Search

[EN] Reducing methane emissions in ruminants with the recycling of agro-industrial by-products is of great importance today. Pruning waste from citrus trees is currently burned or incorporated into soil. Regarding rice straw, this waste is traditionally eliminated through controlled burning, releasing into the atmosphere large amounts of greenhouse gases as well. The aim of this study was to convert this recovered waste into a new animal feed capable of reducing methane emissions in ruminants. The interest in use waste by-products for ruminant nutrition is increasing. Therefore, we replace the beet pulp and cereal straw from dry-non-pregnant goats' diet with orange leaves and rice straw with the objective of studying their effect upon intake, digestibility, energy efficiency, carbon and nitrogen balance, and methane emissions. Considering the huge quantities of crops by-products and pruning waste such as rice straw and citrus leaves produced annually worldwide, and their potential pollution capacity, recycling as feed for livestock is an alternative. The objective was to study these by-products effect on energy balance and methane emissions in 10 Murciano-Granadina goats at maintenance. The control diet (CTR) included barley straw and beet pulp while the experimental diet (ORG) consisted of rice straw and orange leaves. Differences were found for energy intake (248 kJ/kg of BW0.75 greater for CTR than ORG). The intake of metabolizable energy was 199 kJ/kg of BW0.75 lower in ORG than CTR, and the energy efficiency was higher with CTR (0.61) than ORG (0.48). Protein retained in the body was 9 g/goat greater with CTR than ORG, and fat retention in the body was approximately 108 g/goat greater with CTR than ORG. Despite more unfavorable energy balance in response to feeding ORG than CTR, the retention of body energy was always positive. Reductions in CH4 emissions were detected when goats were fed ORG diet (from 22.3 to 20.0 g/d). Overall results suggested that feeding orange leaves and rice straw was effective in reducing CH4 emissions without adversely affecting energy balance., This study was supported by LIFE Project, Spain (ref. LIFE2016/CCM/ES/000088 LOW CARBON FEED).

[EN] The aim of this study was to evaluate the effects of incorporating rice straw and orange leaves into the diets for goats. Ten Murciano-Granadina goats at mid lactation weighing 45 +/- 0.3 kg were used in a crossover design. Two isoproteic and isoenergetic diets (180 g/kg DM and 17 MJ/kg DM, respectively) with alfalfa hay as forage source (33% of DM) were fed. A control diet (CON) incorporated barley as energy source and soy hulls as fiber component. The experimental diet (ORG) replaced barley and soy hulls with orange leaves (19% on DM basis), rice straw (12%, on DM basis) and soya oil (2%). Peas and horsebeans were the protein source in both diets. Each goat received the 2 treatments in 2 periods. Goats were fed the experimental diets and after 14 d on their respective treatments moved to individual metabolism cages for another 7 d. Subsequently, feed intake, total fecal and urine output and milk yield were recorded daily over the first 5 d. During the next 2 d ruminal fluid and blood samples were collected, and then individual gas-exchange measurements were recorded by a mobile open-circuit indirect calorimetry system using a head box. No differences in dry matter intake were detected, and apparent total-tract digestibility was greater in CON than ORG. Efficiency of metabolizable energy intake for milk and maintenance also was lower in response to ORG (0.65 vs. 0.63), with energy balance being negative (-12 kJ/kg of BW0.75) due to mobilization of fat (-16 g/animal vs. 68 g/animal for ORG and CON, respectively). Although actual milk yield was lower in goats fed ORG (2.32 vs. 2.06 kg/d, respectively), energy-corrected milk did not differ (2.81 kg/d on average). In terms of milk quality, milk fat content, and concentrations of monounsaturated (18.54 vs. 11.55 g/100 g milk fat) and polyunsaturated fatty acids (5.75 vs. 3.99 g/100 g milk fat) were greater in goats fed ORG. Based on various indices, the milk produced by ORG would be less atherogenic and thrombogenic than CON milk. Compared with CON, enteric CH4 emission was lower due to feeding ORG (reduction of 38 g CH4/kg milk fat). Data suggest that greater fat mobilization in goats fed ORG might have been due to the apparent lack of synchrony between degradable protein and carbohydrate and the lipogenic nutrients associated with the lower cereal content of the ORG diet. Thus, goats fed ORG seemed to rely more on fat depots to help meet energy requirements and reach optimal performance. As such, the lower content of glucogenic nutrients in ORG did not favor body fat deposition and partitioning of ME into body tissue. Overall, responses in terms of CH4 emissions and milk quality suggest that inclusion of rice straw and orange leaves in diets for small ruminants could be a valuable alternative to reuse, recycle and revalue agricultural by-products., This study was supported by LIFE Project, Spain (ref. LIFE2016/CCM/ES/000088 LOW CARBON FEED), funded by the EU Commission (Brussels, Belgium). The authors have not stated any conflicts of interest.

[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 lower CTTAD of OM (-0.055 +/- 0.004, P < 0.001) and GE ( - 0.034 +/- 0.005, P < 0.001) without affecting DE and DP contents. This dietary variation increased DM content of caecal digesta ( +21 +/- 3 g/kg, P < 0.001), but did not affect the other caecal digesta traits. Feed intake was higher ( + 4.9 %, P < 0.001), although differences were dependent on the growth phase and the SF level (maximum difference at 35-49 days with low SF diets, + 11.0 %, P < 0.001; minimum difference at 49-63 days with high SF diets, + 1.0 %, P = 0.689), but did not affect LW gain and consequently impaired the feed to gain ratio ( + 5.1 %, P < 0.001). No effect was observed on dressing out, but the dissectible fat proportion increased ( + 6.7 +/- 1.1 g/kg reference carcass weight, P < 0.001)., Financial support was provided by the Spanish Ministry of Education and Science (Project AGL2006-07596).

[EN] The aim of this study was to assess the effect of substitution of dietary corn grain by dry citrus pulp or soybean hulls on energy and nitrogen partitioning, substrate oxidation, methane emission, and milk performance in dairy goats during midlactation. Twelve multiparous Murciano-Granadina goats of similar body weight (41.7 +/- 2.8 kg) were split in 3 groups in an incomplete crossover design. One group of 4 goats was fed a mixed ration with 605 g/kg of dry matter of corn grain (CRG), another group replaced corn grain with dry citrus pulp (CTP), and the last with soybean hulls (SYH). The goats were allocated to individual metabolism cages. After 14 d of adaptation, feed intake, total fecal and urine output, and milk yield were recorded daily over a 5-d period. Then, gas exchange measurements were recorded by a mobile open-circuit indirect calorimetry system using a head box. Dry matter intake was similar for all 3 groups (1.53 kg/d, on average). Total replacement of the concentrate with fibrous by-products increased fiber apparent digestibility. The metabolizable energy intake was significantly greater for diet CRG than SYH (1,193 vs. 1,079 kJ/kg of BW0.75, respectively), CTP showed an intermediate value. The heat production was higher for the fiber diet than starchy diet (908 vs. 843 kJ/kg of BW0.75 for SYH and CRG, respectively). The efficiency of use of metabolizable energy for milk production obtained by regression was 0.59. Goats fed CTP and SYH diets produced similar CH4 emissions (34.8 g/d, on average), significantly higher compared with goats fed the CRG diet (24.7 g/d). Goats of the 3 treatments were in negative energy balance, so the oxidation of fat was greater than for carbohydrates. No significant differences were observed for milk production (1.72 kg/d), and milk fat was significantly greater for a more fibrous diet compared with a starchy diet (6.57 vs. 4.95% in SYH and CRG, respectively), This study was supported by the Instituto INIA Project (Madrid, Spain; ref. RTA2011-00107-C02-02).

BACKGROUND Microbial corrected in situ estimates of the ruminal undegraded fraction (RU) and intestinal effective digestibility (IED) of amino acids (AA), except tryptophan, of rye, wheat and corn grains, wheat bran, wheat and barley distilled dried grains and corn gluten feed were measured on three rumen- and duodenum-cannulated wethers using 15N-labelling techniques and considering ruminal rates of particle comminution and outflow. RESULTS The lack of microbial correction led to overestimations of the intestinal digested fraction that rose with the increase in ruminal degradability. Thus these overestimations varied widely among feeds (from 4.3 to 32.1% for total analysed AA) and among AA. Digestion led to large changes in the AA supply that were greater in the rumen than in the intestine. The impact of these changes on the protein value is conditioned by the magnitude of the undegraded protein fraction. CONCLUSION Microbial contamination taking place in the rumen and changes in the AA supply with digestion should be considered to attain accurate estimates of AA digestion. Globally, digestion improved the AA supply in rye, wheat and wheat distilled dried grain and decreased it in corn and corn gluten feed by reducing the supply of valine and basic AA, especially lysine. © 2014 Society of Chemical Industry

BACKGROUND Microbial corrected effective in situ estimates of ruminal undegraded fraction (RU) and intestinal effective digestibility (IED) of dry matter (DM), crude protein (CP) and amino acids (AA) of expeller palm kernel (EPK) and rapeseed meal (RSM) were measured on three rumen- and duodenum-cannulated wethers using 15N labelling techniques and considering ruminal rates of comminution (kc) and outflow (kp) of particles. RESULTS The lack of kc and microbial correction overestimated the RU of DM by 4.91% (EPK) and 9.88% (RSM). The lack of this correction also overestimated in both feeds the RU of CP, individual and total (TAA) AA as well as the IED of DM, CP, TAA and most AA. RU estimates were higher for CP than for TAA, but the opposite was observed for IED. The intestinal digested fraction was higher for CP than for TAA: 17.4% (EPK) and 13.8% (RSM). Digestion led to large changes in the essential AA profile in both feeds. CONCLUSION The lack of kc and microbial correction as well as CP-based results leads to considerable overestimations in the protein use of both feeds. Digestion aggravates the lysine deficiency of EPK but has global positive effects in the absorbed profile of RSM. © 2013 Society of Chemical Industry

[EN] The effects of the composition of pen-weaning diets on apparent ileal digestibility of nutrients and caecal environment were studied in growing rabbits. Eight diets were formulated according to a 2 x 2 x 2 factorial design to increase acid detergent fibre (ADF) from 230 to 290 g kg(-1) dry matter (DM) at the expense of mainly starch, to increase neutral detergent soluble fibre (NDSF) from 145 to 185 g kg(-1) DM at the expense of mainly starch, and to reduce crude protein (CP) content from 175 to 145 g kg(-1) DM. A total of 32 litters of eight kits were randomly assigned to the diets at 17 days of age, weaned at 28 days of age and slaughtered at 35 days of age to collect samples of ileal and caecal contents. The substitution of ADF for starch reduced the coefficient of apparent ileal digestibility (CAID) of DM (0.292 vs. 0.229; P, Financial support was provided by the Ministerio de Educacion y Ciencia of Spain (Proyecto AGL2006-07596). Authors thank J. Garcia from the Universidad Politecnica de Madrid (Spain) for the analyses of ytterbium.

[EN] Effects of the correction of microbial contamination (using N-15 techniques) and of considering the comminution rate (k (c)) of particles in the rumen on effective estimates of the ruminally undegraded (RU) fraction and its intestinal effective digestibility (IED) were examined in a sample of dehydrated sugar beet pulp (DBP) generating composite samples (from rumen-incubated residues) representative of the chemical composition of RU. Tested fractions were dry matter (DM), organic matter (OM, tested only for RU), crude protein (CP) and amino acids (AA). The study was performed on three rumen and duodenum cannulated wethers fed with a 2:1 (fresh weight basis) chopped oat hay-to-concentrate diet supplied at 40g DM/kg BW0 center dot 75 in six equal meals per day. The DBP showed sigmoid degradation kinetics: the fractional degradation rate increased by 5 center dot 8 times as time (h) increased from 0 to infinity. The k (c) rate (measured in the diet concentrate) represented 5 center dot 74% of the total rumen retention time of particles. As a result, the RU of DM was over-evaluated by 6 center dot 53% when k (c) was not considered. Microbial contamination of RU was high as in DM as in CP. Therefore, the overestimation of RU of DM was increased to 12 center dot 2% when this contamination was not corrected. The lack of this correction also led to large over-evaluations of RU and IED of CP and AA. As a result, the overestimation of the intestinal digested fraction was 40 center dot 9% for CP and 45 center dot 0% for total analysed AA. This overestimation varied largely among AA (from 18 center dot 9 to 88 center dot 7%). Corrected proportions of RU and IED were also variable among AA. Hypotheses on the causes of this variability are given. Resultant changes in the AA profile of the intestinal digested protein had some negative impact on the supply of essential AA and cysteine without affecting lysine. This problem is limited because the microbial protein synthesized from DBP fermentation in the rumen is largely predominant in the AA supply to the host., This work was supported by the CICYT-funded Project AGL 2006-08300. Analyses of 15N isotope ratios were performed at the Servicio Interdepartamental de Investigacion, Universidad Autonoma de Madrid. Spain.

[EN] Albendazole (ABZ) residues in goat's milk and their effect on the response of microbial inhibitor tests used for screening antibiotics were evaluated. A total of 18 Murciano-Granadina goats were treated with ABZ and individually milked once a day over a 7-day period. ABZ quantification was performed by high performance liquid chromatography. The ABZ parent drug was not detected. The maximum concentration of its metabolites (ABZ sulfoxide, ABZ sulfone, and ABZ 2-aminosulfone) was reached on the 1st day posttreatment (260.0 ± 70.1 mg/kg, 112.8 ± 28.7 mg/kg, 152.0 ± 23.6 mg/kg, respectively), decreasing to lower than the maximum residue limit (MRL, 100 mg/kg) on the 3rd day post treatment. Milk samples were also analyzed by microbial tests [Brilliant Black Reduction Test (BRT) MRL, Delvotest SP-NT MCS and Eclipse 100], and only one positive result was found for Delvotest SP-NT MCS and Eclipse 100. However, a high occurrence of positive outcomes was obtained for BRT MRL during 6 days post treatment, whereas ABZ residues were not detected from the 4th day post administration, suggesting that factors other than the antiparasitic agent might affect the microbial test response., This work is part of the AGL-2009-11524 funded by the Ministry of Science and Innovation (Madrid, Spain) and the Generalitat Valenciana (ACOMOP/2012/164, Valencia, Spain).

[EN] This Research Communication reports interferences related to the administration of ivermectin in lactating dairy goats on the response of microbial tests for screening antibiotics in milk. Twenty-eight Murciano-Granadina goats, naturally infested with Sarcoptes scabiei var. caprae, were treated with a subcutaneous injection of ivermectin (200 mu g/kg b.w.). To prevent re-infestation, a second dose was applied 7 d later. Individual milk samples were collected, daily, up to 15 d post-treatment. Milk samples were analysed by microbial inhibitor tests (BRT MRL, Delvotest SP-NT MCS and Eclipse 100) and ivermectin residues were quantified by HPLC. A large number of positive results were obtained for all microbial tests, especially on the first day after treatment (BRT MRL = 464%; Delvotest SP-NT MCS = 143%; and Eclipse 100 = 178%). However, the highest concentration of drug residues in milk (243 ng/ml) was detected on the tenth day after treatment, when positive outcomes were relatively lower (BRT MRL = 178%; Delvotest SP-NT MCS = 107%; and Eclipse 100 = 74%). Results herein suggest that factors related to the ivermectin treatment other than drug residues in milk, or alterations produced by the parasitic disease itself affecting the immune response of animals, could be the cause of false-positive results in microbial tests. It can be concluded that the application of ivermectin in dairy goats infested with sarcoptes mange during lactation produces persistent drug residues in milk, and could also cause false-positive results in microbial inhibitor tests for screening antibiotics., This work is part of the AGL-2009-11524 funded by the Ministry of Science and Innovation (Madrid, Spain) and the Generalitat Valenciana (ACOMOP/2012/164, Valencia, Spain).

Due to their fibrous nature, distillers dried grains with solubles (DDGS) from the bioethanol industry could be considered an interesting feedstuff for rabbit nutrition. To characterize the DDGS available in the Iberian Peninsula the chemical, amino acid and fatty acid composition of eight DDGS batches (2, 2 and 4 from barley, corn and wheat grains, respectively) was performed. Five diets were formulated to determine the nutritive value of DDGS in growing rabbits by the substitution method: a control diet and four experimental diets containing 200 g of the DDGS being evaluated kg−1 dry mater (DM) [DDGS from national barley, national corn, Brazilian corn and national wheat grains]. The digestibility trial was performed using 60 three-way crossbred fattening rabbits (12 per diet), aged 42 days with average live weight of 1.49 kg (S.E.: 0.033 kg). DDGS can be characterized as a raw material really rich in fibre (neutral detergent fibre and neutral detergent soluble fibre) and crude protein (CP, on av. 352, 208 and 318 g kg−1 DM, respectively). Barley DDGS had higher fibre and lower protein contents than wheat DDGS (+25 g of acid detergent fibre and −91 g of CP kg−1 DM, respectively; P

[EN] Feeding systems for dairy ruminants need to ensure high intake of energy to achieve maximum milk production potential. This might be accomplished by raising the dietary concentration of cereal grain. Increasing the concentration of starch in diets can lead to undesirable ruminal fermentation, and to prevent it, the partial replacement of cereal grain with low starch by-product feeds is recommended. The purpose of the present study was to compare the effect of fed two mixed diets to dairy goats differing in the type of carbohydrate (starch vs. easily degradable fiber). Energy and nitrogen balance, short chain fatty acids in rumen liquor and milk performance in dairy goats during mid lactation were determined. Enteric methane (CH4) emissions and CH4 production from manure were determined as well. Ten multiparous Muciano-Granadina goats were assigned to two isoenergetic and isoproteic diets (19.1 MJ/kg dry matter (DM) and 18.1% of CP, DM basis) in a crossover design. One group was fed a mixed ration with 21.9% of starch (HS diet) and the other (LS diet) with 7.0% of starch. HS diet had 36% of barley (as source of starch) and it was replaced with soy hulls and corn gluten feed in LS diet (as potentially digestible fiber). No differences were observed for dry matter intake in both diets (2.05 kg/d, on average). A significant increase of ruminal acetic acid was found for low starch diet (66.4 and 56.6 mol/100 mol for LS and HS diet, respectively). No significant effect was found among diets for enteric CH4 emissions (28.5 g/d, on average). Manure derived maximum potential yield was (Bo) higher in HS diet, with 5.9 L CH4/kg OM vs. 0.28 L CH4/kg OM for LS diet, probably associated with the low ADF digestibility. Differences among diets were found for milk production (2.4 vs. 2.2 kg/d for HS and LS, respectively), and greater milk fat was observed with LS diet compared with HS (6.4% vs. 5.5%, respectively)., This study was supported by INIA Project, Spain (ref. RTA2011-00107-C02).

[EN] Twelve diets were formulated using the same raw materials and including 3% of sunflower oil at 3 different oxidation levels [fresh (F), peroxidised (P; 55ºC for 11 d; 83 meq O2/kg oil) and highly-oxidised (O; 140ºC for 31 h; [Ro]-anisidine value of 125)], with 2 levels of [ALFA]-tocopherol supplementation (0 and 100 ppm), and 2 levels of Zn supplementation (0 and 200 ppm). A growing trial with 900 twenty eight d old rabbits was carried out in order to study the effect of the oxidation and protection level of supplemented oil on the performance of animals from weaning (28d) to 63 d of age. Another coetaneous trial was performed to study the effect of the oxidation level of sunflower oil (F, P and O) on caecal activity around weaning, using 120 suckling rabbits randomly re-allocated into 12 litters of 10 kits (4 litters per diet) from 17 to 44 d of age. Four rabbits per litter were slaughtered at 30 and 44 d (16 rabbits/treatment and age). Full gastro-intestinal tract and caecum were weighed and pH, dry matter (DM), ammonia nitrogen (NH3) and volatile fatty acids concentration (VFA) values in caecal content were measured. No effect was observed either in the mortality rate, body weight gain, feed intake or conversion rate throughout the growing period when peroxidised or oxidised oils were included in the diet, being on average 32%, 45.1 g/d, 107.6 g DM/d and 2.44, respectively. Dietary supplementation with [alfa]-tocopherol and/or Zn had no effect on the mortality rate, feed intake and performance of rabbits during the fattening period. Daily weight gain just after weaning (28 to 30 d of age) was higher for kits receiving the diet supplemented with F and O diets than those with the P diet (55, 50 and 35 g/d, respectively; P, This work was supported by a grant from the Ministry of Science and Technology (AGL2003-06559-C02-02).

Aflatoxin M1 (AFM1) distribution in curd, whey, Manchego cheese, the traditional Spanish whey cheese Requesón and Requesón whey, and its stability during two different cold treatments, have been studied. Raw ewe’s milk was artificially contaminated with AFM1 in a final concentration of 50 and 100 ng kg-1, and was used to produce Manchego cheese. AFM1 determinations were carried out by HPLC with fluorimetric detection after immunoaffinity clean-up. The mean AFM1 concentrations in the produced curd and Manchego cheese were approximately 2- and 3-fold higher than the initial milk they were made from, and the levels of this toxin remaining in whey were 42.3 % and 51.3 % of the initial concentrations. In the Requesón samples, the mean AFM1 values were 1.7 times higher than those in the corresponding whey, while 33.7 % and 44.4 % of the AFM1 concentration detected in milk also appeared in the Requesón whey. Short refrigeration and freezing periods did not affect the toxin levels in either curd or Requesón samples. When ewe’s milk destined for Manchego cheese-making is AFM1-contaminated at the EU limit level (50 ng kg-1) or double, a concentration of this toxin will appear in the manufactured products, but values will be considerably below the toxic doses (Tolerable Daily Intake = 2 ng kg-1 body weight per day), which poses a human health problem., U istraživanju je utvrđivana razdioba aflatoksina M1 (AFM1) u grušu, sirutki, Manchego siru, tradicionalnom španjolskom Requesón siru načinjenom od sirutke i Requesón sirutki te njegova stabilnost tijekom dva različita tretmana hlađenja. Svježe ovčje mlijeko je “umjetno” kontaminirano s AFM1 u završnoj koncentraciji od 50 i 100 ng kg-1 i korišteno je u proizvodnji Manchego sira. Koncentracije AFM1 mjerene su HPLC fluorometrijskom detekcijom nakon potpunog pročišćavanja imunoafinitetnim postupkom. Srednje vrijednosti koncentracija AFM1 u proizvedenom grušu i Manchego siru bile su oko 2 do 3 puta veće od prvotnog mlijeka od kojeg su načinjeni, a razine toksina zaostale u sirutki bile su 42,3 % i 51,3 % od početne koncentracije. U Requesón uzorcima srednje AFM1 vrijednosti bile su 1,7 puta veće od onih u uzorcima sirutke, dok su AFM1 koncentracije 33,7 % i 44,4 % utvrđene u mlijeku, također utvrđene i u odgovarajućim uzorcima Requesón sirutke. Kratka razdoblja hlađenja i zamrzavanja nisu utjecala na razinu toksina u grušu i Requesón uzorcima. U slučaju kada je ovčje mlijeko namijenjeno za proizvodnju Manchego sira kontaminirano s AFM1 na razini EU-propisa (50 ng kg-1), ili dvostruko većom od te granice, određena koncentracija tog toksina pojavit će se u prerađevinama, ali će vrijednosti biti znatno niže od toksičnih doza (podnošljive dnevne doze = 2 ng kg-1 tjelesne mase dnevno), što predstavlja određeni problem za ljudsko zdravlje.

[EN] The effects of the dietary inclusion of fats with different origin (lard or vegetal oil), fatty acid profile (linseed or sunflower), oxidation level (fresh, peroxidised: 11 d at 55ºC or oxidised: 31 h at 140ºC) and vitamin E supplementation (0 or 100 ppm) on the rabbit diet apparent digestibility were studied. Digestibility coefficients of dry matter, organic matter, crude protein, ether extract and gross energy were determined in eight diets using 58 rabbits aged 49 d. Contrast analysis between groups of diets showed that lard, characterised by a greater saturated fatty acid content, compared with vegetal oils, rich in unsaturated fatty acid, reduced the apparent digestibility of ether extract (62.3 vs. 68.4%; P=0.0329). However, there were no significant differences in the nutrient digestibility when linseed or sunflower oils (rich in [omega]-3 or in [omega]-6 polyunsaturated fatty acids, respectively) were compared. The oxidation degree of the sunflower oil and the supplementation with 100 ppm of vitamin E to the diets did not modify the apparent digestibility values of any dietary fraction., This work was financed by the Ministry of Science and Technology (AGL2003-06559-C02-02)

Effects of considering the particle comminution rate (k(c)) in addition to particle rumen outflow (k(p)) and the ruminal microbial contamination on estimates of by-pass and intestinal digestibility of DM, organic matter and crude protein were examined in perennial ryegrass and oat hays. By-pass k(c)-k(p)-based values of amino acids were also determined. This study was performed using particle transit, in situ and N-15 techniques on three rumen and duodenum-cannulated wethers. The above estimates were determined using composite samples from rumen-incubated residues representative of feed by-pass. Considering the comminution rate, k(c), modified the contribution of the incubated residues to these samples in both hays and revealed a higher microbial contamination, consistently in oat hay and only as a tendency for crude protein in ryegrass hay. Not considering k(c) or rumen microbial contamination overvalued by-pass and intestinal digestibility in both hays. Therefore, non-microbial-corrected k(p)-based values of intestinal digested crude protein were overestimated as compared with corrected and k(c)-k(p)-based values in ryegrass hay (17.4 vs 4.40%) and in oat hay (5.73 vs 0.19%). Both factors should be considered to obtain accurate in situ estimates in grasses, as the protein value of grasses is very conditioned by the microbial synthesis derived from their ruminal fermentation. Consistent overvaluations of amino acid by-pass due to not correcting microbial contamination were detected in both hays, with large variable errors among amino acids. A similar degradation pattern of amino acids was recorded in both hays. Cysteine, methionine, leucine and valine were the most degradation-resistant amino acids., This work has been supported by the CICYT-funded Project AGL 2006-08300. Analyses of 15N isotope ratios were performed at the Servicio Interdepartamental de Investigacion, Universidad Autonoma de Madrid, Spain.

The methane (CH4) production was determined by indirect calorimetry. Twelve Murciano-Granadina goats at late lactation were fed with two isoenergetic diets (17.46 MJ/kg DM) with two different quantities of starch (29.03% vs. 14.44%) in a cross over design. Alfalfa hay and barley straw were the source of forage and mixes of concentrate (65%) were used to achieve the requirements during lactation. The goats were allocated to individual metabolism cages. After 8 d of adaptation, feed intake, total fecal and urine output, and milk yield were recorded daily during a 5 d period. Then, gas exchange measurements were recorded by a mobile open-circuit respirometry system using a face mask. Methane production was 60.60 and 100.37 kJ/kg BW0.75/d for the diet high and low in starch, respectively. Not significant differences were observed for milk production and composition between diets.The methane conversion factor was higher for diet lowest in starch (6.70% vs. 3.26%).

[EN] An in vivo digestibility trial and a fattening trial were carried out to evaluate the potential dietary use of a dehydrated Ceratitis capitata exhausted diet (CED) on growing rabbits. For the digestibility trial, 2 pelleted diets were manufactured including 0 and 50% of dry matter (DM), excluding the premix, from CED (CED0 and CED50 diets, respectively), using 10 three-way crossbred rabbits of 42 days of age per diet. For the fattening trial, 3 almost iso-energetic, iso-protein and iso-fibrous pelleted diets were manufactured including 0, 15 and 30% of DM from CED (CED0, CED15 and CED30 diets, respectively), and offered to 180 weaned rabbits (60 per experimental diet) randomly housed in collective cages (5 animals per cage). Health status and performance traits were monitored from 28 to 58 days of age. CED was characterised by high water content (51%), but its DM was rich in fibre (15% ADF), high-digestible carbohydrates (27% of soluble sugars) and protein (17% of CP). The lysine (0.94% DM) and methionine (0.93% DM) contents of CED were similar to those observed for some common vegetal protein concentrates, but cysteine content was low (0.26% DM). The dietary inclusion of CED at 50% increased DM, organic matter and gross energy apparent digestibility coefficients (approx. +8%; P, This research was financed by the company Tragsa S.A. We wish to express our gratitude to Mr. Jaime García de Oteyza and Mr. Rafael Argilés for their valuable collaboration throughout the experiment. English text version revised by Neil Macowan.

[EN] Seven diets were formulated in order to determine the nutritive value of whole maize plant at three stages of maturity by substitution of a control diet (C) with 20% and 40% whole maize plant at early dough, mid-dent and mature stages of grain. A digestibility trial was performed with 74 rabbits. Digestible protein and energy values of whole maize plant at different maturity stages were calculated by substitution and regression procedures. A fattening experiment was carried out with 200 rabbits from weaning (28 days of age) giving ad libitum either diet C or 20% mature whole maize plant. One hundred and forty-three rabbits were slaughtered at 63 days of age and some carcass traits were measured.The crude protein and fibre content of whole maize plant decreases as the kernel matures (CP: 8.3, 8.1 and 7.6% DM; CF: 15.8, 12.6 and 13.4% DM; NDF: 45.3, 38.0 and 38.0% DM; ADF: 19.1, 15.0 and 16.1% DM for early dough, mid-dent and mature stages, respectively). The digestible energy concentration, calculated by regression, of whole maize plant increased (P