Abstract: To investigate the effects of feeding and short-term starvation on the thermal and hypoxia tolerance of Clarias gariepinus, the critical temperature (CT_max and CT_min), lethal temperature (LT_max and LT_min), critical oxygen pressure (P_crit) and the loss of equilibrium (LOE) of experimental fish were measured at 25 ℃. The critical metabolic rate (MR_pcrit) and marginal metabolic rate (MR_LOE) were calculated. The results showed that both CT_max and LT_max decreased significantly, whereas both P_crit and MR_pcrit increased significantly after feeding (P<0.05). The CT_min, LT_min, LOE, and MR_LOE showed no variation between the feeding group and feeding control group. In addition, CT_max, LT_max and LT_min decreased significantly after starvation (P<0.05), while LOE was higher in starvation group than that in starvation control group (P<0.05). There was no significant difference in CT_min, P_crit, MR_pcrit, and MR_LOE between the starvation group and starvation control group. These results suggest that the heat and hypoxia tolerance of Clarias gariepinus were weakened by feeding digestion and short-term starvation stress, and that cold tolerance was enhanced after short-term starvation, which is related to the changes in metabolic rate and adjustments in some physiological functions of Clarias gariepinus during feeding digestion and starvation.

Key words: digestion, short-term starvation, thermal tolerance, hypoxia tolerance, Clarias gariepinus