Comparison of the effect of in ovo injection of L and DL methionine on embryonic growth, hatchability percentage and performance of broiler chickens

Methionine is the first limiting amino acid in the poultry diet, and it plays essential roles in energy production and protein synthesis, increasing the growth performance of broiler chickens. This trial was conducted to compare the effect of L- and DL-Methionine on hatchability, productive performance and biochemistry of some blood parameters of broiler chicken from 1 to 7 day of age. On days 16 of incubation, 800 fertile egg (Ross 308) were randomly divided between 8 treatments (and 4 replicates) including 3 levels of L-Methionine (10, 20 and 30 mg), 3 levels of DL-Methionine (10, 20 and 30 mg) and two control treatments including negative (no injection) and positive (injection of 200 microliters of saline) control. Results showed that all treatments significantly (p<0.05) decreased the hatchability, without no effect on chick weight, chick to egg weight ratio and feed intake from 1 to 7 days of age. Birds received 30 mg L-Methionine showed the best BWG (27.3 g) and FCR (0.62). Likewise, 30 mg L-Methionine increased the carcass to live weight ratio (50.5) significantly (p<0.04). The applied treatments compare to the negative control group significantly (P<0.04) decreased triglyceride content of serum in the chickens. In general, the results of this research showed that injection of 30 mg of L-methionine compared to DL-methionine can lead to increased performance and improved carcass ratio in 7 days.