Effect of dietary cholesterol on growth and survival of juvenile redclaw crayfish Cherax quadricarinatus under laboratory conditions

The effect of dietary cholesterol level on growth and survival of juvenile redclaw crayfish Cherax quadricarinatus was evaluated over a 10-week culture period. Five isoenergetic (430 kcal/100 g) and isonitrogenous (30% protein) diets, supplemented with 0%, 0.25%, 0.50%, 0.75% and 1.00% cholesterol were evaluated. Juvenile redclaw crayfish (0.06 +/- 0.02 g) were individually housed in plastic cages in 15-l, low case tanks in a climate-controlled laboratory, using a semiclosed recirculation system. Water temperature was maintained at 28 +/- 0.5 degreesC. Redclaw crayfish fed with 0.50% cholesterol diet had significantly higher weight gain than those from the other four treatments. Redclaw crayfish fed with diets without cholesterol supplementation had the lowest growth. Survival ranged from 90% to 100% and was not significantly different among treatments. The recommended dietary cholesterol level for optimum growth under these environmental conditions was 0.50%. (C) 2003 Published by Elsevier B.V.