of the study was 25 days. During the first 15 days, broilers were housed in a single common pen and received commercial feed. From day 15, animals were housed in digestibility cages in pairs for 10 days. We used 7 commercial sources of P: 3 MCP (MCP1 to MCP3) and 4 DCP (DCP1 to DCP4). In addition, a basal diet poor in P (Control) without added P was used. Three of the phosphates (MCP1, DCP1 and DCP2) were new or developing commercial sources and were tested at 2 levels each (0.75 g / kg and 1.5 g / kg of added P from each source). The rest of the sources (MCP2, MCP3, DCP3 and DCP4) were tested at a single level (1.5 g / kg of added P). The Ca: P ratio remained constant and equal to 1.34. In total, 11 experimental treatments were used. In each batch, each of the 11 treatments was assigned to 4 cages (8 replications at the end of the study for each treatment). The last 4 days of the study, we conducted the digestibility balance to calculate the digestibility coefficient of the P. The last day of the study, all animals were slaughtered and the left tibia was extracted for analyses of bone mineralization variables. Results indicate that compared with MCP3 (showing a digestibility coefficient equal to 65.6%), the new sources MCP1, DCP1 and DCP2 showed a tendency to higher apparent digestibility of their P (83.7, 80.3 and 79.8%, respectively, P <0.10). No significant differences were observed amongst P sources in the evaluated bone mineralization variables. In conclusion, the new sources of P tested (MCP 1, DCP1 and DCP2) seem to improve the app

[EN] Factors influencing early development such as birth weight, nest competition, and the diet received during rearing have been proposed as elements conditioning the future reproductive performance of European rabbit (Oryctolagus cuniculus) females. To evaluate their effects, we followed the life of 1513 females from birth to time of death, culling or censoring (animals alive at a fixed date). Between 0 and 63 days of age 353 females died. From the remaining 1160 females, 864 were chosen based on their birth weight to be transferred from the selection to the production farm. At this farm, 431 females received the control diet (184g of CP, 381 g of NDF and 11.8 MJ of DE per kg DM), while the other 433 received the fibrous diet (134 g of CP, 436g of NDF and 10.0 MJ of DE per kg DM). Throughout the rearing period, we checked for the individual live weight and body condition (perirenal fat thickness) at first artificial insemination. Reproductive lifespan was defined as the number of days between the first parturition and the time of death, culling or censoring. Birth weight affected the survival of newborn females during lactation and the presence of a milk spot at birth (related to nest competition) increased the survivability of newborns weighing <45g (P <0.001). Rearing diet altered the growth curve of females and their body condition at first insemination. The diet also altered the relative risk of death during the rearing period, which was lower among females fed on the fibrous diet (-12.5%; P < 0.001). Therefore, a higher number of females fed with this diet reached their reproductive life, directly affecting the productivity measured per housed female. Fatter females at first insemination had smaller litter sizes and a higher risk of being culled than lean ones (P < 0.05). In general, the fibrous diet reduced the risk of leaving the herd at early rearing, and both birth weight and perirenal fat thickness affected female's reproductive lifespan. An excess of fa

[EN] The specialization process associated with genetic selection could be associated with functional disorders, affecting the reproductive success of females (fitness). We hypothesized that by modulating energy acquisition and allocation of females we could balance productivity and reproductive success. To test this hypothesis, we used 203 rabbit females belonging to three genetic types: H (n=66) maternal line specialized in prolificacy, LP (n=67) generalist maternal line, R (n=70) paternal line specialized in growth rate. We fed each genetic type with two diets specifically designed to promote milk yield (AF) or body reserves recovery (CS). We controlled females between their first and fifth reproductive cycles, recording traits related with productivity and fitness of females. H females fed CS had on average 11.2 +/- 0.43 kits with an individual weight of 54 +/- 1.2 g at birth and 525 +/- 11 g at weaning. Their conception rate when multiparous was 44% and their survival rate at the end of the experiment 30%. When they were fed AF, the individual weight of kits was 3.8 g heavier (P<0.05) at birth and 38 g heavier at weaning (P<0.05), the conception rate when multiparous increased 23 percentage points (P<0.05) and the survival rate at the end of the experiment 25 percentage points (P<0.05). LP females fed CS had on average 10.8 +/- 0.43 kits with an individual weight of 52 +/- 1.2 g at birth and 578 +/- 11 g at weaning. Their conception rate when multiparous was 79% and their survival rate at the end of the experiment 75%. When they were fed AF, it only increased individual weight of kits at weaning (+39 g; P<0.05). R females fed CS had on average 8.4 +/- 0.43 kits with an individual weight of 60 +/- 1.2 g at birth and 568 +/- 11 g at weaning. Their conception rate when multiparous was 60% and their survival rate at the end of the experiment 37%. When they were fed AF, they presented 1.4 kits less at birth (P<0.05) but heavier at birth (+4.9 g; P<0.05) and at weani

[EN] To achieve functional but also productive females, we hypothesised that it is possible to modulate acquisition and allocation of animals from different genetic types by varying the main energy source of the diet. To test this hypothesis, we used 203 rabbit females belonging to three genetic types: H (n=66), a maternal line characterised by hyper-prolificacy; LP (n=67), a maternal line characterised by functional hyper-longevity; R (n=79), a paternal line characterised by growth rate. Females were fed with two isoenergetic and isoprotein diets differing in energy source: animal fat (AF) enhancing milk yield; cereal starch (CS) promoting body reserves recovery. Feed intake, weight, perirenal fat thickness (PFT), milk yield and blood traits were controlled during five consecutive reproductive cycles (RCs). Females fed with CS presented higher PFT (+0.2 mm, P<0.05) and those fed AF had higher milk yield (+11.7%, P<0.05). However, the effect of energy source varied with the genetic type and time. For example, R females presented a decrease in PFT at late lactation (-4.3%; P<0.05) significantly higher than that observed for H and LP lines (on av. -0.1%; P>0.05), particularly for those fed with AF. Moreover, LP females fed with AF progressively increased PFT across the RC, whereas those fed with CS increased PFT during early lactation (+7.3%; P<0.05), but partially mobilised it during late lactation (-2.8%; P<0.05). Independently of the diet offered, LP females reached weaning with similar PFT. H females fed with either of the two diets followed a similar trajectory throughout the RC. For milk yield, the effect of energy source was almost constant during the whole experiment, except for the first RC of females from the maternal lines (H and LP). These females yielded +34.1% (P<0.05) when fed with CS during this period. Results from this work indicate that the resource acquisition capacity and allocation pattern of rabbit females is different for each genetic type. Mor

[ES] El principal objetivo de este trabajo fue evaluar el efecto sobre el coeficiente de digestibilidad aparente de la materia seca (MS), energía bruta (EB), proteína bruta (PB) y de las fracciones fibrosas, al variar la fuente de la fibra añadida a las dietas de futuras cerdas reproductoras. Para ello, se utilizaron 8 piensos en un diseño factorial 4x2 (4 tipos de fibra e inclusión o no de enzimas), aunque para este trabajo por cuestiones prácticas se considerará únicamente el efecto del tipo de fibra. Como fuentes de fibra, se utilizaron: fuentes de glucosa insoluble-celulosa (fórmula de base maíz con girasol y soja), fuentes de manosa (fórmula de base maíz con colza y palmiste), fuentes de glucanos (formula de base cebada con girasol y soja) y fuentes de arabinoxilanos solubles (fórmula de base trigo, salvado de arroz y germen de maíz con girasol y soja). Se utilizaron 12 cerdas vacías con un peso vivo inicial de 123,2±8,33 kg. Los animales se alojaron en jaulas de digestibilidad durante 8 periodos experimentales de 2 semanas de duración cada uno: 10 días de adaptación a los piensos experimentales y 4 días de recogida de muestras. Los animales se pesaron al inicio y final de cada periodo, y durante todo el periodo experimental se controló el consumo de pienso. Durante los 4 días de recogida el total de heces producidas se recogió y pesó cada 24 h. A partir de las muestras de pienso, se analizó la MS, cenizas, PB, extracto etéreo (EE), fibra bruta (FB), almidón (AL), la Fibra Neutro Detergente (FND), Fibra Ácido Detergente (FAD), Lignina (LAD), Fibra Dietaria Total (FDT), Fibra Dietaria Soluble (FDS), la proteína ligada a fibra y la EB. A partir de las muestras de heces individuales recogidas durante el balance de digestibilidad, se analizó la EB, MS y PB. A partir de un pool de heces por tratamiento, se realizaron las determinaciones de MS, EE, FND, FAD y FDT. No existieron diferencias significativas en el peso vivo y el consumo medio diario entre los diferentes, [EN] The main objective of this work was to evaluate the effect of the source of fiber on the apparent digestibility coefficients of dry matter (DM), gross energy (GE), crude protein (CP) and fiber fractions in future breeding sows. Eight dietary treatments in a 4x2 factorial design (four types of fiber and inclusion or not of enzymes) were used. For practical reasons in this research only the effect of fiber type was considered. As a source of fiber glucose insoluble-cellulose (corn, sunflower and soya diet), mannose (corn, rapeseed and palm kernel diet), glucan (barley, sunflower and soya diet) and arabinoxylans (wheat, rice brand and corn germ whit sunflower and soya) diets were tested. Twelve sows 123,2±8,33 kg initial live weight were used. The animals were housed in digestibility cages for eight experimental periods, two weeks each: ten days for experimental feed adaptation, and four days of feces collection. The animals were weighed at the beginning and at the end of each period. Throughout the whole experimental period, animal weight was controlled. During the 4 days of feces collection, the total amount of feces were collected and weighted each 24 hours. Feed samples were analyzed for DM, ash, CP, ether extract (EE), crude fiber, starch, neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin, total dietary fiber (TDF), soluble dietary fiber, the fiber-bound protein and GE. The individual sample feces collected were analyzed for DM, CP and GE. Feces were polled by treatment and each pool were analyzed for DM, EE, NDF, ADF and TDF, as well. No statistical significant differences were found in animal live weight and average daily consumption between treatments during the experimental period. The analyzed diet composition was similar to the estimated. There was a significant effect of the fiber type on DM, GE and CP (P<0.001) digestibility coefficients, in addition to EE, starch and fibers (NDF, ADF, gross fiber and TDF; P<0.05), being the latter ana, [CA] L’objectiu d’aquest treball es avaluar l’efecte sobre el coeficient de digestibilitat aparent de la matèria seca (MS), energia bruta (EB), proteïna bruta (PB) i de les fraccions fibroses, al variar les fonts de fibra en pinsos de porques reproductores. Per això, es van utilitzar 8 pinsos en un disseny factorial 4x2 (4 tipus de fibra e inclusió o no d’enzims), encara que per a aquest treball per qüestions pràctiques es considerarà únicament l’efecte del tipus de fibra. Com a fonts de fibra, es van utilitzar: fonts de glucosa insoluble-cel·lulosa (fórmula de base dacsa amb gira-sol i soja), fonts de manosa (fórmula de base dacsa amb colza i palmiste), fonts de glucans (fórmula de base d’ordi amb girasol i soja) y fonts d’arabinoxilans solubles (fórmula de base trigo, segó d’arròs i germen de dacsa amb gira-sol i soja). Es van utilitzar 12 porques buides amb un pes viu inicial de 123,2±8,33 kg. Els animals es van allotjar en gàbies de digestibilitat durant 8 períodes experimentals de 2 setmanes de duració cada u: 10 dies d’adaptació als pinsos experimentals i 4 dies de recollida de mostres. Els animals es pesaren a l’inici i al final de cada període i durant tot el període experimental es va controlar el consum de pinso. Durant els 4 dies de recollida el total de excrements produïts se va recollir i pesar cada 24 h. A partir de les mostres de pinso, s’analitzà la MS, cendres (cen), PB, extracte eteri (EE), fibra bruta (FB), midó (AL), la Fibra Neutra Detergent (FND), Fibra Àcid Detergent (FAD), Lignina (LAD), Fibra Dietaria Total (FDT), Fibra Dietaria Soluble (FDS) y la proteïna lligada a fibra. A partir de les mostres d’excrements individuals recollits durant el balanç de digestibilitat, s’analitzà la EB, MS i PB. A partir d’un pool d’excrements per tractament, es realitzaren les determinacions de MS, EE, FND, FAD i FDT. No van existir diferencies significatives en el pes viu i el consum medi diari (CMD) entre els diferents pinsos. La composició analitzada dels p

Tesis por compendio, During the last 50 years, there has been an overall improvement of efficiency in all domestic species thanks to an improvement in productivity traits. However, during the last years, disorders associated to a loss of functionality of animals (such as poor fertility, health and longevity of reproductive females) with high productivity standards have been observed. In this scenario, interactions between genetics and nutrition are becoming relevant. The main hypothesis of the present thesis is that nutritional strategies adapted to the genetic type could help to modulate productivity and functionality of females in the long term. To evaluate this hypothesis, 203 rabbit females were used which gave birth a total of 758 litters. These females belonged to 3 genetic types that differed greatly on their breeding goals: H, maternal line characterised by hyper-prolificacy; LP, maternal line characterised by functional hyper-longevity; R, paternal line characterised by growth rate. Females were fed during 5 consecutive reproductive cycles with 2 iso-energetic and iso-protein diets differing in energy source: Animal fat enhancing milk yield (84 g of ether extract per kg of DM and 105 g of starch per kg of DM); Cereal starch promoting body reserves recovery (21 g of ether extract per kg of DM and 237 g of starch per kg of DM). This experiment generated a set of longitudinal data with particular structures of (co)variances among data which had to be taken into account. Several models differing in the way data structure is modelled were evaluated. We found that none of the tested models was the best in terms of goodness of fit to the data for all traits, but it seems that models in which (co)variance structure was modelled in blocks of (co)variances for each reproductive cycle could be the most recommendable because they presented an overall suitable statistic performance (in terms of parsimony and fitting) and biological interpretation. These models provided useful information to, En los últimos 50 años, ha habido mejora general de la productividad y en consecuencia de la eficiencia en todas las especies domésticas. Sin embargo, en los últimos an¿os se han observado trastornos asociados a una pérdida de funcionalidad en animales con altos estándares de productividad (como baja fertilidad, salud o longevidad de las hembras reproductivas). Las interacciones entre la genética y la nutricio'n son cada vez ma's relevantes. La principal hipótesis de la presente tesis es que estrategias nutricionales adaptadas al tipo genético podrían ayudar a modular entre productividad y funcionalidad de las hembras. Para evaluar esta hipótesis, se utilizaron 203 conejas que dieron lugar a un total de 758 lactaciones. Estas conejas pertenecían a 3 tipos genéticos que diferían ampliamente en sus objetivos de selección: H, línea materna caracterizada por hiper-prolificidad; LP, línea materna caracterizada por hiper-longevidad funcional; R, línea paterna caracterizada por la velocidad de crecimiento. Las conejas fueron alimentadas durante 5 ciclos reproductivos consecutivos con 2 dietas iso-energéticas e iso-proteicas que diferían en la fuente de energía: Grasa animal para fomentar la producción de la leche (84 g de extracto etéreo por kg MS y 105 g de almidón por kg MS); Almidón de cereal para promover la recuperación de las reservas del corporales (21 g de extracto etéreo por kg MS y 237 g de almidón por kg MS). El experimento genero' una base de datos con datos longitudinales con unas estructuras particulares de (co)varianzas entre los datos y que debían tenerse en cuenta. En este sentido, se evaluaron varios modelos que diferían en la forma en que se modelan la estructura de datos. Se encontró que ninguno de los modelos probados fue el mejor en términos de bondad de ajuste para todos los caracteres. Sin embargo, parece que los modelos en los que la estructura (co) varianza se modelo' en bloques de (co)varianzas para cada ciclo reproductivo podrían ser los ma's re, En els últims 50 anys, ha aportat una millora general de la productivitat i, en conseqüència, de l'eficiència en totes les espècies domèstiques. Al llarg dels últims anys s'han observat trastorns associats a una pèrdua de funcionalitat en animals amb estàndards elevats de productivitat (com baixa fertilitat, salut o longevitat de les femelles reproductives). Les interaccions entre la genètica i la nutrició són cada vegada més rellevants. La hipòtesi principal de la tesi proposa que les estratègies nutricionals adaptades al tipus genètic permeten modular la productivitat i funcionalitat de les femelles. Per avaluar esta hipòtesi es van utilitzar 203 conilles que proporcionaren un total de 758 lactacions. Estes conilles pertanyien a tres tipus genètics que diferien àmpliament en els seus objectius de selecció: H, línia materna caracteritzada per hiperprolificitat; LP, línia materna caracteritzada per hiperlongevitat funcional; R, línia paterna caracteritzada per velocitat de creixement. A les conilles se'ls va subministrar 2 dietes isoenergètiques i isoproteiques durant cinc cicles reproductius consecutius, els quals diferien en la font d'energia: Greix animal per fomentar la producció de llet (84 g d'extracte eteri per kg MS i 105 g de midó per kg MS); Midó de cereal per promoure la recuperació de les reserves del corporals (21 g d'extracte eteri per kg MS i 237 g de midó per kg MS). L'experiment va generar una base de dades amb dades longitudinals amb unes estructures particulars de covariàncies entre les dades que havien de tindre's en compte. Es van avaluar diversos models que diferien en la forma en què modelitzaven l'estructura de les dades. Es va trobar que cap dels models provats va ser millor en termes de bondat d'ajust per a tots els caràcters. No obstant això, pareix que els models en què l'estructura covariància es va modelar en blocs de covariàncies per a cada cicle reproductiu podrien ser els més recomanables. Estos models van proporcionar informació úti

[ES] Optimización del contenido en aminoácidos limitantes en dietas de engorde de conejos en función de su velocidad de crecimiento., [EN] Nowadays, dietary protein level of fattening rabbits has been r educed to avoid frequent gastrointestinal problem s observed during this period and to minimize the environmental impact. This r eduction seems not be affecting commercial crossbred fattening rabbits, but those coming from lines highly selected for growth rate, seem to be not expressing all their genetic potential wit h under these conditions, widely affecting t he genetic rankings and consequen tly adequate genetic material diffusion. Theref ore, this thesis is an initia l attempt to determine the optimal levels of Lysine (Lys), sulphurous amino acid (Meth ionine and Cysteine) and Threonine (Thr) in function of growth rate of rab bits, through a matrix of 27 feeds and, using the Plasmatic Ureic Nitrogen (PUN ) level as a indicator of dietary amino acids imbalance. The study enrolled 432 rabbits, belonging to the R and V lines of Polytechnic University of Val encia, selected by growth rate and litter size, respectively. Each experimental fe ed was randomly assigned to each cage group of 8 rabbits, composed by animals f rom both genetic types, for a total of 27 cages per batch and two batches. The a verage daily gain (ADG) was significantly higher f or the R-line, and similarly, a verage PUN level on R line (16.43±0.19 mg/ dL; P<0.001) was greater that observed fo r the V-line (14.56±0.38 mg/dL; P<0.001). A po ssible explanation could be re lated to a greater amino acid imbalance on hi gh growth rate animals. As re gards differences on PUN level in function of dietary levels of Lys, sulphurous amino acid and Thr, average PUN reached the lowest levels for the med ium level of dietary Lys (7.3 g Lys/kg DM), as well as for the medium level of dietary sulphur amino acids (5.2 g Met/kg DM), as suggested by the literature. However, average PUN was reached the lowest level s only with the lowest dietary Thr level evaluated (5.3 g Thr/kg DM), per haps suggesting that current Th r recommendations (6.2 g Thr

[EN] In last decades, the protein content in feeds of growing rabbit has been reduced with the objective to decrease the risk of digestive disorders, minimize N excretion to environment and to optimize diets. Under these conditions, a correct amino acid formulation fee d could be crucial. This study evaluates the level of plasma urea nitrogen (PUN) as a possible indicator of amino acids deficit in growing rabbits. Two diets were formulated with 8.1 and 4.4 g of lysine per kg of dry matter, within the recommendations (P8. 1) and below them (P4.4), respectively. A total of 72 growing rabbits were used in three different trials : ad 2 libitum feeding ( Diario ) or complete restriction during ten hours, re - feeding at 08:00h (Rest8h) or 18:00h (Rest18h). A design with change was use d in the three trials , and feed intake between sampling was controlled. Blood was drawn from the central artery of the ear six times for each treatment (1mL using a catheter and stored in vials with ED TA), every four hours in Diario trial , and every hour s ince re - feeding in case of Rest8h and Rest18h trials . In trial Diario , changes in the level of PUN were associated to the previous intake, being both maximum at 20:00h (15.9 mg/dL and 10.9 g/d) and minimum at 8:00h (13.4 mg/dL and 4.8 g/d). Rabbits that we re fed with P4.4 had significantly lower feed intake (  21.4± 4.6 g/d; P<0.01) and higher level of PUN (+2.13± 26 mg/dL; P<0.001) than those fed with P8.1. Differences in PUN between diets were maximized at 04:00h to 12:00 (+2.63± 0 .67 mg/dL; P<0.001). In case of trial Rest8h, PUN data presented a higher variability probably due to caecotrophy interference . Finally in trial Rest18h, PUN data presented a lower variability, being the most significant difference between treatments at 21:00h. ( + 1.95±0.96 mg/dL; P=0 .0033). In conclusion, PUN determination 3 h after re - feeding at 21:00 could be consider as an adequate method to evaluate aminoacid imbalance in growing rabbits, [ES] Desarrollo y puesta a punto de un método para la determinación de la existencia de deficiencias en algún aminoácido a través del seguimiento de nitrógeno uréico en plasma (PUN) en conejos de engorde, para poder ser utilizado para determinar las necesidades en aminoácidos de los conejos de engorde en función de su velocidad de crecimiento., [CA] E n les últimes dècad es, el contingut proteic dels pinsos d'engreix ament en conills s'ha reduït per optimitzar les fórmules, minimitzar el risc de trastorns digestius, així com l'excreció de N a l'ambient. En aquestes circumstàncies, és fonamental el desenvolupament de mètodes que permetin avaluar el correcte ajust de cada aminoàcid de la dieta. El present treball tracta d’avaluar el nivell de Nitrò gen ureic plasmàtic (PUN) com un possible indicador del desequilibri aminoacídic en conills d'engreix ament. Per això es van formula r dues fabricacions de pinsos: un seguint les recomanacions amb 8.1 g de lisina per kg de matèria seca (P8.1) i un altre, deficitari, amb 4.4 g de lisina per kg de matèria seca (P4.4). Es van utilitzar un total de 72 conills en tres proves diferents: evolu ció diària amb alimentació ad libitum (Diari), i dos amb restricció total de l'aliment durant les 10 h prèvies a l'extracció de sang, un a restablint l'alimentació a les 08: 00h ( Rest8h) i l'altra a les 18:00 h (Rest18h). En totes elles es va realitzar un disseny experimental amb canvis , on es va controlar la ingestió. La sang va ser extreta, de l'artèria central de l'orella sis vegades per tractament (1 ml utilitzant un catèter i emmagatzemat en vials amb EDTA), pel cas del control diari cada 4 h, des de l es 08: 00h, i pel de les restriccions, cada h després del restabliment de l'alimentació. Pel que fa a l'evolució diària, el nivell de PUN va estar vinculat a la ingestió prèvia, tots dos màxims a les 20: 00h (15.9 mg / d L i 10.9 g / h) i mínims a les 8: 00 h (13.4 mg / dl i 4.8 g / h). Els conills alimentats amb el pinso P4.4 van presentar una ingesta significativament 3 menor ( - 21.4 ± 4.6 g / d; P <0.01) i un major nivell de PUN (+ 2.13 ± 26 mg / dl; P <0.001) que aquells alimentats amb un pinso P8.1, mostran t les majors diferències de PUN a les 08: 00h (+ 2.34 ± 0.52 mg / dL; P <0.001). En cas de Rest8h, es van obtenir dades per al PUN amb una major variabilitat (probabl

[EN] The aim of this study was to evaluate the efficacy of a new phytase produced by Pichia pastoris from a single gene of Serratia odorifera on performance (egg production, feed intake and feed conversion) and phosphorus utilization rates (P) and other nutrients determining the minimum of two new enzyme effective dose ages. Experiments were carried out with 240 hens Lohmann Brown line 16 weeks of life. These hens were assigned to five experimental treatments consisting on a control diet and four experimental diets that differed in the levels of the new enzyme (phytase units were assigned (UFT) / kg feed). The treatments were: C (control, without phytase and low P), 250 (C-250 UFT / kg feed), 500 (C-500 UFT / kg feed), 1000 (C- with 1000 UFT / kg feed) and 10,000 (10,000 C- UFT / kg feed). During the experiment a nutrient balance (fecal level) at 25 weeks of age and another nutrient balance (fecal and ileal level) at 30 weeks of age was performed. Thus the utilization ratio of calcium (Ca) and P, dry matter (DM), organic matter (OM), protein (CP) and energy (EB) was calculated. In addition, egg production and feed conversion (IT) and the average daily feed intake (CMD) were studied. No significant differences with the addition of phytase in the performance parameters (weight of animal, CMD, egg production, egg weight, mass and IT) relative to negative control were observed. With 25 week old hens, the addition of phytase improved (P <0.05) the rate of use of MS with 1,000 UFT / kg, the coefficient of digestibility of OM, CP and Ca 250 UFT / kg and the P 500 UFT / kg based on feed without phytase. With 30 week old hens, the addition of phytase improved (P <0.05) coefficient for DM, OM and P 1,000 UFT / kg and the coefficient of digestibility of Ca 10,000 UFT / kg compared to the feed without phytase. Adding 500 UFT / kg improved retention of Ca and P in 25 week old hens. Adding 1,000 UFT / kg improved retention of P in 30 week old hens. Mineral excretion was not signi, [ES] El objetivo del presente estudio fue evaluar la eficacia de una nueva fitasa producida por Pichia pastoris a partir de un gen aislado de Serratia odorifera sobre los rendimientos productivos (producción de huevos, consumo de pienso e índice de transformación) y los coeficientes de utilización del fósforo (P) y de otros nutrientes determinando la dosis eficaz mínima de esta nueva enzima a dos edades. La experimentación se realizó con 240 gallinas de la línea Lohmann Brown de 16 semanas de vida. A estas gallinas se asignaron 5 tratamientos experimentales que consistieron en un pienso control y cuatro piensos experimentales que diferían entre sí en los niveles de la nueva enzima (unidades de fitasa (UFT)/kg de pienso). Los tratamientos fueron: C- (control, sin fitasa y con niveles bajos de P), 250 (C- con 250 UFT/kg de pienso), 500 (C- con 500 UFT/kg de pienso), 1.000 (C- con 1.000 UFT/ kg de pienso) y 10.000 (C- con 10.000 UFT/kg de pienso). Durante el experimento se realizó un balance de nutrientes a nivel fecal a las 25 semanas de vida y otro balance de nutrientes fecal e ileal a las 30 semanas de vida. Con ello se calculó el coeficiente de utilización de nutrientes del calcio (Ca) y P, materia seca (MS), materia orgánica (MO), proteína (PB) y energía (EB). Además, se estudió la producción de huevos e índice de Transformación (IT) y el Consumo medio diario (CMD). No se observaron diferencias significativas con la adición de fitasas en los parámetros productivos (peso del animal, CMD, producción de huevos, peso del huevo, masa e IT) respecto al control negativo. En gallinas de 25 semanas, la adición de fitasa mejoró (P <0,05) el coeficiente de utilización de la MS con 1.000 UFT/kg, el coeficiente de utilización de la MO, PB y Ca con 250 UFT/kg y el del P con 500 UFT/kg respecto al pienso sin fitasa. En gallinas de 30 semanas, la adición de fitasa mejoró (P <0,05) el coeficiente de utilización de la MS, MO y el P con 1.000 UFT/kg y el coeficiente de utilización d

[EN] This research aimed to evaluate the effects of inclusion of a new phytase of bacterial origin in the feed of growing pigs, on apparent digestibility coefficient and retention of different nutrients. Five experimental diets differing in the addition of phytase and in phosphorus (P) content were used: positive control (C+) with 7.1g of total / kg P without phytase, negative control (C-) with low P (5.6 g total P/ kg) without phytase and three diets base don C- supplemented with 250, 500 and 1000 phytase units,UFT / Kg of feed. Seventy five male pigs (32.24 ± 2.77 kg live weight on average) were used, in five batches, each batch consisting of 15 pigs. The experimental period lasted 18 days, in each batch (7 days of adaptation to pen and feed, 7 days adaptation to digestibility cage and four days of collection of feces and urine – digestibility trial). In the conditions of this study, the addition of the new phytase in growing pigs at levels of 500 and 1000 UFT / kg produced an increase (p>0.05) in the digestibility of P in 5 to 9 percentage points and an increase in the retention of P in 5.4 and 10 percentage points, respectively compared with diets low in phosphorus and without phytase (C-). Other minerals were not affected by the addition of phytas, [ES] El presente trabajo de investigación tuvo como objetivo evaluar los efectos de incorporación en el pienso de cerdos en crecimiento, una nueva fitasa de origen bacteriano sobre el coeficiente de digestibilidad aparente y retención de los diferentes nutrientes en cerdos en crecimiento. Se utilizaron cinco dietas experimentales que difieren en el nivel de incorporación de la fitasa y en el contenido en fósforo (P): la dieta control positivo (C+) con 7,1 g de P total/Kg sin fitasa, dieta control negativo (C-) con niveles bajos de P (5,6 g P total/Kg) sin fitasa y tres dietas a partir del C- suplementado con 250, 500 y 1000 unidades de fitasa, UFT/Kg de pienso. Se utilizaron 75 cerdos machos (32,24 ± 2,77 Kg peso vivo medio), en 5 tandas, cada tanda conformada por 15 cerdos. El periodo experimental tuvo una duración de 18 días, en cada tanda (7 días de adaptación a corral y pienso, 7 días de adaptación a la jaula de digestibilidad y 4 días de recogida de heces y orina – ensayo digestibilidad). En nuestras condiciones de estudio, la suplementación con fitasa en cerdos en crecimiento, a niveles de 500 y 1000 UFT/kg, produjo un incremento (p>0.05) de la digestibilidad del P en 5 y 9 puntos porcentuales y un aumento en la retención del P en 5,4 y 10 puntos porcentuales, respectivamente, en comparación con dietas bajas en P y sin fitasas (C-). Mientras que otros minerales no se vieron afectados por la dieta suplementada con fitasa.

[EN] Feeding programs promoting daily feed intake (DFI) stability in rabbit males could be useful to ensure successful coverage of their nutritional requirements and for continued production of quality semen. To evaluate two feeding systems designed to reduce DFI variability, 115 rabbit males at age 1.2 years were randomly assigned to three different treatments for 294 days: CS, animals fed ad libitum with a control diet (127-g starch and 281-g total soluble fiber [hemicellulose + soluble fiber] kg(-1) dry matter); SF, males fed ad libitum with diet enriched in soluble fiber (86-g starch and 330-g total soluble fiber kg(-1) dry matter); and R, animals fed with CS diet but daily restricted to maintenance requirements. Feed intake, body weight, body condition, and variability of DFI were controlled every 42 days, and individual semen volume and sperm motility, concentration, acrosome status, and abnormalities every 15 days. In six commercial farms, the number of females inseminated, pregnant and kindling, as well as the number of kits born alive, was registered for 15,893 inseminations with pooled semen from each treatment. DFI was significantly lower for R males than for the other treatments (on average, -12 +/- 4 g/day; P < 0.001). Daily weight gain of R males was close to zero and significantly lower than in the other groups (-1.42 g/day; P < 0.001). Variability of DFI was significantly (P < 0.01) lower for R males (7%) than for males of dietary treatments CS (13%), with SF males showing intermediate values (11%). Semen from R males presented lower sperm abnormalities (-5.9%; P < 0.05) and higher percentages of normal and motile spermatozoa (-3.4% than SF males; P < 0.05). Dietary treatments formulated to reduce DFI variability (SF and R) led to an improvement of kindling to pregnant and kindling to insemination ratio (+0.039 and + 0.060 +/- 0.015, respectively; P < 0.05) compared with CS treatment. In conclusion, a moderate restriction of rabbit males may be usefu

A total of 60 nulliparous crossbred rabbit females were, a posteriori, divided into 2 experimental groups according to their natural “decision” to conceive or not at day 11 post first parturition (L: solely-lactating or LP: lactating-pregnant). This design allowed us to study the evolution of body reserves around first parturition and its influence on the future reproductive success of rabbit females. Primiparous rabbit females that failed to conceive when inseminated at day 11 post-partum (L) seemed to have a higher perirenal fat thickness (PFT) 12 d pre-partum (+0.25 mm; P=0.079) than females that conceived (LP). In the subsequent days, L females showed a significantly higher mobilisation rate than LP females (on av.–0.12 and –0.07 mm of PFT per day, respectively; P=0.007), reaching a lower PFT at partum (5.17 mm vs. 5.62 mm, respectively; P = 0.002). However, due to a greater recovery rate observed in L females (+0.15 vs. +0.08 mm of PFT per day for L and LP females, respectively; P=0.007), PFT at 10 d post-partum was similar (on av. 5.86 mm). These different patterns showed that PFT level at 12 d pre-partum and PFT mobilisation rate onwards seems to drive the start of a new pregnancy. It also seems to modify the energy metabolism of rabbit females, allowing does to recover perirenal fat tissue without compromising the production of milk necessary for the current litter.