Marginal deficiencies of dietary arginine and methionine could suppress growth performance and immunological responses in broiler chickens
Methionine (Met) is another essential amino acid, usually considered as the first limiting amino acid in corn‐soybean meal‐based diets (Leeson & Summers, 2005; Rafeeq, Naseer Pasha, Tariq, & Bajwal, 2011). This has been well documented that Met (Rama Rao, Praharaj, Reddy, & Panda, 2003; Shini, Li, & Bryden, 2005) and Arg (Lee, Austic, Naqi, Golemboski, & Dietert, 2002; Tayade, Jaiswal, Mishra, & Koti, 2006) have important roles in immunological functions and serve immunoregulatory actions. A strong interrelationship between Arg and Met was reported in broiler chicks (Chamruspollert, Pesti, & Bakalli, 2002; Khalifeh‐Gholi & Jahanian, 2012). Keshavarz and Fuller (1971) suggested that at least one of the main mechanisms involved in the relationship between Arg and Met is the formation of creatine. Almquist, Mecchi, and Kratzer (1941) in their study proved this fact that Arg and glycine are the biological precursors for creatine biosynthesis in the avian species. Glycocyamine is produced by the combination of Arg and glycine. Thereafter, a methyl group of Met is utilized to complete the formation of creatine. The interrelationship of these three amino acids for creatine biosynthesis was confirmed by Fisher, Salander, and Taylor (1956). In addition, one of the common biochemical mechanisms of these critical amino acids is their involvement in the biosynthesis of polyamines (Calder et al., 2002).
Khalifeh‐Gholi and Jahanian (2012) in their study with broiler chickens showed that there is a close relationship between Arg and Met in promotion of immunological responses in broiler chickens. Because Arg and Met are critical amino acids in poultry nutrition and there are few research studies concerning their interaction in deficient‐diets, the present study was designed to investigate the interactive effects of dietary Arg and Met on performance, immunological responses, blood metabolites, and carcass characteristics of broiler chickens.