-The objective of this study was to determine the apparent digestibility coefficients of energy, protein, and amino acids in protein ingredients by pirarucu juveniles. A test was conducted with six protein ingredients: meat and bone meal, fish meal, hydrolyzed feather meal, poultry by-product meal, soybean meal, and corn gluten meal. Three repetitions were used for each tested ingredient. A reference feed was used with 430 g kg −1 crude protein and 19.63 kJ g −1 gross energy. The test feeds consisted of the replacement of 30% of the reference feeds with the test ingredients. Chromium oxide was added to the feeds at 1 g kg −1 as an external marker. Eighteen juveniles with an average weight of 235±36 g were used. The best apparent digestibility coefficients of protein were found for fish meal, followed by the poultry by-product meal and meat and bone meal. However, except for gluten, all the tested ingredients presented protein digestibilities above 0.70. The crude energy apparent digestibility coefficient was higher for animal ingredients, above 0.75, than for vegetable ingredients, which presented values below 0.60. Pirarucu efficiently uses the protein from the tested ingredients, regardless of origin. However, it has a preferential ability to use the energy from animal ingredients.

The productive performance and the variable cost of production were evaluated for different feeding strategies for tilapia during the production cycle. A sample of 2,000 juvenile tilapia was distributed (23.55 ± 2.38 g) into five treatments and with four repetitions as follows: C (feed consumption to apparent satiety), R20 (beginning feed restriction when fish reached an average weight of 20 g), R200 (beginning feed restriction when fish reached an average weight of 200 g), R400 (beginning feed restriction when fish reached an average weight of 400 g) and R600 (beginning feed restriction when fish reached an average weight of 600 g). The fish were given extruded commercial feed containing 34% crude protein until they reached a weight of 200 g, at which time they received feed containing 32% crude protein. Monthly biometrics were performed in order to determine the food restriction starting point, which was one day of restriction followed by six feeding days. The following parameters were evaluated: water quality, productive performance variables, the variable costs of production and excreted nitrogen. The results were subjected to analysis of variance, and the means were compared using Tukey's test (5% significance). No statistical differences were observed in final weight, weight gain, feed consumption, feed conversion or survival. The fish from the R20 treatment had the lowest variable cost of production (g fish -1 ) and the lowest nitrogen excretion into the water. This suggests that feed restriction from the early stages of life does not compromise the productive performance and contributes to reducing the variable costs and the quantity of nitrogen excreted into the environment. Thus, a one-day per week feed restriction strategy can be applied from the earliest stages of life without compromising the productive performance or body composition of Nile tilapia. This strategy can also reduce variable costs of production by means of reducing relative labour and feed costs. (23,55 ± 2,38 g) em cinco tratamentos e quatro repetições: C (consumo até a saciedade aparente), R20 (início da restrição quando peixes atingiam peso médio de 20 g), R200 (início da restrição quando peixes atingiam peso médio de 200 g), R400 (início da restrição quando peixes atingiam peso médio de 400 g) e R600 (início da restrição quando peixes atingiam peso médio de 600 g). Os peixes foram alimentados com ração comercial extrusada com 34% de proteína bruta até atingirem 200 g, quando passaram a receber ração contendo 32% de proteína bruta. Foram realizadas biometrias mensais para determinação do início da restrição alimentar, que foi de um dia de restrição seguido de seis dias de alimentação. Foram avaliados os parâmetros de qualidade da água, variáveis de desempenho produtivo, os custos variáveis de produção e o nitrogênio excretado. Os resultados obtidos foram submetidos à análise de variância e as médias foram comparadas pelo teste Tukey (5%). Não foram verificadas diferenças estatísticas no peso final, ganho de peso, consumo de...

Knowledge on the nutritional value of feed ingredient is an important step in the formulation of diets in order to maximize animal productivity. Thus a study was conducted to determine the apparent digestibility coefficients (ADC) of dry matter (ADCDM), crude protein (ADCCP), gross energy (ADCGE) and amino acids (ADCAA) of conventional feed ingredients for juvenile silver mojarra (13.0 ± 3.23 g). The study was conducted in the laboratory for nutrition and feeding of fish (AQUANUT), using 80 silver mojarra collected in nature, which were kept in digestibility aquaria for a period of 21 days. The following ingredients were evaluated: fish meal, soybean meal, corn meal, corn gluten meal, rice bran, wheat bran and starch, which substituted 30% of a reference pelletized diet with 325.00 g kg crude protein and 3,692 Kcal kg -1 gross energy. Additionally 1.0 g kg -1 chrome oxide was added to each diet as a marker. The excreta were obtained using three repetitions for each tested ingredient, which were dried for further analyses. The soybean meal showed the best ADCDM value (67.45%), followed by the other ingredients. There was no significant difference between the soybean meal (95.16%), fish meal (92.97%) and the corn meal (91.90%) for the best ADCCP coefficients. The ADCGE for soybean meal and maize meal were 65.23% and 60.31%, respectively, followed by fish meal (51.85%). The results demonstrate that silver mojarra can digest animal protein as well as that of vegetal origin. Silver mojarra can also efficiently digest and absorb some of the main amino acids of fish, such as lysine, methionine and threonine, from the same studied ingredients. Key words: Acará-peba. Amino acid. Mariculture. Nutritional value. ResumoO conhecimento do valor nutritivo de alimentos é um passo importante na formulação de dietas para maximizar a produtividade animal. Foi realizado um estudo para determinar os coeficientes de digestibilidade aparente (CDA) da matéria seca (CDAMS), da proteína bruta (CDAPB), da energia bruta (CDAEB) e dos aminoácidos (CDAAA) de ingredientes convencionais para juvenis de carapeba (13 ± 3,23 g). O estudo foi realizado no Laboratório de Nutrição e Alimentação de Peixes (AQUANUT), utilizando 80 exemplares de carapeba, coletados na natureza, que foram mantidos em aquários de digestibilidade no período de 21 dias. Foram avaliados os seguintes ingredientes: farinha de peixe, farelo de soja, fubá de milho, farelo de glúten de milho, farelo de arroz, farelo de trigo e amido, que substituíram 30% de uma dieta referência peletizada com 325,00 g kg -1 de proteína bruta e 3,692 Kcal kg -1 de energia bruta, utilizando 1,0 g kg -1 óxido de cromo como marcador. As excretas foram obtidas utilizando três repetições para cada ingrediente testado, e após a secagem foram realizadas as análises laboratoriais. O farelo de soja apresentou o melhor resultado para o CDAMS (67,45%) seguido pelos demais ingredientes. Para o CDAPB não houve diferença significativa entre o farelo de soja (95,16%), a farinha de peixe (92,97%) e o fub...

The performance and hematologic responses of juvenile piavuçu fish (Leporinus macrocephalus) that were fed with feeds containing garlic, cinnamon, and yeast before being submitted to stress from capture were evaluated. The experiment was conducted in the Fish Nutrition Laboratory (Laboratório de Alimentação e Nutrição de Peixes), where 192 piavuçu juveniles (3.09 ± 0.8 g) were distributed among 16 tanks (170 L), with a density of 12 fish per tank. The experiment consisted of four treatments and four repetitions. Treatments included the addition of 10 g Kg -1 garlic, 10 g Kg -1 cinnamon, and 9x10 5UFC g -1 of Saccharomyces cerevisiae yeast, in addition to a control diet that included no additives. The performance, body indices, and survival of the fish were evaluated. After the performance test, the fish were submitted to stress from capture, and the effect of the additives as a stress reducer was evaluated through hematologic analyses. Better weight gain and feed conversion ratios (P≤0.05) were observed in the fish fed with diets containing garlic and cinnamon; however, no alterations were noticed in the nutritional composition of fish carcasses, regardless of the treatment they were submitted to. A reduction in the number of leukocytes of the fish submitted to stress in all treatments was verified. It is possible to conclude that diets supplemented with garlic and cinnamon at the level of 10 g Kg -1 led to a better performance, while not influencing the hematologic standards after the stress from capture. canela e 9x10 5 UFC g -1 de levedura Saccharomyces cerevisiae e uma dieta controle, sem a inclusão de aditivo. Foram avaliados o desempenho, índices corporais e sobrevivência dos peixes. Após o ensaio de desempenho os peixes foram submetidos ao estresse de captura e o efeito dos aditivos como mitigador do estresse foi avaliado por meio de análises hematológicas. Observou-se melhor ganho de peso e conversão alimentar (P≤0,05) nos peixes alimentados com as dietas contendo alho e canela, porém não foram observadas alterações na composição bromatológica da carcaça em nenhum dos tratamentos. Verificou-se redução nos números de leucócitos dos peixes submetidos ao estresse em todos os tratamentos. Conclui-se que dietas suplementadas com alho e canela ao nível de 10 g Kg -1 apresentaram melhor desempenho, não influenciando nos parâmetros hematológicos após o estresse de captura.

O presente estudo avaliou o efeito da relação energia:proteína da dieta no desempenho de juvenis do apaiari, Astronotus ocellatus. Trinta e dois juvenis (4,99 ± 0,63 g; 2,64 ± 0,74 cm) foram alojados em 32 tanques rede de polietileno com sistema de filtragem mecânica e biológica, aeração constante e fotoperíodo de 12:12 horas. Os tratamentos consistiram em quatro dietas isoenergéticas (3.850 kcal kg-1), com níveis crescentes (38%, 43%, 48% e 53%) de proteína bruta (PB), obtendo-se, dessa forma, relações energia: proteína de 7 (T-1), 8 (T-2), 9 (T-3) e 10 (T-4) kcal g-1 de energia digestível (ED). As dietas foram administradas diariamente, até a saciedade aparente, as 10 e 16 horas, durante 75 dias, em delineamento experimental inteiramente ao acaso (DIC). Os dados obtidos foram submetidos à análise de variância e teste de Tukey ao nível de 5% de probabilidade. Ao fim do experimento, o tratamento dois apresentou o melhor valor para o ganho de peso acumulado (10,92 ± 0,3 g), diferindo significativamente dos demais (P<0,05). A média geral entre os tratamentos para conversão alimentar aparente (1,8), taxa de crescimento específico (1,93%), eficiência protéica (1,82%) e sobrevivência (100%), não diferiram significativamente entre os tratamentos (P>0,05). Pode-se sugerir, com base nos resultados obtidos, que a relação de 8 kcal g-1 de PB atende as exigências nutricionais de juvenis do A. ocellatus, proporcionado melhor desempenho zootécnico.