Molecular Mechanisms Associated with Dietary Methionine Deficiency in Meat-Type Chickens

Methionine is the first limiting amino acid in a typical poultry diet. Restriction of dietary sulfur amino acids (SAA) to growing chickens leads to reduced growth and oxidative stress. The molecular mechanisms that underlie such restrictions remain scant. We studied the molecular mechanisms that underlie SAA restrictions in broiler chickens from 3-5 weeks of age in the Pectoralis major major muscle using next generation sequencing. Fold change of ≥1.5 and false discovery rate of ≤0.05 were used as criteria for differentially expressed genes (DEGs). There were 554 downregulated DEGs and 365 unregulated DEGs in the deficient group compared to the controls. Signaling pathway impact analysis showed that the Fc gamma R-mediated phagocytosis, NK cell mediated cytotoxicity and NF-kappa B signaling pathways were activated whereas the B cell receptor signaling pathway was inhibited in the Pectoralis major of the SAA restricted birds. The current study suggests that restriction in dietary methionine in growing chickens leads to cytoskeleton modification that reduces cell to cell communication, potential increase in oxidative stress and abnormal methylation which induces inflammation response. Birds eliciting such inflammation response may compromise their immune system and their ability to fight infections.