Effect of dietary protein levels on growth of Penaeus stylirostris juveniles

The shrimp Penaeus stylirostris is currently produced on a commercial scale in Tahiti and New Caledonia. Both super-intensive (80 animals m−2) and semi intensive (25 m−2) systems are promoted. Locally produced commercial feed contains 380–400 g kg−1 crude protein (CP) without special consideration for environmental impact. The need for a ‘low pollution’ diet implies reconsideration of the optimum dietary protein level for this species. Under experimental conditions, six isoenergetic practical diets ranging from 270 g kg−1 to 440 g kg−1 CP were formulated and fed to satiation for 30 days to juvenile P. stylirostris; average growth rates were between 5.5 and 7.5 g per month with survival rates > 90%. The lowest protein levels 270–310 g kg−1, gave significantly (P < 0.05) poorer growth (5.5 g per 30 days) than was observed with 330–430 g kg−1 CP; 330 g kg−1 CP may be recommended, and as it is lower than levels in diets used currently, there is a possibility of reducing nitrogenous waste. In addition to growth response, protein efficiency ratio, protein productive value and food conversion (feed/gain) all supported a recommended dietary protein level of 330 g kg−1. Future prospects for practical feeds with even lower CP levels are considered.