Effect of Withdrawal of Lysine and/or Methionine from the Diet on Performance of Brown Egg-Type Layers

This study was undertaken to evaluate the effects of withdrawal of lysine and/or methionine on productive performance and egg quality of black Bovan Nera layers at their 20^th weeks of laying. The experiment was conducted on 96 brown egg-type layers divided into 4 groups with 3 replicates, each replicate having 8 birds using complete randomized design. Birds were fed isoenergetic and isonitrogenous diets for seven weeks as per requirements. The diet in group G₁ contained both lysine and methionine while diets were devoided of supplementary lysine, methionine and lysine + methionine in groups G₂, G₃ and G₄, respectively. The daily feed intake was similar in all the groups irrespective of addition or deletion of lysine and/or methionine. Hen day egg production was higher (P<0.05) in group G₁ compared to other groups. Feed conversion ratio (kg feed consumed/per dozen egg) was better (P<0.05) in groups G₁, G₂, G₃ compared to group G₄. Net feed efficiency index was higher (P<0.05) in group G₁ compared to other groups. The values of egg weights and egg mass were comparable among groups G₁, G₂ and G₃ but higher (P<0.05) than those in group G₄. The values of yolk weight, shell weight and Haugh units were higher (P<0.05) in group G₁ compared to groups G₂ and G₃ and the least (P<0.05) values were recorded in group G₄. The shell thickness in group G₁ was higher (P<0.05) than other treatments. It was concluded that withdrawal of lysine and/or methionine from the diet of layers reduced (P<0.05) egg weight, yolk weight, shell weight and Haugh units. FCR was better in groups supplemented with methionine, lysine or both compared to the group that lacked both the amino acids.