Effects of temperature on the growth, gastric emptying time, and oxygen consumption rate of mahseer (Tor tambroides) under laboratory conditions

The growth, gastric emptying time (GET), and oxygen consumption rate (OCR) of the commercially important freshwater mahseer, Tor tambroides, were evaluated under five temperatures (22 degrees C, 24 degrees C, 26 degrees C, 28 degrees C, and 30 degrees C) in triplicates with 15 fish per replication in a controlled laboratory condition. After 12 weeks, the body weight gain (BWG), specific growth rate (SGR), and daily growth rate (DGR) were measured. The highest BWG (7.25 +/- 1.14 g), SGR (0.71%+/- 0.10% day(-1)), and DGR (4.70 +/- 0.20 g day(-1)) were observed at 30 degrees C, whereas the lowest BWG (3.16 +/- 0.90 g), SGR (0.30 +/- 0.05% day(-1)), and DGR (1.77 +/- 0.30 g day(-1)) were observed at 22 degrees C (P<0.05). The fish were then slaughtered sequentially at different time intervals after initial feeding to obtain GET. Results showed that the shortest GET (10 h) was observed at 30 degrees C, whereas the longest (18 h) GET was at 22 degrees C. OCR was significantly high at 30 degrees C (5.5 +/- 0.53 mL O2L-1 h(-1)) but low at 22 degrees C (1.55 +/- 0.23 mL O-2 L-1 h(-1)). Based on the temperature quotient (Q(10)), the optimum temperature range for the respiration rate was between 28 degrees C and 30 degrees C. The findings of this study suggest that T. tambroides should be cultured at 30 degrees C because this temperature facilitates fast GET and best OCR, which may contribute to their fast growth. In summary, these findings would be useful to increase the production of T. tambroides in captive environment.