Development of a pelleted feed for juvenile tropical spiny lobster (Panulirus ornatus):: response to dietary protein and lipid

Critical to the development of a cost-effective feed for the tropical spiny lobster Panulirus ornatus is knowledge of its response to the protein and lipid (or energy) content of the feed. An experiment of 12 weeks duration was carried out to examine growth responses of juvenile lobsters to pelleted diets that provided six crude protein (CP) levels [320-600 g kg(-1) dry matter (DM)] and two lipid levels (nominally 60 and 100 g kg(-1) DM). Lobsters (mean initial weight of 1.8 g) were held in groups of nine or 10 animals in 24 x 350 L tanks, fed twice daily at a restricted level, and maintained at 28degreesC. Maximal growth responses occurred at dietary CP contents of 474 g kg(-1) for the 60 g kg(-1) lipid series and 533 g kg(-1) for the 100 g kg(-1) lipid series. A second experiment, of 4 weeks duration, compared two dietary treatments: a mixture of two of the best diets from the first experiment, and a commercial shrimp (Penaeus japonicus) feed. Lobsters were held under the same experimental conditions as in the first experiment, but were fed to excess twice daily. Their growth was significantly greater (P<0.05) on the shrimp feed (0.68 g week(-1)) than on the laboratory-pelleted diets used in the main study (0.32 g week(-1)). The results indicate that the optimal dietary protein and lipid content of the diet for P. ornatus is about 530 and 100 g kg(-1), respectively.