Dietary Methionine and Broiler Chicken Growth: Evaluating Performance and the GH/IGF-I Axis

Methionine is an essential amino acid crucial for various physiological functions in broiler chickens, including growth, metabolism, and immune response. Understanding the optimal levels of methionine supplementation is vital for maximizing poultry production efficiency and bird health. This study aimed to evaluate the effects of dietary methionine supplementation on growth performance and gene expression in broiler chickens. The study was conducted at the College of Veterinary Medicine, Al-Qadisiyah University, from 26 September 2024 to 6 November 2024. The study utilized broiler chickens divided into experimental groups based on varying levels of dietary methionine supplementation. Broiler chickens were assigned to different dietary treatment groups with varying levels of methionine supplementation. Growth performance and gene expression were assessed at regular intervals throughout the study period. Statistical analyses were performed to determine significant differences between treatment groups. The results show in the dietary methionine supplementation improved body weight gain and feed conversion ratio. Optimal feed conversion ratios were observed in the T3 group, with mean FCR over the 6-week study ranging from 2.01 ± 0.42 (C) to 1.55 ± 0.17 (T3). It also significantly increased GH and IGF-1 concentrations (LSD = 1.81 and 2.059, respectively). Dietary methionine supplementation at varying levels influences growth performance and gene expression in broiler chickens, demonstrating its significant role in broiler physiology.