Dietary cholesterol requirement of juvenile mud crab Scylla serrata

The effect of dietary cholesterol on growth, molting frequency and survival of juvenile mud crab, Scylla serrata was investigated using semi-purified diets. Six isoenergetic and isonitrogenous diets containing 0.04%, 0.21%, 0.50%, 0.79%, 1.12% and 1.44% supplemental cholesterol were evaluated. Fifteen mud crabs per treatment, with an initial mean weight of 84.4 +/- 30.9 mg, were individually housed in 31 containers. After termination of the experiment, crabs fed the diets containing 0.5 and 0.79% cholesterol had significantly higher weight gain than those fed the other diets. Also, crabs fed the diet without cholesterol addition had the lowest survival and molting frequency among the groups. Survival of crabs fed cholesterol supplemented diets ranged from 73% to 93%. Diets containing more than 1.12% cholesterol had an adverse effect on mud crab growth. Based on percent weight gain data using broken-line analysis, the optimal dietary cholesterol requirement of juvenile mud crab was found to be approximately 0.51%. (C) 2000 Elsevier Science B.V. All rights reserved.