Effect of Protein Levels in Diet on Production and Emissions in WLH Layer

The present study was conducted to evaluate the effect of various levels of protein, in the diets of WLH layers, on production performance and on nitrogen (N) and phosphorus (P) levels in the excreta. The trial was conducted in a total of 108 WLH layers (BV-300) at 25 weeks of age. The birds were allocated into three dietary treatment groups; six replicates of six hens per group. Diets with 2700 Kcal/kg of metabolizable energy (ME)and a constant ratio between digestible Methionine+Cystine (M+C), Threonine (Thr), Tryptophan (Try), Arginine (Arg), Isoleucine (Ile) and Valine (Val) to digestible Lysine (Lys) (86, 66,19, 114, 72, 80 respectively) were prepared based on corn-soy and were fed to birds from 25 to 44 weeks of age. During the final stage of feeding trial, metabolic trial was held in 3 consequent days to record the N and P levels in the excreta of WLH layers. Results demonstrated that egg production, egg weight and feed conversion ratio (FCR) (g/g) were not influenced by the level of protein in diet. Body weight was increased with the increase of protein levels in diet. Gain over feed cost compared to control (17% CP) was recorded as $1 and $ 0.67 in low (13.38%) and medium (15.58%) protein groups, respectively. The percentage of N was increased and percentage of phosphorus was decreased significantly (P<0.05) in the excreta with increasing the level of protein in diet. Taken together, decreasing the level of protein in diet of WLH layers with supplementation of essential amino acids improves the production and also reduces the nitrogen excretion into the faeces in turn emissions from poultry to environment can be minimized.