Differential expression of growth and immunity related genes influenced by in ovo supplementation of amino acids in broiler chickens

The present study was aimed at investigating the role of in ovo administered amino acids: lysine, arginine, threonine or methionine plus cysteine (Met+Cys) in 14-day embryos on expression profile of growth (chicken growth hormone (cGH), insulin like growth factors (IGF) I and II, and mucin) and immunity related genes (IL-2, IL-4, IL-6, IL-12, TNF-α, and IFN-γ). On incubation day (ID) 18, higher (P < 0.01) cGH and mucin gene expression was observed in lysine, threonine, arginine or Met+Cys injected embryos, while IGF-II expression was higher in threonine, arginine or Met+Cys injected embryos on ID 20. Expression of growth genes was down regulated (P < 0.01) on day of hatch in most of the amino acids injected chicks. On day 7 post-hatch (PH), threonine or arginine exhibited higher expression of cGH, IGF-I, and IGF-II but higher mucin gene expression only on day 14 PH. Threonine or Met+Cys injected birds had higher expression of IL-6 and TNF-α, while arginine injected birds had higher TNF-α expression. Lysine, threonine or Met+Cys injected birds had higher IL-2, but lower of IL-12 and IFN-γ gene expression. It is concluded that arginine and threonine enhanced the expression of growth related genes, while threonine and Met+Cys modulated expression of immune genes in broiler chickens.