DIGESTIBILITY OF DIETARY COMPONENTS IN FISHES-II

The digestibility of several dietary proteins in rainbow trout was estimated by the method using inert reference substance, Cr2O8, as an indicator10). As shown in Fig. 1 and Table 2, the digestibility of dietary protein varied to some extent with days, size of fishes, and with the method of collection of feces in the same diet; the digestibilities determined by analyzing the feces excreted into pond water were higher than those estimated from the feces collected by stripping. Among animal diets tested, a white fish meal-protein showed the highest value in digestibility, whereas protein of a whale-meat meal showed considerably low value; this might be due to high content of protein in the test diet. In vegetable diets, protein of a soybean meal showed high value of digestibility.