The dietary total and available requirement of tryptophan of Nile tilapia fingerlings was determined using linear regression analysis. Six hundred fish (3.4 ± 0.0 g) were fed diets containing 296.4 g/kg of crude protein and 14.1 MJ/kg of digestible energy. Five extruded diets containing 2.5, 3.0, 3.4, 3.8 and 4.2 g/kg of total tryptophan were evaluated. Fish were fed four times a day during 45 days. Final body weight, weight gain, feed intake, feed conversion ratio and net protein utilization of fish fed Trp 3.4 and Trp 3.8 diets were improved compared to fish fed Trp 2.5 and Trp 4.2 diets. No significant differences in survival rate, whole‐body moisture and ash were observed. Whole‐body amino acid profile of fish fed different diets did not differ statistically (p > .05). Fish fed Trp 3.0 and Trp 3.4 diets showed higher tryptophan retention compared to fish fed Trp 2.5 and Trp 4.2 diets. Excepting blood glucose, no effects of dietary tryptophan on haematological parameters were observed. The dietary total tryptophan requirement of Nile tilapia fingerlings based on weight gain was estimated to be 3.4 g/kg (11.0 g/kg of dietary crude protein) or 3.0 g/kg of available tryptophan (11.0 g/kg of dietary digestible protein).

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Esse trabalhado teve como objetivo a elaboração de uma sopa instantânea com inclusão de farinha de peixes, avaliando a qualidade nutricional, microbiológica e sensorial. Foram desenvolvidas quatro sopas instantâneas, contendo diferentes farinhas de peixes (tilápia, tilápia defumada, tilápia defumada com salmão, e tilápia defumada com atum). Após a elaboração das farinhas estas foram adicionadas aos ingredientes da sopa, homogeneizados, embalados e analisados quanto a sua composição nutricional e microbiológica, depois preparada a sopa com adição de água quente para a análise sensorial. Todas as misturas das sopas e farinhas de peixe estavam dentro dos padrões microbiológicos para consumo. A mistura da sopa com inclusão de farinha de tilápia apresentou maior teor de umidade e menor valor calórico. As sopas com farinha de tilápia defumada e de tilápia defumada com salmão apresentaram maiores teores de lipídeos (6,90% e 6,89%, respectivamente) e de tilápia defumada com atum, o menor teor de cinzas. Não houve diferença para proteína e carboidratos, assim como, para a cor e para a textura das sopas. A mistura de sopa instantânea com farinha de tilápia defumada com atum teve pior aceitação no atributo aroma. O sabor, a impressão global e a intenção de compra foram piores para a sopa com inclusão de farinha defumada com atum. Conclui-se que as misturas de sopas instantâneas enriquecidas com farinha de peixe são nutritivas, com melhor aceitação para as sopas com farinha de tilápia, de tilápia defumada e tilápia defumada com salmão.

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This research was conducted to determine optimal dietary histidine requirement of grow-out Nile tilapia, Oreochromis niloticus, based on muscle development, expression of muscle-growth-related genes, and blood parameters. Fish (n = 288, initial body weight of 64.17±0.53 g) were fed extruded diets with graded levels of histidine (4.23, 5.44, 7.17, 8.91, and 11.57 g kg −1), containing approximately 289 g kg −1 crude protein and 3565 kcal kg −1 digestible energy. The study followed a completely randomized design with five treatments and four replicates each, for 65 days. There was a quadratic effect of dietary histidine on final body weight, feed conversion, and net protein utilization, and the best values were optimized at 8.09, 7.88, and 7.33 g kg −1 , respectively. Feed intake, hepatosomatic index, survival, body composition, and blood parameters of total protein, glucose, triglycerides, cholesterol, hematocrit, and hemoglobin were not affected by dietary treatments. Predominance of hypertrophic growth and higher mRNA levels of myogenin and MyoD were observed in fish fed histidine from 5.44 to 11.57 g kg −1 compared with fish fed histidine at 4.23 g kg −1. The mRNA expression of myostatin was not affected by dietary treatments. The dietary requirement of histidine for grow-out Nile tilapia was determined at 8.09 g kg −1 , considering growth performance, muscle development, and gene expression responses.