A reference diet for nutritional studies of the giant tiger prawnPenaeus monodon

Critical evaluation of the nutrient requirements of an animal requires the use of a purified reference diet. In this study, the effects of either a purified reference experimental diet, a practical experimental diet and an imported commercial diet on the growth and nutritional condition of the prawn Penaeusmonodon were compared. The reference diet, based on widely available ingredients of consistent and known nutrient content, supported excellent prawn growth when fed either ad libitum or subsatiation (≈ 75% of the mean initial satiation intake). In a 6-week experiment, growth (as percentage increase in weight, ± SEM) of the prawns fed ad libitum differed significantly (P < 0.05) between each diet in the order: practical (142 ± 10%), reference (121 ± 9%) and commercial (91 ± 16%). Growth for the reference diet fed subsatiation was 116 ± 4%, and was not significantly (P > 0.05) different from that obtained with the same diet fed ad libitum. Dry matter food conversion for the reference diet was significantly (P < 0.05) better when fed subsatiation (1.58 ± 0.08) rather than ad libitum (2.08 ± 0.06) and better than that obtained with either the practical (3.40 ± 0.15) or commercial (3.02 ± 0.28) diets, which were not significantly (P > 0.05) different from each other. The lipid content (mg g–1 of prawn) of the digestive gland of prawns fed ad libitum was similar for reference, practical and commercial diets (6.03 ± 0.38, 4.92 ± 0.90 and 4.92 ± 0.95 mg g–1 of prawn, respectively), but significantly (P < 0.05) higher than that for the reference diet fed subsatiation (4.73 ± 0.38 mg g–1 of prawn).