ABSTRACT This experiment was conducted to examine the effects of dietary L-arginine (Arg) supplementation on growth performance, intestinal morphology, serum biochemical and hematological parameters in meat-type quails. A total of one hundred and sixty 7-d-old male quail chicks were weighed and allocated to four treatment groups of four replicates, with 10 chicks/replicate. Four groups of quail chicks were fed basal diet containing 12.44 g lysine (Lys)/kg of diet (control), basal diet supplemented with 0.4, 1.21 and 1.84 g Arg/kg of diet (for Arg to Lys ratios of 100, 103, 109 and 114) for 28 days. The birds were fed diets from 7 to 38 d of age. Final body weight and feed:gain tended to improve by increasing Arg:Lys ratio to 109. Relative weight of spleen and bursa were significantly (p<0.05) increased by the addition of 0.4 g Arg/kg of diet. Morphometric parameters of jejunum were not affected by the dietary treatments. The uric acid, and triglyceride concentration of the serum significantly (p<0.05) decreased by increasing the Arg:Lys ratio to 114. Serum HDL-cholesterol concentration were significantly (p<0.05) increased by increasing the Arg:Lys ratio to 114. Monocytes were decreased by increasing the Arg:Lys ratio to 114. In conclusion, our results indicated that Arg supplementation in the quail diets did not appear to have any significant positive effects on performance criteria and although increasing Arg:Lys ratio to 114 could improve serum biochemical parameters.

The study was conducted to evaluate carcass yield and chemical composition of thigh and breast muscles of broilers fed three different lysine requirement levels: high lysine (+10% NRC), standard (NRC) and low lysine (-10% NRC) and two ways of expressing amino acids in feedstuffs (total or digestible amino acids). The results of this study showed that diet formulation based on digestible amino acids significantly influenced breast yield and abdominal fat deposition. The study showed that increasing lysine level (+10% NRC) of diet significantly increased both carcass and breast percentage and also carcass, breast and thigh weight. The interaction between digestible amino acids and lysine requirement levels affected carcass and breast percentage. Feeding broilers high lysine diets (+10% NRC) significantly increased lysine content in breast and thigh. The response to formulation based on digestible amino acids was maximized when broilers received the high lysine level diet.