Abstract
In order to evaluate the involvement of taste in the decreased feed intake due to tea saponin, the preference for a diet containing saponin or cholesterol was studied in chicks given diet selection. When chicks were fed the basal diet added with 1% saponin ad libitum for 4-6h, feed intake decreased within 2h and the decrease in feed intake was became severer with time. Chicks given the choice between the basal and saponin-added diets for 12h selected the basal diet exclusively during 4-12h, but there were no significant differences in feed intake between the two diets during the first 4h. Chicks preferred the basal diet to the saponin-added diet when the two-choice preference test was prolonged to 8d. However, there were large individual differences in the feeding response among chicks; some chicks selected the basal diet from the start of the test, but others needed more time to select the basal diet. These individual differences were disappeared with fixing the feeder positions rather than changing the feeder positions every day. The deleterious effect due to tea saponin did not occur when equal amounts of cholesterol were supplemented to the saponin-added diet. However, chicks did not show the special preference for cholesterol, when they were given the choice between the basal diet and a diet containing 1% cholesterol for 12h or between the basal diet and a diet containing saponin plus cholesterol at 1% levels for 8d. These results suggest that chicks can recognize the presence of saponin, but taste is not a major determinant responsible for the depression in feed intake due to saponin.
