EFFECT OF FEEDlNG ON OXYGEN CONSUMPTION AND AMMONIA EXCRETION IN SILURUS MERIDIONALIS CHEN

The postprandial rates of oxygen consumption and ammonia excretion in the southern catfish (Silurus meridionalis Chen)were measured by a continuous2flow respirometer at 27.0±0.5℃The results showed that the standard oxygen consumption rate and ammonia excretion rate were 116.4±6.4 mgO2/kg/h and 6.9 ± 1.4 mgNH4+/kg/h,respectively1The postprandial changing patterns inoxygen consumption and ammonia excretion were similar eachother. After the testedfish ate itsfood the both rates increased drastically,and reached their maximum levels(358.8 ± 11.4 mgO2/kg/h and 76.1±2.5 mgNH4+/kg/h) in a short time(10.8±1.4h and 10.1±0.9 h),then decreased slowly towards to their resting levels1The durationfor the postprandial changes were 36.0±2.3h and 37.2±2.8h;the increased magnitud of oxygen consumption and ammonia excretion were 88.3±2.7 mgO2and 23.1±1.7 mgNH4+ compared with the standards,respectively1This study suggests that response in the rate of ammonia excretion to post2feeding should be relative closely to that in the oxygen consumption1And 79.4 % of energy expenditure for the specific dynamic action(SDA)in postprandial metabolism might be due to protein catabolism in the catfish