Optimizing Limiting Amino Acids Profile of Broiler Chickens at High Altitude of Kumaun Region

An experiment was conducted during rainy season at high altitude of Kumaun region to optimize dietary needs of protein (limiting amino acid profile) employing 216 day-old broiler chickens (CARIBRO Dhanraja) divided into 12 groups of 18 each, reared on deep litter. Three experimental regimens with three levels of limiting amino acids (LAA; 115, 100 and 85% of NRC) were formulated at fixed energy level of 3000 kcal ME/kg. The protein levels were 21.9 and 20.2% (LAA₁₁₅), 19.2 and 17.6% (LAA₁₀₀) and 16.2 and 14.9 (LAA₈₅) during starting and finishing phases, respectively. Each diet was fed to 4 replicated groups. During different phases of growth, the gain in BW, feed intake and FCR improved (P<0.01) in diets having LAA at 115 and 100% NRC levels than control diet. The birds fed LAA₁₀₀ or LAA₁₁₅ had similar BW gain, feed intake and FCR. Lower (P<0.01) BW gain and poorer feed conversion was observed in LAA₈₅. The alkaline phosphatase, triglyceride, corticosteron and thyroxine did not differ except plasma calcium and triiodothyronine, which were higher (P<0.01) at high LAA₁₁₅. The edible meat yield and eviscerated yields were significantly (P<0.01) lower in LAA₁₁₀ group than LAA₁₁₅ group. Therefore, the results indicated that a diet with limiting amino acid profile as suggested by NRC (1994) with 19.2 and 17.6% for starting and finishing period and 3000 kcal ME/kg for overall phase was suitable for broilers on high altitude of about 8000 ft.