STUDY ON THE DIGESTION AND UTILIZATION OF FISH FECES BY SILVER CARP AND BIGHEAD FINGERLINGS

The feces of fishes was used to represent natural organic detritus and to feed the fingerlings of silver carp and bighead. The digestion and utilization of feces by both fishes were determined, from which the nutritional significance of natural organic detritus for both fishes was evaluated. In laboratory, fish feces egested by silver carp and bighead fed with Microcystis was collected as food for the fingerlings and its digestibility was determined. The growth of both fishes was also measured. The results are as follows.(1)Feeding feces for 10 days, the body weight of the experimental silver carp and bighead increased by 6.25?3.46% and 7.80?.18%, respectively.(2)The digestion rate of dry matter, protein, fat and carbohydrate of feces for both fishes are 58.54?.53% and 68.57?.98%, 74.49?.96% and 80.41?.02%, 90.23?5.33% and 84.24?6.96%, 49.14?0.67% and 60.36?1.29%, respectively, tively.Based on the nutritive value of feces and the ratio of energy conversion, it shows that fish feces plays a part in the nutrition of silver carp and bighead.