Effect on Growth Performance, Carcass Traits and Myostatin Gene Expression in Aseel Chicken Fed Varied Levels of Dietary Protein in Isocaloric Energy Diets

Abstract

Abstract A study was conducted to assess the effect of feeding different crude protein (CP) levels with isocaloric metabolizable energy (ME) diets on growth performance, carcass traits and myostatin (MSTN) gene expression of Aseel chicken during 0 to 16 weeks of age. A total of two hundred and ten numbers of day-old Aseel chickens were randomly allotted to seven dietary treatment groups. Each group had thirty chicks distributed into three replicates of ten chicks in each. Experimental diets were formulated to have varying levels of CP viz. 18.5, 19.0, 19.5, 20.0, 20.5, 21.0 and 21.5% with isocaloric energy of 2800 kcal ME / kg diets of mash feed were fed to birds in a completely randomised design. Different CP levels had a significant effect (P < 0.05) on body weight gain (BWG) of Aseel chicken. At the end of 16 weeks of age, the group fed 21% CP gained 223.53 g more than the lowest CP 18.5% fed group. The different CP levels did not significantly (P > 0.05) influence the feed intake of all treatment groups, but numerically highest feed intake was observed in the lowest CP (18.5%) fed group. However, significant differences in feed efficiency (FE) appeared from 13th week only with 21.0% CP fed group showing the best FE till 16th week (3.86 to 4.06). The maximum dressing % (70.61) was observed by 21% CP fed group. The CP 21% diet down-regulated the MSTN gene expression in breast muscle tissue to 0.07 folds when compared to the diet of CP 20%. The best economical coordinates for maximum performance for Aseel chicken appeared to be CP of 21% and ME of 2800 kcal/kg to achieve the best FE of 3.86 at the earliest age of 13 weeks. In conclusion, 21% CP in an isocaloric diet of 2800 kcal ME/kg, in Aseel chickens, would be optimum to improve the growth performance at maximum in terms of BWG and FE up to 16 weeks of age.