بررسي عملكرد رشد و تركيب لاشه جوجه هاي گوشتي سويه تجاري راس در پاسخ به نوع الگوي پروتئيني جيره

The study of growth performance and carcass yield of Ross broiler chicks in response to different dietary protein profiles

The aim of this study was investigating the growth performance, carcass yield and litter quality of Ross 308 broiler chicks when feeding was based on common protein profiles in dietary formulation of broiler chicks. Four protein profiles consisted of NRC (1994) recommendation, 90% protein recommendation by NRC (1994) (low protein diet), Ross strain nutrition guide and phase feeding approach was fed to broiler chicks for 42 day. All dietary treatments had 3000Kcal/Kg ME and the feeding time for each protein profile was based on its recommendation. All diets had similar quantity of nutrients, except of protein and amino acid quantity. Five replicate groups of 40 birds were allocated to each treatment. Results of experiment showed that birds were fed by NRC (1994) recommendation and Ross nutrition guide had higher body weight gain than those were fed by low protein diet or phase feeding approach (1992 and 1915gr vs 1785 and 1764gr, respectively) (P<0.05). Low protein diet and phase feeding approach resulted to significant decreased of feed intake, protein intake and energy (P<0.05). Highest protein efficiency ratio and energy efficiency ratio was related to birds were fed by low protein diet (2.78) and NRC, 1994 recommendation, respectively. Birds were fed by NRC (1994) recommendation or Ross nutrition guide had better carcass yield, however reducing dietary protein level resulted to significant decrease of litter nitrogen percent (P<0.05).