INFLUENCE OF FEEDING RATES ON DIGESTION AND ENERGY-FLOW IN TIGER PUFFER AND RED-SEA BREAM

The tiger puffer Takifugu rubripes (puffer) and the red sea bream Pagr us major (bream) were fasted or fed 1/4, 1/2, and 1 satiation of an ar tificial diet for 20 days, and digestive and absorptive ability and en ergy flow were composed. The puffer fed 1/2 and 1 satiation of the die t showed higher feeding rate, growth rate, feed efficiency, protein ef ficiency ratio, and protein retention than those of the bream fed unde r the same feeding protocols. Higher fat retention and protein digesti bilities were obtained in the bream, however, no marked difference bet ween the fishes was found in sugar and fat digestibilities, excepting the lowest fat digestibility of the puffer fed 1 satiation. Although t he bream tended to show better digestable, metabolizable, and retentio n energy than the puffer, higher standard metabolizable energy was obt ained in the puffer. Energy expenditure for heat increment plus volunt ary activity was less in the puffer. These suggest that low energy exp enditure for heat increment plus voluntary activity in the puffer, whi ch do not have a stomach, compensates for poorer protein digestibiliti es than those in the bream, which have a stomach.