Assessment of cholesterol requirements in the prawn, Penaeus japonicus

Two feeding experiments were conducted to assess the quantitative cholesterol requirement of the juvenile prawn, Penaeus japonicus . The prawns were fed casein-based (experiment 1) and casein- or crab protein-based (experiment 2) diets with or without supplemental cholesterol. The daily increases in quantities of body cholesterol (mg kg⁻¹ prawn day⁻¹) at maximum growth and dietary cholesterol intake over a 40-day feeding period were determined. Prawns fed 5 g kg⁻¹ supplemental cholesterol, regardless of protein sources, gave the highest weight gain. Body retention efficiencies of dietary cholesterol (cholesterol retained × 100/cholesterol intake) vary among prawns fed 5 g kg⁻¹ supplemental cholesterol (diets 3, 5 and 7) but dietary cholesterol requirements expressed as mg kg⁻¹ body weight (BW) day⁻¹ were not significantly different (180 to 200 mg kg⁻¹ BW day⁻¹). Based on dietary cholesterol requirement, the optimum dietary cholesterol levels for the juvenile prawns were estimated in relation to feeding levels. When feeding levels were 3%, 5% and 7% of body weight, optimum dietary cholesterol levels were 5.0 to 6.0, 3.6 to 4.0, and 2.6 to 2.9 g kg⁻¹ of dry diet, respectively. The present study showed the advantages of determining daily cholesterol requirement (mg kg⁻¹ BW day⁻¹) at maximum growth through a factorial method in determining optimum dietary cholesterol levels in P. japonicus .