Influence of Dietary Rice Grain Replaced from Corn on Serum Concentrations of Amino Acids in Young Chickens

At present, in Japan, it seems to be very valuable to increase the production of self-sufficient forage crops to reuse rice fields that have been abandoned and are no longer cultivated. Furthermore, the advantage of increased production of self-sufficient forage crops has the potency to overcome the higher costs of imported feedstuffs like corn grain and soybean meal from oversea. In the present study, therefore, ground corn grain was substituted for rice grain in diets, and the influence of dietary rice grain with 3 types of particle size, i.e. unhulled rice grain, rice grain ground with 2 mm of particle size and powder rice grain, on growth performance and serum amino acid concentrations was examined. Throughout the experimental period, body weight gain in chickens fed a diet containing 60% of unhulled rice grain was the lowest of all. When half (30% in diets) of corn was substituted for unhulled rice grain, body weight gain was not affected by feeding unhulled rice grain. Body weight gain of chickens given either ground or powder rice grain was similar to that of birds fed a 60% corn diet. There were no significant differences in feed intake among all dietary treatments. When chickens were fed a diet containing unhulled or ground rice grain, gizzard was heavier than that of birds fed a 60% corn diet. Serum concentrations of isoleucine and valine were increased by feeding diets including 60% of rice powder, and serum isoleucine concentration significantly correlated to the change in body weight gain. From these results, it was concluded that 60% of ground (<2 mm) rice grain, 60% of powder rice grain and 30% of unhulled or ground rice grain were comparable to diets containing 60% of ground (<2 mm) corn to attain the appropriate body weight gain.