Estudo sobre o crescimento do tambaqui (Colossoma macropomom) submetido à dieta suplementada com camu camu (Myrciaria dubia) em água corrente e aquecida

Abstract

This study investigated the growth of the tambaqui (Colossoma macropomum) (Cm), an caracid teleost in the Amazon region, in the laboratory. Juvenile fish were submitted to the simulation of the natural conditions of feeding, climate and running water, corresponding to the flood and dry periods of the Amazonian hydrological cycle. In the flood, its diet is predominant of fruits and seeds, the environment is mild (28 ± 2°C) and the current is higher (0.2 to 0.3 m/s). In drought, the feed is based on animal protein, there is no current and the average temperature rises (34 ± 2°C). Therefore, the aim of this study was to investigate the effects of Myrciaria dubia (Md) on the growth of Cm in the drought or flood simulations with respect to the mild (28 ° C) or heated (34 ° C), standing or running water (0,2 or 0.3m/s), and diet with higher (45%) or lower (32%) crude protein (CP) content. For this, juveniles of Cm were acclimatized (70 or 126 days) in tanks of (310 or 500 liters) according to the experimental protocol. Protocol I: diet with fractioned daily supply (3x/day) and supplemented with Md; crude protein (45 or 32%); running water (0.2 m/s) or stopped at 28 or 34°C; analysis of muscle contents of IGF1 and total lipids. protocol II: single or fractioned offer (3x / day); standing or running water (0.3 m/s), intercalated, (12 hours) or continuous; quantification of the cavity fat mass. The results are presented on average plus or minus the standard error of the mean and compared by ANOVA plus Bonferrone post-test. Correlation test for weight, length or cavity fat versus running water; in the conditions of single or fractional supply was performed to verify interrelations between the phenomena studied. A potentiation of body mass expansion rather than length occurred by the diet supplemented with Md in standing and heated water. In contrast similar potentiation occurred for running and heated water in the 45% CP diet. In turn, lower growth performance (weight and length) was observed in the group submitted to a 32% CP diet. The running water also potentiated the accumulation of cavitary and muscular fat of total lipids, suggesting that the swimming effort demands accumulation of potential energy possibly related to the preservation of protein anabolism, since the protein content in the muscle tissue was not altered. On the other hand, the single daily supply of food was not enough to maintain the resulting growth performance to sustained swimming (running water). In the fractioned supply, the group submitted to continuous running water showed the best performance, suggesting that sustained swimming in running water may be a determinant factor for the growth of Cm if it is offered a diet with high protein content, considering the warm environment as the most favorable. Finally, the increased IGF-1 content in the muscle confirms the participation of this growth factor as the final pathway of humoral regulation of muscle hypertrophy. Hypertrophy results in increased swimming effort, and, surprisingly, in response to diet supplemented by Md.