Effect of Varied Dietary Concentration of Protein and Critical Amino Acids on Multicolored Broiler Chickens

A study was conducted to determine the effects of reduced dietary levels (−10% to -20%) of protein and critical amino acids on multicolored broiler chicks, Krishibro. A total of 360 day-old coloured broiler chicks were divided into a total of 9 groups with 8 replicates of 5 chicks each. Nine experimental diets were compounded to contain protein and critical amino acids as per NRC (1994) or reduced by 10 and 20%, either independently or jointly during starter and finisher phases and fed from 0 to 42 days of age. Body weight at 6 weeks was higher with marginally low (−10%) level of protein and TSA. Feed intake was not affected, while feed conversion efficiency at 3 weeks was better in the group fed 20% less protein with normal levels of lysine and TSA as compared to control. However, at 6 weeks of age, differences were not observed. Serum biochemical profile, immune response and slaughter variables were not affected, except abdominal fat deposition, which grossly increased with reduction in protein and critical amino acid levels in diet. Muscle fat content increased in the groups fed low protein and low methionine diets. It is concluded that marginal reduction of protein in diet by maintaining normal levels of lysine and TSA or 10% reduction in TSA was optimum for coloured broiler chicks.