Effects of dietary methionine levels and L-carnitine supplementation on performance and egg quality parameters of layers

Abstract

Effects of dietary carnitine supplementation (0 and 150 mg/kg L-carnitine) on performance and egg quality parameters of layers in late laying period (from 62 to 72 weeks) fed maize-soyabean meal based diets with different methionine levels (0.26 vs 0.40%) were investigated. A RCBD with 2×2 factorial arrangement was applied. Eight replicates of the four dietary treatments (3 layers in each cage, a total of 32 cages) were randomly distributed into blocks. The study period was 10 weeks and ninety six 62-week-old Nick Chick white layers were used. In the study, dietary carnitine supplementation did not affect egg production, feed consumption and feed efficiency. However, dietary methionine below requirement level either numerically (the first 5 week from 62 to 67th weeks and overall 10-week period) or statistically (P<0.05) (last 5 week from 67 to 72th weeks) reduced egg production and feed efficiency. Similar to performance data, dietary carnitine supplementation had no impact on egg, egg yolk, and egg shell weights, however, the reduction in dietary methionine level had negative impacts on these parameters as early as 4th week of the study. Neither carnitine nor methionine improved corrected yolk and egg shell weight, yolk colour and egg shell thickness, however, both egg shape index and Haugh unit were affected by dietary methionine levels (P<0.05). In summary, carnitine supplementation did not affect layer performance and egg quality whereas dietary methionine deficiency significantly reduced layer performance and egg quality in late laying period and the effect was more visible towards the end of the study.