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Introducción. Brycon moorei (Dorada) es una especie endémica de la cuenca del río Magdalena con una fuerte presión pesquera comercial, deportiva y de consumo. Sin embargo, es considerada altamente vulnerable por la pérdida de sus hábitats. Objetivo. Observar y determinar algunas estructuras del estado larval usando Microscopía Electrónica de Barrido (MEB). Materiales y métodos. En un sistema de recirculación de agua se obtuvieron larvas por reproducción seminatural usando extracto de hipófisis de carpa (EHC). Para la visualización en MEB, 10 larvas a diferentes tiempos de desarrollo fueron fijadas en solución de Karnovsky, siguiendo los protocolos internos del Centro de Microscopía Avanzada (CAM) de la Universidad de Antioquia. Resultados. De la inducción hormonal se obtuvieron ovocitos de 1110.7±97.3 μm de diámetro; el tiempo de latencia fue de 6 horas a una temperatura de 26°C; la longitud total y el peso de la larva recién eclosionada fue de 3,05±0,05 mm y 1,8±0,2 mg respectivamente. Las observaciones en MEB muestran células del pavimento que tapizan el cuerpo en la eclosión; neuromastos, el primordio del sistema branquial, células olfativas ciliadas y la glándula de cemento. El sistema de recirculación permitió mantener las condiciones de calidad de agua dentro del confort de la especie, asegurando sobrevivencias larvales del 95 %. Conclusiones. Las microfotografías de MEB permitieron determinar estructuras como células especializadas asociadas a su comportamiento caníbal (olfato, detección de ondas) y otras relacionadas con su hábitat (glándula de cemento). A su vez el sistema de recirculación permite un adecuado manejo ambiental de las larvas.

We investigated whether dietary supplementation with Aurantiochytrium sp. meal, a DHA-rich source (docosahexaenoic acid, 22: 6 n-3), fed during long-term exposure to cold-suboptimal temperature (22 °C, P1), followed by short-term exposure to higher temperatures (28 °C, P2, and 33 °C, P3), would promote oxidative damage in Nile tilapia (Oreochromis niloticus). Two supplementation levels were tested: 1.0 g 100 g

This study evaluated the protein requirement of Litopenaeus vannamei post-larvae during the initial rearing phase in a biofloc system. Five different diets were evaluated with increasing concentrations of crude protein: 31.28, 36.29, 41.57, 46.34, and 51.74 g 100 g-1 CP. Post-larvae (0.16 ± 0.01 g) were stocked at a density of 450 PL m-3 in 400 L tanks. Water quality parameters were maintained within the limits recommended for shrimp farming. After 38 days, a regression analysis revealed that levels of CP content (65.29 í 72.83%), EE (10.45 í 11.65%) and body N (10.45 í 11.64%) increased with increasing protein levels in the diet. A similar trend was observed in the biofloc sludge with respect to CP and N. Survival exceeded 80%, and the shrimp with diets containing 31.28 to 46.34g 100 g-1 CP presented an increase in final weight (1.52 í 2.61 g), productivity (0.69 í 1.10 Kg m-3), weight gain (1.38 í 2.44 g), and feeding efficiency (77.28 í 101.68%), whereas these indices decreased to51.74 g 100 g-1 CP. Crude protein content from 44.26 to 47.12 g 100 g-1 provided the best growth performance during the initial rearing phase of Pacific white shrimp in a biofloc system.

Shrimp farming is one profitable sector of aquaculture and the Pacific white shrimp (Litopenaeus vannamei) is the most cultivated species worldwide. Nutrition is considered as one of the greatest challenges in shrimp farming due to its dependence on fishmeal (FM) as an ingredient in the feed. The main goal of the present work was to analyse if the substitution of FM by yellow mealworm (Tenebrio molitor) meal (TM) influences digestive enzyme expression, haemolymph parameters or the intestinal microbiota of shrimp juveniles. Shrimps (average initial weight 4.42±0.02 g) were fed five experimental diets where FM protein was gradually substituted by TM protein (0, 25, 50, 75, and 100%). The shrimps were fed four times per day with an amount equivalent to approximately 6% of their biomass for 42 days. The total haemocyte count, protein concentration and prophenoloxidase activity in the haemolymph were not significantly altered (P>0.05) when FM was substituted by TM. However, the agglutinating activity of shrimp serum determined against dog erythrocytes was higher in the shrimp group fed 25% TM. The absolute and specific activities of trypsin, chymotrypsin, lipase, α-amylase and the patterns of proteolytic activities were not affected by the dietary treatments. The shrimp gut bacterial microbiota profile was similar with the genera Pseudoalteromonas, Rubritalea, Ruegeria, Tenacibaculum, and Vibrio detected. These results show that TM is viable alternative for the replacement of FM, without any deleterious effects on expression of key digestive enzymes, gut microbiota or the immune system of the Pacific white shrimp.

This study designed a promising integrated model for production of fatty acids and aquaculture inputs using the microalgal biomass of Choricystis minor var. minor. Cultures under photoautotrophic, heterotrophic, and mixotrophic nutritional modes were conducted in fed-batch and the lipids from the different biomasses were extracted and quantified. Then, the biomasses without lipids were used to feed the microcrustacean Daphnia similis. The results indicated the mixotrophic nutritional mode as the most suitable for the production of biomass (8.27 ± 0.70 g L−1) and lipids (32.02 ± 0.11%). In contrast, biomass from the heterotrophic nutritional mode was the most promising for feeding D. similis after lipid extraction (2370 ± 372 Daphnia L−1). The integrated chain developed for biodiesel and aquatic feed is a promising alternative to produce energy with ultra-low environmental impact.

Microalgae biomass is considered one of the most promising raw materials for the development of high commercial value products, mainly because they are potential sources of proteins, lipids, carbohydrates, and vitamins. In this way, the optimization of culture medium of these microorganisms can help to reduce production costs, making final products more accessible. In this sense, the present study aimed to investigate the effect of different trace metal concentrations on growth and biochemical composition of Scenedesmus obliquus. Cultures of S. obliquus were performed using the LCA-AD medium (pH 7.6), in 2-L cylindrical borosilicate glass flasks that were constantly stirred by bubbling 0.7% CO2 enriched air (v/v), irradiance ranging from 520 to 1200 μmols m−2 s−1, and temperature at 22 ± 1 °C. Four trace metal concentrations were tested: control (standard concentration used on Bold’s Basal Medium), ten (10−1), hundred (10−2), and thousand (10−3) times less than control. The trace metal concentration did not significantly affect the growth of S. obliquus – all treatments have reached about 4.2 g L−1 on the tenth day of cultivation. As well for growth performance, no significant differences were observed among the treatments for biomass composition percentages. The dry S. obliquus biomass was mainly composed of carbohydrates (about 65%), crude protein (about 20%), and finally lipids (about 12%). These findings suggest that up to 1000-fold reduction in trace metal concentration does not affect the growth and biochemical composition of the green microalga S. obliquus.

Apparent digestibility coefficients (ADCs) of nine protein ingredients were determined for pirarucu Arapaima gigas, a Neotropical fish species with great aquaculture potential in the Amazon. ADCs of crude protein, energy and dry matter were determined by feces sedimentation in cylindrical-conical tanks. Experimental diets were composed of 795 g kg-1 of the reference diet, 5 g kg-1 of chromic oxide and 200 g kg-1 of the following test ingredients: fish by-product meal, salmon by-product meal, poultry by-product meal, hydrolyzed feather meal, meat and bone meal, blood meal, soybean meal, corn gluten meal and corn gluten feed. Blood meal, meat and bone meal and corn gluten feed resulted in low ADCs for pirarucu, whereas corn gluten meal, poultry by-product meal and soybean meal were better digested, indicating that these ingredients may be potential protein sources in feed formulations for pirarucu. The other animal protein ingredients presented intermediate ADCs values and, together with blood meal and meat and bone meal, they demonstrate that the nutritional quality of the animal by-products tested could be improved, especially by enhancing the processing methods of this group of ingredients. Made available in DSpace on 2019-09-19T00:36:36Z (GMT). No. of bitstreams: 1 CNPASA2019lajar.pdf: 389984 bytes, checksum: f0b92695cb0bdfd4cedfc0fae19dd07a (MD5) Previous issue date: 2019

This study evaluated the use of microalgae (Aurantiochytrium sp.) meal as a substitute for fish oil in the diet of juvenile Pacific white shrimp (Litopenaeus vannamei) reared in a clear‐water system. Dietary treatments at five replacement levels (0%, 25%, 50%, 75%, 100%) were performed in triplicate. After 46 days, only a slight difference in shrimp final weight was observed among treatments (0.61 g). An increase in final weight was observed with replacement of up to 50% fish oil for microalgae meal, while the optimal percentage of replacement estimated was 44.7%. Feed conversion rate (FCR) of animals fed a diet of Aurantiochytrium sp.meal to replace up to 50% fish oil decreased, and the optimal percentage of replacement estimated was 49.3%. The fatty acids profile in shrimp muscle tissue demonstrated an increase in docosahexaenoic acid (DHA) from 10.03% to 14.28% with increased replacement of fish oil by microalgae meal in the diet. Therefore, the partial replacement of fish oil by microalgae meal resulted in improved shrimp growth and FCR, and total replacement of dietary fish oil had no negative effects on these parameters. In addition, inclusion of microalgae meal raises the level of DHA in shrimp muscle.

Resumen Para Brycon moorei, los datos sobre morfometría, en estados iniciales del desarrollo, son inexistentes. El objetivo de este estudio fue establecer las principales relaciones alométricas en los estadios tempranos de B. moorei. Se analizaron 12 variables merísticas en un tiempo experimental que transcurrió desde la eclosión hasta los 15 días post-eclosión. En el estadio larval vitelino (LV) se registró, en promedio: longitud total (LT) de 4,74 ± 0,05 mm; longitud estándar (LE) de 4,21 ± 0,07 mm; longitud del hocico (SnL) 0,3 ± 0,01; diámetro del ojo (ED) 0,37 ± 0,007 mm; longitud de la cabeza (HL) 1,02 ± 0,04 mm; altura de la cabeza (HH) 0,88 ± 0,069 mm; altura del cuerpo (-BH) 1,26 ± 0,01 mm; longitud hocico-aleta pectoral (SnPF) 1,35 ± 0,034; ausencia de aletas pélvicas, anales y dorsal y el peso fue de 1,8 ± 0,2 mg. En la etapa juvenil (J), las medidas fueron: LT de 25,66 ± 0,64 mm; LE de 21,49 ± 0,63 mm; SnL de 1,69 ± 0,059 mm; ED de 1,71 ± 0,048 mm; HL de 6,33 ± 0,21 mm; HH de 4,89 ± 0,47 mm; BH de 6,13 ± 0,17 mm; SnPF de 6,48 ± 0,19 mm; SnPeF de 10,83 ± 0,28 mm; SnDF de 11,16 ± 0,33 mm; Sn-AF de 3,68 ± 0,34 mm; el peso fue de 221,6 ± 15,84 mg. Para LV, el número de miómeros pre-anales fue 28,65 ± 4,7; los post-anales fueron 23,85 ± 4,27, con un total de 52,47 ± 8,34; para J los miómeros no fueron visibles. Esta información es fundamental para fines ecológicos y productivos en B. moorei. Abstract For Brycon Moorei, morphometry data in early stages of development is non-existent. The objective was to establish the main allometric relationships in the early stages of B. moorei. 12 meristic variables were analyzed in an experimental time ranging from hatching to 15 days post-hatching. In the larval vitelline stage (LV), it was recorded on average: total length (TL) of 4.74 ± 0.05 mm; standard length (EL) of 4.21 ± 0.07 mm; snout length (SnL) 0.3 ± 0.01; eye diameter (ED) 0.37 ± 0.007 mm; head length (HL) 1.02 ± 0.04 mm; head height (HH) 0.88 ± 0.069 mm; body height (BH) 1.26 ± 0.01 mm; snout-pectoral fin length (SnPF) 1.35 ± 0.034; absence of pelvic, anal and dorsal fins and the weight was 1.8 ± 0.2 mg. In juvenile stage (J), the measures were: LT of 25.66 ± 0.64 mm; LE of 21.49 ± 0.63 mm; SnL of 1.69 ± 0.059 mm; 1.71 ± 0.048 mm ED; HL 6.33 ± 0.21 mm; HH of 4.89 ± 0.47 mm; BH of 6.13 ± 0.17 mm; SnPF of 6.48 ± 0.19 mm; SnPeF of 10.83 ± 0.28 mm; SnDF of 11.16 ± 0.33 mm; Sn-AF of 3.68 ± 0.34 mm; the weight was 221.6 ± 15.84 mg. For the LV, the number of pre-anal myomers was 28.65 ± 4.7; the post-anal was 23.85 ± 4.27, with a total of 52.47 ± 8.34; for J the myomers were not visible. This information is essential for ecological and productive purposes in B. moorei.

Despite being a tropical species, Nile tilapia is farmed in many subtropical regions worldwide, including southern Brazil, China, and Egypt, where production is hindered during the colder months of the year. This review aimed to identify and synthesize the main aspects that affect cold tolerance in Nile tilapia. There is sufficient evidence in the literature to show that modulation of dietary lipid amount and profile, for example, adding long chain n-3 fatty acids, can be vital for improving the physiological response of fish to cold. However, outdoor studies to validate these findings are yet needed. It is also important to understand how lipid metabolism and dietary supplementation of key compounds that improve membrane function, such as phospholipids and cholesterol, affect cold tolerance in Nile tilapia. Husbandry practices, including the use of large fish, bio-floc technology, and strains more tolerant to low temperatures can also improve Nile tilapia cold tolerance; however, these factors should be investigated in combination with adequate nutrition.

The present study evaluated the effect of pure and protected sodium butyrate with palm oil and buffered solution supplemented in the diet of Nile tilapia Oreochromis niloticus on the performance parameters, hematological parameters and disease resistance during sexual reversion. Initially, the minimum inhibitory concentration (MIC) of sodium butyrate (Na-butyrate) against Aeromonas hydrophila or Streptococcus agalactiae under three different pH to determine the concentration of inclusion of Na-butyrate in the diet were analyzed. After that a total of 3150 newly hatched post-larvae were distributed in 21 tanks with 100 L of capacity on six treatments and one control, in triplicate: fish fed unsupplemented diet (control); fish fed Na-butyrate supplemented diet (Pure 0.25% and Pure 0.5%); fish fed Na-butyrate coated with palm oil (Oil 0.25% and Oil 0.5%) and fish fed Na-butyrate coated with buffered solution (Buffer 0.25% and Buffer 0.5%). After 28 days of feeding, zootechnical parameters, hematological parameters and resistance against A. hydrophila were verified. The MIC results showed that Na-butyrate had a better inhibitory effect in vitro at pH 6 and 6.6 than at pH 7, regardless of the microorganism. The addition of Na-butyrate at different concentrations and forms did not influence the sexual reversal process of tilapia. Yield and biomass gain showed an increment in fish fed Buffer 0.5% and Oil 0.5%. Moreover, fish fed Oil 0.5% had a better feed conversion ratio than the other groups. An increase in the red blood cells (RBC) and monocytes were observed in fish fed Buffer 0.5% and Oil 0.25% when compared to control group, while those fed Pure 0.25% and Oil 0.5% showed the lowest monocytes number when compared to Buffer0.5% and Oil0.25%. After challenge by immersion in A. hydrophila solution, no difference was found among the treatments for 14 days of observation, except for the nonchallenged fish that showed no mortality ensuring the effectiveness of the experimental infection. The use of coated Na-butyrate either in buffer or oil showed to be feasible to improve the zootechnical parameters of Nile tilapia during the sexual reversion period.

The study of digestive physiology is a crucial aspect enabling commercial aquaculture of Octopus vulgaris type II. Knowing the processes of digestion, absorption, and assimilation of nutrients and factors that modulate the digestive environment is fundamental for designing adequate diets based on the digestive capacity of the animals. In the present study, we characterized the activity of total proteases in the gastric juice and digestive gland in adult O. vulgaris type II both fasted and during the postprandial period, and evaluated their digestive dynamics. In vitro experiments showed this species had predominantly acidic digestion, with maximal proteolytic activity at pH 3–4 and temperatures of 50 °C and 70 °C. These results confirmed the carnivorous feeding habit and high adaptive capacity of digestive enzymes in this species. The digestion time was 400 min at 20 °C when the digestive tract was ready to receive its next meal. Digestion occurred in two stages: the first, at the beginning of digestion, with rapid passage of soluble nutrients along the digestive tract; the second, which was slower, and involved the digestion, absorption, and assimilation of more complex nutrients (proteins and lipids). The ingestion peak occurred at 200 min after feeding when proteolytic activity was maximal. This species uses proteins as its primary source of energy and mobilizes proteins before lipids during intracellular digestion, which is a different digestion pattern to other tropical and subtropical-temperate octopus species. This new information contributes to a better understanding of the digestive physiology of O. vulgaris type II and is essential for formulating specific commercial diets for its farming. Keywords: Cephalopod, Protease, Gastric juice, Digestive physiology, Aquaculture

Nile tilapia production worldwide is concentrated in the subtropics, where lower winter temperatures is a challenge for the high productivity of tropical fish species. Adequate fatty acid nutrition of fish is a way to offset the lower temperature, as this nutrient is responsible for the structure, fluidity, and functionality of all cell membranes. However, there are still many gaps in Nile tilapia fatty acid nutrition, particularly at lower temperatures. In this study, three plant oil mixes and fish oil (FO) were fed to juvenile Nile tilapia at optimal (28 °C) or suboptimal (22 °C) temperatures for 9 or 12 weeks, respectively. The mixes of plant oils (coconut, olive, sunflower and linseed oils) were formulated to mimic fatty acid groups in FO, only varying the proportions between n-3 and n-6 polyunsaturated fatty acid (PUFA). They were named MIX-S, MIX-SL, and MIX-L since they contained an increasing amount of linseed oil (L) and n-3 PUFA as well as a decreasing amount of sunflower oil (S) and n-6 PUFA. Tilapia fed plant oil mixes exhibited similar growth at each rearing temperature. However, plant oil mixes led to lower daily weight gain than FO, except for MIX-S, which was comparable to FO when tilapia were fed at 22 °C. Feed efficiency and protein utilization were similar at 28 °C, but at 22 °C, the highest values were obtained in fish fed the FO diet. As expected, apparent net utilization of n-3 and n-6 PUFAs was higher when these groups of fatty acids were scarce in the diets. The body fatty acid profile of tilapia was influenced by dietary oil sources, but among the fish fed plant oils, total PUFA and total LC-PUFA were similar within each rearing temperature. Additionally, PUFA retention and conversion to higher chain length homologues in Nile tilapia seemed to be a strategy of adapting to lower temperatures. Our main finding is that changes in the n-3/n-6 PUFA ratio in diets with plant oil mixes do not alter Nile tilapia growth or feed efficiency at either 28 °C or 22 °C rearing temperatures. However, when compared to the diet with fish oil that was rich in LC-PUFA, plant oil diets resulted in lower growth. Plant oil mixes led to similar feed efficiencies as fish oil at 28 °C but not at 22 °C.

This study evaluated the inclusion of Aurantiochytrium sp. (ALL‐G‐RICH™), a source of docosahexaenoic acid (22:6 n‐3, DHA), in the diet of Nile tilapia and its effect on growth performance indexes and body composition. Fish (initial mean weight 8.35 ± 0.80 g) were fed different dietary inclusion levels of ALL‐G‐RICH™: 0.00, 0.05, 0.10, 0.20, and 0.40 g/kg and a control diet using cod liver oil (CLO), to provide DHA content comparable to the inclusion of 0.10 g/kg ALL‐G‐RICH™. Although there was no significant effect (p > 0.05) on weight gain, specific growth rate, feed conversion, protein retention rate, and proximal body composition, the inclusion of ALL‐G‐RICH™ in the Nile tilapia diet influenced positively the fatty acid profile in the body, resulting in a high DHA concentration. CLO‐fed fish accumulated significantly more DHA compared to those fed 0.10 g/kg ALL‐G‐RICH™ (p

In order to reduce disease outbreaks in shrimp aquaculture, biosafe farming practices have been created, such as the biofloc system and the use of feed additives to improve shrimp immune response and growth performance. Many studies with feed additives have tested probiotics in biofloc rearing systems; yet to date, no studies have reported on the use of prebiotics in the feed of farmed shrimp in biofloc systems. Moreover, the effects of mannoprotein (MP) prebiotics on shrimp and shrimp farming are also unknown. Therefore, this study aimed to evaluate the effects of dietary supplementation with mannoproteins (MP) on the performance, immune response, and midgut intestinal villi of L. vannamei raised in a biofloc system. Three diets with different MP concentrations were formulated (0.02%; 0.08%; 0.12%) and one control group without MP additive. The experiment utilized 12 experimental units (800 L) stocked with 400 shrimp/m3, with 3.64 ± 0.07 g of initial weight, in triplicate. Shrimp were fed four times per day, and both histology of the midgut and growth indices were assessed after 65 days. Intestinal villi presented a larger internal surface area in animals that were fed dietary supplements of 0.08% and 0.12% MP (p

espanolUna clasificacion de larvas de peces considera dos tipos: altriciales y precociales, asociadas al desarrollo temprano en relacion con la cantidad de yema disponible en el saco vitelinico. La etapa larval tiene como principal objetivo la obtencion de nutrientes para su ontogenesis. Para su comprension, estudios morfologicos, asociados a respuestas enzimaticas, deben ser realizados. Teniendo en cuenta que la larvicultura es el cuello de botella de los sistemas de produccion en acuicultura, se pretende abordar esta revision con el fin de comprender las relaciones entre el ambiente y los cambios que ocurren en la transformacion de larvas a juveniles, con el fin de asegurar el exito en la fase mas compleja en la vida de los peces. EnglishA classification of fish larvae considers two types, altricial and precocial; associated with early development in relation to the amount of yolk available in the vitellinic sac. The main objective of the larval stage is to obtain nutrients for their ontogenesis; for their understanding morphological studies, associated with enzymatic responses, must be carried out. Given that the larviculture is the bottleneck of production systems in aquaculture is intended to address this revision in order to understand the relationships between the environment and the changes occurring in the transformation of larvae to juveniles, in order to ensure success in the most complex phase in the life of the fish. portuguesUma classificacao de larvas de peixes considera dos tipos: altricial e precocial, associados ao desenvolvimento inicial em relacao com a quantidade de gema disponivel no saco vitelinico. O estagio larvario tem como objetivo principal a obtencao de nutrientes para sua ontogenese. Para a sua compreensao, estudos morfologicos, associados a respostas enzimaticas, devem ser realizados. Tendo em conta que a larvicultura e o gargalo dos sistemas de producao e, a aquicultura, pretende-se abordar este artigo com o fim de compreender as relacoes entre o ambiente e as mudancas que ocorrem na transformacao de larvas para juvenis, assim assegurar o sucesso na fase mais complexa na vida dos peixes.

The effect of increasing amounts (0%, 25%, 50%, 75%, and 100%) of dietary supplementation with an organic micromineral complex (Fe, Zn, Cu, Mn, and Se) on antioxidant defenses and mineral deposition in tissues of Nile tilapia juveniles was evaluated, where 100% supplementation represented the average adopted by the feed industry in Brazil. Fish (initial weight 23.93 ± 0.80 g) were fed until apparent satiation twice a day for 56 days. The maximum deposition of Fe and Zn in the hepatopancreas occurred in fish given approximately 50% supplementation, whereas the deposition of Mn and Se increased linearly with the inclusion of the complex. The activity of catalase and superoxide dismutase in the hepatopancreas decreased in fish fed the 50% dose, when compared to those not receiving mineral supplementation or those receiving higher doses. Glutathione peroxidase (GPx) activity in the hepatopancreas increased as the dietary Se concentration increased. However, the concentration of metallothionein in the hepatopancreas showed an inverse relationship to the increase in dietary supplementation of the organic mineral complex. There was no relationship between the doses of organic micromineral supplementation and the activities of GPx, reduced glutathione, non-protein thiols, or protein carbonylation. However, diets supplemented with 50% to 100% promoted greater GPx activity when compared to the 0% supplemented diet. Supplementation with intermediate doses of organic microminerals, approximately 50% of that used in commercial tilapia diets, promoted the homeostasis of metal metabolism, especially for Fe and Zn.

Resí­­duos de pescado processados na forma de silagem podem se constituir em uma alternativa ao uso de farinha de peixe (FM). Neste estudo caracterizou-se a composição e qualidade da silagem ácida produzida a partir de ví­­sceras de atum (TV) e determinou-se a digestibilidade dos nutrientes deste produto para jundiá Rhamdia quelen, utilizando-se o óxido de í­­trio como marcador inerte em delineamento completamente casualizado. Ao final de trinta dias, 61,74% da proteí­­na bruta da TV estava solubilizada. A silagem ácida de TV apresentou boa composição nutricional (alta proteí­­na e bom perfil de aminoácidos e de ácidos graxos essenciais) e qualidade microbiológica satisfatória. A digestibilidade da proteí­­na bruta foi similar (88,52%) para TV e FM, mas a da matéria seca foi maior (P

This study investigated the muscle quality of the shrimp Litopenaeus vannamei fed on a diet containing different proportions of mealworm meal (MW) (0, 25, 50, 75 and 100%) as a substitute for fishmeal, which is the normal diet used in shrimp commercial production. The proximate composition, fatty acid profile, colour and texture of the shrimps were evaluated. Moisture, protein, and ash content of shrimp muscle were not significantly altered when fishmeal was replaced by MW (p>0.05). However, the replacement resulted in a linear increase in lipid content (p

A six-week growth trial was performed to estimate the dietary protein requirements for maximum growth of juvenile Brazilian sardine (Sardinella brasiliensis) based on growth performance, feed utilization, body composition and digestive enzyme activity. Six isoenergetic diets were formulated to contain protein levels that increased from 250 to 500 g/kg. Each diet was randomly assigned to triplicate groups of 160 fish with mean initial body weight of 0.93 ± 0.13 g, which were fed four times a day to apparent satiation. Growth tended to increase with the increase in the dietary protein level up to 400 g/kg. Total protein intake was indirectly correlated to apparent protein utilization. No significant differences in whole-body composition were found between fish fed the different protein levels. Acid protease and neutral lipase activities did not show significant differences among the different protein dietary groups. Alkaline protease activity increased in fish fed up to 350 g/kg of protein and amylase activity in fish fed up to 400 g/kg. Using polynomial regression, 367 g/kg was estimated to be the optimum dietary protein requirement for maximum weight gain of juvenile Brazilian sardines.

Mealworm meal (MM) was evaluated for its potential as a future protein source for the farmed shrimp Litopenaeus vannamei . The apparent digestibility coefficients (ADC) were determined using a reference diet and a test diet that contained 85% reference diet and 15% MM, both contained 0.5% chromic oxide as an inert marker. Subsequently, considering the digestible values of MM, after six weeks of culture under clear water using five diets containing different levels of fishmeal replaced by MM (0%, 25%, 50%, 75% and 100%), the growth parameters and the whole shrimp body composition were evaluated. The values of the ADC were: 45.9% for dry matter, 66.5% for energy and 76.1% for crude protein while the ADC for essential amino acids ranged from 72% to 86%. Methionine was the first limiting amino acid in MM. Weight gain, specific growth rate, feed intake, feed conversion, survival and protein retention were not affected when fishmeal was replaced by MM (P > 0.05). The protein content of the shrimp body showed no significant differences (P > 0.05) between the treatments. However, lipid content of the shrimp body increased from 1.13% to 1.88% when fishmeal was replaced by MM. These results suggest that mealworm meal can be utilized as an alternative protein source for L. vannamei juveniles, although methionine should be added as a supplement.

Nile tilapia farming occurs in tropical and subtropical climate areas worldwide but information about dietary fatty acid requirements of Nile tilapia, particularly when raised at suboptimal temperature, are scarce. Previous studies with Nile tilapia failed to detect growth differences at suboptimal growth temperatures. Therefore, the objective of this study was to estimate the dietary requirement of α-linolenic acid (α-LNA, 18:3n − 3) of juvenile Nile tilapia, when raised at 22 °C. Increasing levels of linseed oil were added to a mixture of vegetable oils, yielding the following concentrations of α-LNA: 0.03, 0.21, 0.37, 0.67 and 0.99% of diet dry weight. The basal diet was formulated with semipurified ingredients and contained 5% lipid. Juvenile tilapia (10.6 ± 0.09 g) were fed the experimental diets twice daily until satiation for 14 weeks. The average water temperature throughout the experimental period was 22.12 ± 0.17 °C. The increase in dietary α-LNA significantly affected daily weight gain, specific growth rate, feed efficiency and daily feed intake. Total n − 3 fatty acid content in muscle showed a significant linear response to dietary α-LNA. Likewise, an accumulation of muscle linoleic acid (18:2n − 6) was directly related to the increase in dietary α-LNA, while n − 6 long-chain polyunsaturated fatty acids (LC-PUFA) decreased. The dietary requirement of α-LNA estimated for juvenile Nile tilapia reared at 22 °C was 0.70% diet for maximum weight gain and 0.68% for maximum feed efficiency. Statement relevance Nile tilapia, a tropical species, has been considered for aquaculture in subtropical regions, but its nutritional requirements under suboptimal temperatures are unknown. The present study shows that the α-linolenic requirement for this species under 22 °C is slightly higher than in 28 °C. Therefore, we suggest the increase in the α-linolenic levels in the diet for Nile tilapia during the cold seasons.

Five sources of dietary fatty acids (fish, linseed, sunflower, olive and coconut oils) were evaluated in juvenile Nile tilapia in two trials: at optimal (28°C) and suboptimal (22°C) temperatures lasting 9 and 12 weeks, respectively. At 28°C, there was no clear effect of dietary source on fish growth, but at 22°C, the highest daily weight gain occurred in fish fed sunflower, linseed and fish oil. Feed efficiency and apparent net protein utilization increased as the amount of unsaturated fatty acids, especially n-3 polyunsaturated fatty acids (PUFA), in the diet increased. Coconut oil, which is rich in saturated fatty acids (SFA), led to the worst growth results, especially at 22°C, with the lowest weight gain, feed intake and feed utilization by tilapia. The body fatty acid profile, in % of total fatty acids, was dependent on diet composition. However, for all treatments, PUFA body content increased with the decrease in temperature, but SFA and monounsaturated fatty acids remained the primary contributors to the body profile. Either fish oil or vegetable oil may be used as sources of dietary fatty acids for Nile tilapia, but at suboptimal temperatures, a dietary source containing more PUFA and less SFA improves performance.

This study aimed to isolate a potential probiotic amylolytic strain from the gut of jundiá catfish to improve carbohydrate digestibility in fish. Two of 31 strains isolated from the foregut of Rhamdia quelen were able to grow on starch-agar medium and were considered amylolytic. The strain that presented higher amylolytic potential, based on a qualitative amylase assay, was chosen. The strain was phenotypically characterized and analysed to determine bile and pH tolerance and extracellular quantitative amylase activity. The probiotic candidate, identified as Aeromonas veronii, showed the ability to survive stresses from a range of pH and bile salt conditions and secreted an interesting enzymatic profile, which may exhibit a synergistic effect when combined with the enzymes secreted by the jundiá catfish, improving carbohydrate digestion in the host. The results demonstrated the potential of A. veronii to improve the digestion process in jundiá by providing exogenous enzymes for the breakdown and absorption of nutrients.

The objective of this work was to evaluate the performance of Litopenaeus vannameifed different levels (0, 25, 50, 75, and 100%) of soybean protein concentrate (63.07% crude protein, CP) to replace fish meal-by product (61.24% CP). The study was conducted in clear water in fifteen 800 L tanks equipped with aeration systems, constant heating (29 ºC), and daily water exchange (30%). Each tank was stocked with 37.5 shrimp/m3 (3.03±0.14 g). Feed was supplied four times a day, at 6% of the initial biomass, adjusted daily. After 42 days, the weight gain of shrimp fed diets with 0 and 25% protein replacement was higher than that observed in shrimp fed 100% replacement, and there were no differences among those fed the other diets. Feed efficiency and survival did not differ among shrimp fed different protein replacements. There was a negative linear trend for growth parameters and feed intake as protein replacement with soybean protein concentrate increased. Fish meal by-product can be replaced by up to 75% of soybean protein concentrate, with no harm to the growth of Pacific white shrimp.

Soy protein concentrate (SPC) was evaluated as a dietary replacement of animal protein sources (fish meal and poultry by-product meal) (APS) for juvenile Nile tilapia (Oreochromis niloticus). Apparent digestibility coefficients (ADC) of crude protein (CP) and dry matter (DM) were evaluated by feeding tilapia an experimental diet composed of 69.5% reference diet, 30% SPC, and 0.5% chromic oxide as inert marker. Apparent digestibility coefficients were 96.57% for CP and 76.84% for DM. In a feeding trial, increasing levels of dietary SPC (0, 33, 67, and 100%) replaced APS and were fed to tilapia juveniles (10.0 ± 0.18 g) for 60 days. Daily weight gain, specific growth rate, protein retention, feed conversion, body composition and liver histology were not significantly (P>0.05) affected by protein replacement. A second feeding trial compared tilapia’s growth performance when SPC was supplemented with methionine and threonine (100% SPC+aa, 100% SPC, and 0% SPC) as well as CP and DM digestibility. The amino acid supplementation of SPC significantly increased tilapia daily weight gain. Diets containing 100%SPC and 100% SPC+aa promoted higher protein ADC values than diet containing only APS. However, DM ADC values were significantly higher in fish fed 0% SPC when compared to 100% SPC. Therefore, SPC can replace poultry by-product meal and fish meal in diets for Nile tilapia without compromising growth performance, protein retention, body composition, liver histology, and protein digestibility. However, SPC supplementation with limiting amino acids, such as methionine and threonine, is advisable since it further increases weight gain and protein digestibility.