Influence of dietary protein level with or without fish meal on the performance of crossbred male pigs

In a 3x2 factorial design, 30 crossbred (LWY x Indigenous) male pigs (35.64±0.26 kg) were divided into 6 equal groups and fed ad lib upto 70 kg live weight on rations formulated to contain either fish meal or synthetic L-lysine and DL-methionine with 16 (R₁, R₂), 14 (R₃, R₄) and 12% (R₅, R₆) CP. The digestibility of nutrients was comparable except EE digestibility, which was higher (P<0.01) in high CP (16%) diets and due to amino acid supplementation (P<0.05). Higher N intake (P<0.05), total N excretion (P<0.01) and N retention (P<0.01) was observed with increase in the CP content but the N retained as percent of intake or absorbed was comparable among the treatments. The ADG, feed/kg gain and cost of feed/kg gain were comparable among treatments. Higher (P<0.05) ADG and superior FCR was observed due to amino acids supplementation. The results suggest that for finishing pigs a diet with 16% CP along with synthetic amino acids can be economical without affecting their performance and beneficial in reducing environmental pollution through reduced N excretion.