Abstract
Relative values of hepatopancreas and intestinal weight to somatic weight were significantly higher in the tiger puffer Takifugu rubripes (puffer) than the red sea bream Pagrus major (bream). Relative values of intestinal length to body length were reversely high in the bream, indicating that the puffer have intestines with large diameters.
Feces of the fishes were periodically collected after feeding on a test diet with 0.5% Cr2O3. Small amounts of feces and fecal Cr2O3 were obtained in the puffer until 72 hours after feeding (hAF), but those in the bream showed a great change, reaching a peak at 8-12 hAF and decreasing rapidly thereafter.
Intestinal digesta of the puffer fed 1.5% body weight of the test diet fell gradually until 48 hAF. In the bream fed the same ration size of the test diet, gastric digesta fell markedly until 9 hAF, but intestinal digesta was maintained at a relatively constant and low level until 24 hAF. Moreover, apparent protein, fat, and sugar digestibilities in intestinal digesta of the puffer rose gradually and linearly from 8 to 32 hAF, however, those of the bream were already high at 3 hAF and then tended to fall slightly until 24 hAF.
The results suggest that the puffer, which do not have a stomach, conduct digestion and absorption more slowly than the bream, which have a stomach.
