Rohu (Labeo rohita) is a freshwater fish extensively cultured in Asia. However, the optimal feeding regime for fish reared at high stocking density in relation to temperature has not yet established. The present study examined the feed intake, growth rate, feed utilization, body composition, activity of digestive enzymes, and levels of growth hormones to determine the optimal feeding frequency in relation to varying temperature. This study was conducted in two trials, trial I (high water temperature; summer) and trial II (low water temperature; winter). Each trial consisted of three groups, with fish stocked at a high density of 4.50 kg/m³ in each group. The three groups (HF1, HF2, HF3) of trial I were fed according to 2% (two rations/day), 3% (three rations/day), and 4% (four rations/day) of their body weight, respectively. In case of trial II, its three groups (LF1, LF2, LF3) were also given feed according to 2% (two rations/day), 3% (three rations/day), and 4% (four rations/day) of their body weight, respectively. Each group in both trials had three replicates. The trial continued for 120 days, with 60 days for trial I (1^st June-31^st July) and 60 days for trial II (1^st October-30^th November). Fish exhibited better growth, higher levels of digestive enzymes activity, and hormones levels at higher temperature. Increase in weight gain was found to be in correlation with feeding frequency (4% > 3% > 2%) both during high and low temperature. The best feed conversion rate (FCR) was observed at a 2% feeding rate. Different temperatures and feeding frequencies did not affect the chemical composition of fish muscles. The levels of triiodothyronine, tetraiodothyronine, and growth hormone were higher at the 4% feeding rate at high temperature than other regimes. In conclusion, higher water temperatures (30.45±0.43°C) were effective in rearing rohu. Considering feeding rate, although a higher feeding rate (4%) resulted in maximum growth, but it reduced feed efficiency, as indicated by a higher FCR. Therefore, this study recommends a 2% feeding rate for rohu, administered twice a day at high stocking density, during both high and low temperature, which is also cost efficient and more sustainable strategy.

Keywords: Rohu; Feeding regime; Feeding ration; Feed conversion rate