Zootechnical performance and physiological responses of juvenile pirapitinga (Piaractus brachypomus) under different feeding rates and frequencies

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ABSTRACT: This study evaluated the effects of feeding rates and frequencies on performance and physiological responses of pirapitinga (Piaractus brachypomus). A total of 896 juveniles (1.32 ± 0.60 g) were stocked at a density of 1 fish/L for 40 days in a recirculating aquaculture system (RAS). Four feeding rates, 6% (T6), 8% (T8), 10% (T10) and 12% (T12) of biomass, and two feeding frequencies, F2, at 08:30 and 16:00, and F4, at 08:30, 11:00, 13:30 and 16:00, were tested in a 4x2 factorial arrangement with four replicates. The results for the first 30 days showed an effect of feeding rate on growth parameters, but no effect for feeding frequency in general. Between 30 and 40 days, weight gain, specific growth rate showed an effect of feeding rate, with T6 being superior. The viscero (VSI) and hepatosomatic (HSI) indices were affected, with the lowest values for T12. When fed with F2, the lowest hemoglobin was for T6, while there was no difference among feeding rates with F4. Higher triglyceride levels were recorded when fed with F2, T6, and T8, while the lowest was for T12. Blood glucose only had an effect of feeding frequency, with higher values for F2. Hematocrit, total protein, cholesterol, and mesenteric fat index (MFI) were not affected by feeding rate nor feeding frequency. A twice-daily feeding frequency proved sufficient for juvenile P. brachypomus, with an average initial weight of 1.3 g and reared in RAS, and a 12% biomass feeding rate was most efficient.

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