Influence of Feeding Rates on Digestion and Energy Flow in Tiger Puffer and Red Sea Bream

Abstract

The tiger puffer Takifugu rubripes (puffer) and the red sea bream Pagrus major (bream) were fasted or fed 1/4, 1/2, and 1 satiation of an artificial diet for 20 days, and digestive and absorptive ability and energy flow were composed. The puffer fed 1/2 and 1 satiation of the diet showed higher feeding rate, growth rate, feed efficiency, protein efficiency ratio, and protein retention than those of the bream fed under the same feeding protocols. Higher fat retention and protein digestibilities were obtained in the bream, however, no marked difference between the fishes was found in sugar and fat digestibilities, excepting the lowest fat digestibility of the puffer fed 1 satiation. Although the bream tended to show better digestable, metabolizable, and retention energy than the puffer, higher standard metabolizable energy was obtained in the puffer. Energy expenditure for heat increment plus voluntary activity was less in the puffer. These suggest that low energy expenditure for heat increment plus voluntary activity in the puffer, which do not have a stomach, compensates for poorer protein digestibilities than those in the bream, which have a stomach.