ABSTRACT
This study aimed to determine digestible methionine+cystine requirement of tambaqui juveniles in the early stage of development (3.03 ± 0.06 g) lasting 45 days. 160 tambaqui juveniles were distributed into DIC, with five treatments (methionine + cystine = 0.66; 0.73; 0.80; 0.87; 0.94%), four replications and eight animals per experimental unit. The basal diets were isonitrogenous (25% crude protein) and isocaloric (3200kcal.kg-1). The results were submitted to the homogeneity test, normality test, analysis of variance, and regression analysis. The physical and chemical parameters of water from the water recirculation system were within those recommended for the species. Digestible methionine+cystine levels did not influence (P>0.05) the survival, hepatosomatic index, visceral fat index and feed intake. However, weight gain and protein efficiency ratio exhibit a linear increase (P<0.05) with increase in methionine and cystine in the feed. Our results showed that the methionine + cystine levels for tambaqui were not fully met, and new studies are recommended.
Keywords:
amino acids; Caracídeos; Colossoma macropomum; nutrition
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