Effect of different protein levels with ideal amino acid ratios to digestible lysine on performance of 61-72 weeks White Leghorn layers

The present experiment was conducted to investigate the minimum protein requirements of white leghorn layers on diets with ideal amino acid ratios to digestable lysine from 61 to 72 weeks of age. The trial was performed with four treatments and twelve replicates with twelve birds per replicate. All the diets were based on maize, de oiled rice bran, soybean meal and ground nut cake. At 2600 kcal ME level, the digestible lysine requirement was fixed at 0.69% i.e. an intake of 620 mg dig Lysine (total lysine intake 690 mg/ b/d). The protein in the control diet was 16.25% (T1). In the other 3 experimental diets, crude protein (CP) content was reduced to 15.69 (T2), 15.13 (T3) and 14.58% (T4). The results revealed that significantly (P<0.05) higher egg production and egg weight were recorded in control (16.25%) and low protein diet (15.13%) compared to other treatments. Feed intake, Haugh unit, albumin index and egg density were not influenced by different dietary groups. But yolk index was significantly (P<0.05) higher in low protein groups compared to control. Supplementation of all low protein diets obtained higher returns over feed cost than the control. Therefore, a 15.13% CP diet with 0.69% digestible lysine is adequate for 61-72 weeks white leghorn layers.