Replacement of soybean meal by lupin meal in practical diets for juvenile Penaeus monodon

. The potential of lupin meal as an alternative protein source to soybean meal in isonitrogenous practical diets for the juvenile black tiger shrimp Penaeus monodon was evaluated through the studies of growth, digestibility and pellet water stability. Five isonitrogenous diets were formulated to contain 40% protein. Protein from dehulled Lupinus albus seed meal replaced 0, 25, 50, 75 and 100% of the protein from defatted soybean in the diets. Juvenile P. monodon (4.35 × 0.31 g) were assigned randomly and fed each test diet at a daily feeding rate of 5 % body weight for 42 d in triplicate tanks equipped with a flow‐through sea water system. No statistically significant differences were observed in weight gain, feed intake, feed conversion ratio (FCR), protein conversion efficiency and apparent protein utilization of shrimp fed diets with 0, 25, and 50% replacement. Shrimp fed the diet with total replacement of soybean meal by lupin meal had the poorest performance (P < 0.05) with regard to the above parameters. Survival was similar (87%) for all dietary treatments. The apparent dry matter digestibility and apparent protein digestibility were similar for all diets ranging between 70.5 and 72.8% and 89.7 and 90.8%, respectively. There was no significant difference in whole body composition (dry matter, lipid, protein and ash) of shrimp on the various diets. The poorest pellet water stability was displayed by the diet with 100% replacement while the diet containing a combination of soybean meal and lupin meal (50% replacement) was the most stable. The results have demonstrated that dehulled lupin seed L. albus meal has good potential as a substitute protein source for up to 50% of the protein from defatted soybean meal and could be included up to 17% inclusion level in juvenile P. monodon practical diets with no adverse effects on growth, feed intake, FCR, survival, feed utilization, body composition, and digestibility coefficients of dry matter and protein.