Effect of supplemental dl-methionine on performance of commercial laying hens during summer

An experiment was conducted to evaluate the performance of commercial White Leghorn (WLH) layers fed diet supplemented with DL- methionine (Met) during summer (29–43°C). WLH layers 26 wks of age with an average of 78 per cent hen day egg production (HDEP) were equally distributed into 3 groups of 24 each and were housed in individual California type cages in open side housing system. A basal diet based on maize-soybean-sunflower-deoiled rice bran without supplemental methionine (Met) was formulated (0.3% Methionine). Test diets were prepared by supplementing DL-Met at 0.0, 0.06 and 0.12 per cent to arrive 0.30, 0.36 and 0.42 per cent Met in the diet. The HDEP and feed efficiencyincreased significantly by supplementation of 0.06 per cent Met to the basal diet containing 0.30 per cent Met. However, no further improvement in egg production could be noticed by enhancing the Met supplementation to 0.12 per cent. Neither egg weight nor daily feed consumption was influenced by Met supplementation. The egg quality parameters such as specific gravity, shell-breaking strength, shell weight and shell thickness were not influenced due to supplemental Met in the diet. However, Haugh unit improved significantly due to 0.06 per cent Met supplementation. The serum protein, albumin and globulin concentrations were significantly higher in Met supplemented groups compared to that of control. The serum ALP activity lowered significantly due to 0.06 per cent Met supplementation and increasing the level to 0.12 per cent did not prove to be advantageous. The antibody production in response to sheet RBC inoculation improved significantly by supplementation of 0.06 per cent Met to the basal diet. No further advantage in antibody production could be noticed by enhancing the Met supplementation from 0.06 to 0.12 per cent. Similarly, the persistency of antibody production was higher in birds fed supplemental Met as compared to control group. It may be concluded that supplementation of 0.06 per cent DL-Met to the basal diet containing 0.3 per cent Met (375 mg Met/hen/day) is essential to support egg production, albumen quality and immune response in commercial WLH layers during summer (29–43°C).