Effects of early feeding technologies providing methionine supplementation on performance, lipid oxidation, and some immune-related gene expression in broiler chicken

In ovo administration of DL-methionine and post-hatch Hydrogel® supplements were tested to examine the impact of early feeding on performance and immune-related traits in a commercial broiler stock. One thousand one hundred and twenty Ross 308 eggs were incubated and assigned to seven treatment groups: intact (no in ovo administration) and immediate feed access (C1), in ovo saline treatment and immediate feed access (C2), intact and delayed feeding (ID), in ovo saline treatment and delayed feeding (IoS), in ovo DL-Methionine treatment and delayed feeding (IoM), intact and delayed access to feed, but immediate access to commercial Hydrogel® without (Hyd) or with 5mg/kg (HydM) DL-methionine post-hatch. The results showed, that the in-ovo methionine may have positive effects on the weight gain of the birds (p < 0.001) compared to the commercial Hydrogel® however, it cannot compete with the immediate feeding. The number of heterophils decreased significantly (p < 0.001) by day 21 in ID and IoS compared to the immediately fed control (C1). The number of lymphocytes, monocytes, and eosinophils, increased in treatments supplemented with methionine (p < 0.05) (IoM,HydM) indicating enhanced immune protection. There were no differences in the total antioxidant capacity (FRAP) and malonaldehyde concentration (MDA) (p = 0.07) in the examined groups. The Cytochrome P450 H1 (CYP2H1) gene was downregulated in all treatment groups (on days 21 and 35) indicating a slower metabolism, particularly in the ID group compared to C1 and C2 (p < 0.001). The HydM treatment could upregulate the IL2 expression as the immediate feeding, while only IoM treatment resulted in significant downregulation by day 35 (p < 0.001). IL6 was upregulated in all treatment groups (p < 0.001) except for HydM, where the gene expression did not differ from the housekeeping gene. Early administration of dietary methionine has a positive effect on performance and the immune system, however, none of the early feeding methods can compete with immediate feed access. The possible positive effects of early nutrition and its epigenetic impact should be examined in further studies.