Availability of Carbohydrate in Nutrition of Yellowtail

Abstract

In order to investigate the availabilities of α-starch and glucose in the nutrition of yellowtail Seriola quinqueradiata, the fish were fed on the diets containing α-potato starch and glucose at a level of 10% or 20% for 30 days. The 10% α-potato starch and 10% glucose groups showed no significant difference in the growth and feed efficiency. The growth of the 20% α-potato starch group w s similar to that of the 10% α-potato starch group, though the feed efficiency was ap-preciably low. However, the_20% glucose group exhibited the extremely low growth and feed efficiency. On the other hand, the percent absorption of glucose within 2h after the administra-lion of diets was considerably high as compared with that of α-potato starch, and the blood sugar levels were higher in the glucose groups than in the α-potato starch groups. Moreover, the gly-cosurla was recognized in the former groups, whereas it was scarcely detected in the latter groups. These findings indicate that the availability of glucose in yellowtail is lower than that of α-potato starch, as well as in carp Cyprinus carpio and red sea bream Chrysophrys major.