Tambaqui (Colossoma macropomum) is a freshwater fish species native to the Amazon and Orinoco river basins of South America. It is the most produced native species in Brazil and its total aquaculture production in 2021 was 262,370 t. The frugivorous regime of this species renders it particularly tolerant to dietary incorporation of fruits and seeds/nuts. Furthermore, carbohydrates are the least expensive dietary energy source and an interesting way to spare some dietary protein for growth. The present study evaluated the growth performance and lipogenesis indicators of juvenile tambaqui fed different energetic vegetal ingredients.
A total of 192 tambaqui (131.6 ± 1.9 g) were distributed in 24 aquaria and fed with 6 diets (4,000 kcal/kg) containing (30%): corn, sorghum, corn starch, wheat bran, rice bran and broken rice. Fish were fed for 57 days, until apparent satiation, in four meals a day. In the final biometry, the fish were weighed and measured, and blood aliquots were taken for later determination of metabolites in the blood. Then, the fish were sacrificed (eugenol, 10 g/L) for removal and weighing of visceral fat and liver. The experiment was carried out in a completely randomized design with 6 treatments and 4 replications. The results were submitted to ANOVA and Tukey’s test at 5%.
No mortality was recorded. No difference on growth performance of tambaqui was observed. On the other hand, fish fed corn starch displayed an increased lipogenesis. This is probably related to the concentration and availability of glucose from the starch.