EFFECTS OF DIETARY PROTEIN LEVELS AND SUPPLEMENTAL LYSINE ON PERFORMANCE OF LAYING HENS

An experiment was conducted to assess the effects of supplemental L-Lysine HC1 at two dietary protein levels (13 and 14%), which contained lysine at 80% (0.56% lysine) of NRC recommendations. To these diets lysine was added in such a way that other experimental diets at each protein level contained lvsine at the rate of 90, 100, 110 and 115% (0.62, 0.69, 0.76 and 0.79% lysine) of NRC recommendations. Two hundred and fourty Hy-line W-36 layers (52 wk of age) were divided into 60 groups (replications), four hen per replicate. Each experimental diet was given to six replicates for a period of 16 wk. Egg production (EP), egg weight (EW), egg output (EO) and feed consumption (FC) were not significantly affected by dietary protein. Feed conversion ratio (FCR) was significantly (P<0.05) improved due to increasing dietary protein. Lysine significantly affected EP, EW (P<0.05) and FCR (P<0.001). FCR was increased due to lysine supplementation. Hens consuming about 520 mg d^-1 lysine at both protein levels had better EP, EW, EO and FCR.