FIT Tambaqui: potencializando o crescimento muscular e a qualidade da carne através do exercício de natação

Abstract

Sustained swimming exercise in fish has been proposed as a strategy to improve aquaculture productivity, as it is associated with greater weight gain, improved feed conversion, modulation of muscle growth, and changes in flesh composition. This study evaluated the effects of different swimming velocities on growth performance, morphometry, biometric indices, hematobiochemical parameters, and muscle histology of juvenile tambaqui (Colossoma macropomum). Fish (160 ± 16.3 g; 20.5 ± 0.81 cm) were individually microchipped and randomly distributed into five circular tanks, exposed to water flow velocities of 10, 20, 30, and 40 cm s⁻¹, plus a control group without swimming, for 60 days. Fish subjected to 40 cm s⁻¹achieved the highest weight gain and eviscerated weight gain, whereas at 20 cm s ⁻¹ a reduction in feed intake was observed, limiting growth potential. Feed conversion ratio and survival did not differ among groups. Regarding morphometry, fish at 40 cm s⁻¹showed greater standard length and body width, with a linear increase in the CC/SL and BW/SL ratios, indicating exercise-associated phenotypic remodeling. The linear reduction in hepatosomatic and viscerosomatic indices, combined with the quadratic behavior of the visceral fat index, with a minimum estimated at 23.74 cm s⁻¹, indicated efficient mobilization of energy reserves to sustain physical effort, with metabolic reallocation toward lean tissue synthesis. Hematological parameters revealed adaptive physiological adjustments in hemoglobin and mean corpuscular hemoglobin concentration (MCHC), with no evidence of hematological impairment. In the biochemical profile, plasma glucose increased progressively with exercise intensity, peaking at 30 cm s⁻¹, while triglycerides exhibited a quadratic response, peaking at 10 cm s⁻¹ and then declining at higher intensities, reflecting greater lipid mobilization as metabolic demand increased. The reduction in cortisol at 40 cm s⁻¹ confirmed the absence of chronic stress and characterized a state of exercise-induced physiological conditioning. Swimming exercise significantly enhanced muscle hyperplasia, with fiber density peaking at 30 cm s⁻¹ (13,636 ± 408 fibers mm⁻²) and the exclusive presence of larger-caliber fibers (>30 µm) in that group. It is concluded that sustained swimming at 30-40 cm s⁻¹ represents the optimal intensity range for this species, combining maximum anabolic response, structural muscle remodeling, and physiological homeostasis.