Effect of reduced dietary crude protein and supplemental limiting amino acids on the growth and carcass characteristics of Swarnadhara chicks

Abstract

A six-week trial was conducted to determine the effect of lowering dietary crude protein levels with supplementation of limiting amino acid on growth performance, and carcass characteristics in one of the Indian improved crossbred Swarnadhara chicks in a completely randomized design having five treatments and four replications of 20 birds in each. Five isocaloric (2800 ME Kcal//kg) experimental diets based on corn-soy bean meal were formulated in a gradual crude protein decline from 21 % (control T1) to 19% by 0.5% interval. The levels of limiting amino acids namely methionine, lysine, threonine and tryptophan were met as that of control (T1) by adding synthetic preparations. Highest body weight was recorded in 2% crude protein reduced group (T5) which was comparable with control (T1). However, cumulative feed intake and feed conversion ratio of different treatments were not significantly different. Moreover, carcass parameters like dressing percentage, breast meat yield, liver and heart weights remained unaffected by the dietary treatments. Relative gizzard weight and abdominal fat weights showed variations and lower dietary protein diets were comparable with control diet (T1). In summary, crude protein content of Swarnadhara chick diet can be reduced to 19% with essential AA fortification without any adverse effect on growth performance and carcass characteristics during 0-6 weeks of age.