Necessity of Dietary Cholesterol for the Freshwater Prawn

The cholesterol requirement of the freshwater prawn Macrobrachium rosenbergii, in terms of daily requirement (mg cholesterol/kg body weight/day), was assessed by the feeding experiment using casein-based diets with graded levels of supplemental cholesterol and by the analysis of carcass cholesterol. The prawn grew on a diet without supplemental cholesterol, and the body cholesterol was increased even in the prawn fed a cholesterol-free diet. However, the highest weight gain was obtained on the diet with 0.1 % supplemental cholesterol. These results indicated that the juvenile M. rosenbergii was capable of de novo cholesterol synthesis in contrast to other prawn species but required a dietary source of cholesterol for the maximum growth. When the diet containing 0.1% supplemental cholesterol was given to the prawn, it was suggested that dietary cholesterol was retained in the body at the rate of 0.065 mg/g body weight/day and the apparent body retention efficiency of dietary cholesterol was 83%. Based on the above results, when true feeding levels (or % ingestion of diet) are 7 to 3% of body weight, optimum dietary cholesterol levels for the juvenile M. rosenbergii are suggested to be 0.11 to 0.26% in diet under the experimental conditions adopted.