Effect of methionine levels on production performance, triglyceride and non-esterified fatty acid in laying hens

This study was conducted to evaluate the effect of methionine (Met) on egg production, liver triglyceride and blood free fatty acid (non-esterified fatty acid; NEFA) in laying hens aged 21 to 32 weeks old by using completely randomized design. Low-protein diet (14% CP) containing Met at 0.28 (unsupplemented group), 0.30, 0.38 or 0.44% of diet were used. The results showed that egg production and egg mass tended to increase, while feed and energy efficiency were significantly improved when Met levels increased (p<0.05).Liver weight and liver triglyceride were significantly increased by the Met supplementation, but there was no evidence of fatty liver syndrome. In addition, NEFA was slightly decreased but body weight tended to increase due to adding Met, although statistical differences were not seen. In conclusion, the improvement of egg production caused by an increase of Met levels may be closely related with the changing proportion of lipogenesis and lipolysis due to an improving amino acid balance.