Abstract The objective of this study was to evaluate growth and metabolic parameters of silver catfish fed with protein concentrates of sunflower meal (SMPC) and crambe meal (CrMPC). The study evaluated two levels of substitution, where 25 or 50% of animal protein was replaced with plant-based protein. A total of 300 silver catfish (14 ± 0.26 g) were used in five treatments and three replications, in fifteen 280-liter experimental units. The results were submitted to analysis of variance and the means of the control diet was compared to the remaining treatments by Dunnett’s test at 5% significance level. At the end of the trial, no differences were observed for the variables final weight and daily weight gain. However, minor feed conversion was observed in the groups Control and SMPC-25%. Metabolic parameters were analyzed in the plasma and liver, where no significant differences were found for any of the blood parameters analyzed. In the analyzed liver parameters (ammonia, protein, amino acids and ALAT), the liver protein content was lower in fish consuming SMPC-50%, CrMPC-50% and 25% CrMPC diets. The amino acids content was higher in fish receiving the SMPC-25% diet. It can be concluded that sunflower meal protein concentrate is better utilized by fish and more efficient metabolically than crambe meal. This study demonstrated that a newly developed protein concentrate SMPC and CrMPC can effectively replace 25% and 50% the animal protein in a diet free of FM.

Uma das demandas, na nutrição de peixes nativos, é a avaliação de fontes proteicas alternativas, que possam ser utilizadas em dietas. Este trabalho objetivou avaliar o crescimento e a composição corporal de juvenis de jundiá submetidos a dietas com diferentes níveis de farinha de minhoca. Um total de 300 exemplares, com massa inicial média de 15,6 ± 5,65 g, foram distribuídos em 15 tanques de polipropileno (250 L), durante 30 dias. O delineamento foi inteiramente casualizado, composto por cinco tratamentos (10%, 20%, 30% e 40% de inclusão de farinha de minhoca e uma dieta controle) e três repetições, com 20 peixes por unidade experimental. Os peixes foram alimentados duas vezes ao dia, recebendo 5% do seu peso vivo em ração dia-1. Ao final do período experimental, foram avaliados a massa final, comprimento total e padrão, taxa de crescimento específico, fator de condição e ganho em massa relativo. Também foi realizada análise de composição corporal, sendo determinadas a umidade, cinzas e gordura e proteína corporal, além da glicose sanguínea. Para a massa e comprimento total e padrão, não houve influência da adição de farinha de minhoca na dieta. Os níveis de inclusão de farinha de minhoca influenciaram a taxa de crescimento específico, ganho em massa relativo e o fator de condição dos peixes. A farinha de minhoca pode ser incluída em até 30%, na dieta de juvenis de jundiá, sem comprometer o crescimento dos peixes.

One of the greatest demands, concerning native fish nutrition, is the evaluation of alternative protein sources that can be used in diets. This study aimed at evaluating the growth rate and body composition of jundiá juveniles fed with different levels of earthworm meal. A total of 300 fish, with an average initial weight of 15.6 g ± 5.65 g, were distributed in 15 polypropylene tanks (250 L), for 30 days. A completely randomized design with five treatments (10%, 20%, 30% and 40% of earthworm meal inclusion and a control treatment) and three replications, totaling 20 fish per experimental unit, was used. The fish were fed twice a day, getting 5% of their body weight in feed day-1. At the end of the experimental period, the final weight, total and standard length, specific growth rate, condition factor and relative weight gain were evaluated. The body composition was also analyzed, being determined the rates of moisture, ashes and body fat and protein, as well as blood glucose. The weight and total and standard length were not influenced by the addition of earthworm meal to the diet. The inclusion levels of earthworm meal affected the fish specific growth rate, relative weight gain and condition factor. The earthworm meal can be added up to 30%, in jundiá juveniles diets, without compromising fish growth.