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 mea l in isonitrogenous practical diets for the juvenile black tiger shrimp Pen aeus monodon was evaluated through the studies of growth, digestibility and pellet water stability. Five isonitrogenous diets were formulated to conta in 40% protein. Protein from dehulled Lupinus albus seed meal replaced 0, 2 5, 50, 75 and 100% of the protein from defatted soybean in the diets. Juven ile P. monodon (4.35 +/- 0.31 g) were assigned randomly and fed each test d iet at a daily feeding rate of 5% body weight for 42 d in triplicate tanks equipped with a Row-through sea water system. No statistically significant differences were observed in weight gain, feed intake, feed conversion rati o (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 appa rent 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 differ ence in whole body composition (dry matter, lipid, protein and ash) of shri mp on the various diets. The poorest pellet water stability was displayed b y the diet with 100% replacement while the diet containing a combination of soybean meal and lupin meal (50% replacement) was the most stable. The res ults have demonstrated that dehulled lupin seed L. albus meal has good pote ntial as a substitute protein source for up to 50% of the protein from defa tted soybean meal and could be included up to 17% inclusion level in juveni le P. monodon practical diets with no adverse effects on growth, feed intak e, FCR, survival, feed utilization, body composition, and digestibility coe fficients of dry matter and protein.