ENERGETIC METABOLISM IN MUSCLE OF TAMBAQUI JUVENILES Colossoma macropomum FED WITH DIETARY AÇAI Euterpe oleracea Mart
The development of feeds with bioactive compounds for the fish farm is relevant not only to satisfy the nutritional needs of the fish, but also to improve antioxidant capacity, bioenergetic status, growth promotion, and immune responses. The intake of antioxidants can modulate pathways and inhibit pro-oxidant processes in animal metabolism. The açai fruit (Euterpe oleracea) have high levels of polyphenols and unsaturated fatty acids - UFAs (mainly oleic acid and linoleic acid). In this study, the effects of lyophilized E. oleracea (LEO) were evaluated on total protein (TP), total cholesterol (TC), triglycerides (TG), glucose (GLU), glycogen levels (GL) and electron transport system (ETS) in the muscle of tambaqui Colossoma macropomum juveniles. The experiment was approved by the Ethics Committee of Animal of the Instituto Federal do Pará - IFPA (CEUA nº 3095220419). Fish (0.92 ± 0.01 g) were randomly distributed in 18 tanks (200 L; 50 fish/tank) and fed with a control feed and five diets with levels of inclusion of LEO at 0.00, 0.63, 1.25, 2.50, 5.00, and 10.0% (w/w). Fish were hand-fed four times a day at 10% of body weight for 30 days. All dietary treatments were performed in triplicate. The water quality parameters were maintained within the recommended ranges for the species. After this trial feeding, fish were sampled (n = 15/treatment) for the determination of the metabolic parameters mentioned. The data obtained were submitted to a linear mixed-effects model followed by Newman-Keuls post-hoc test (5%) for comparing the means.
None statistical differences were detected in energy reserves, except for muscle triglycerides, which declined by 40.52% from the inclusion of 0.63% LEO (17.5 ± 1.3 mg/dL) in the diet to control (29.5 ± 1.6 mg/dL). The ETS activity measures cellular metabolic potential. In this study, the açai inclusion elevated ETS activity in fish fed with LEO at 1.25% to 10.0% (13106.7 ± 1080.7 mg of O2/h.mg prot and 18133.1 ± 1458.9 mg of O2/h.mg, respectively), with significantly lower activity in the control (7436.1 ± 919.7 mg of O2/h.mg prot) and 0.63% LEO (7067.4 ± 800.8 mg of O2/h.mg prot) groups. The antioxidant and UFAs LEO profile possibly modulate metabolic pathways of C. macropomum , decreasing triglyceride storage on muscle by lipid oxidation induction, contributing to energy production. Moreover, the increased in ETS activity is possibly associated with polyphenol-triggered mitochondriogenesis processes. Therefore, the dietary administration from 1.25% LEO is recommended to optimize the energy efficiency of the organism and to favor physiological functions such as the growth of the skeletal muscle of the tambaqui.
