Relationship Between Plasma GH, Metabolites, Lipogenic Genes, and MMP3 Expression in PD3 Chicken Line and Role of Fermented Yeast Culture in Alleviating Heat Stress

Abstract

The present experiment aimed to observe the effect of high ambient temperature during the summer season (April–June) on growth hormone (GH), metabolites, expression of lipogenic,andmatrixmetalloproteinase (MMP3) genes in different tissues of PD3 chicken line during prelaying period and their effect on egg production in the post-summer period.We hypothesized that supplementing fermented yeast culture (FYC) to chickens during summer may alleviate heat stress by affecting GH, metabolites, and gene expression levels. Three groups of birds (PD3 line) were considered with an average bodyweight 900 g at 16wk. One group served as controlwhich did not receive any dose of supplement (FYC), and the other two groups were supplemented with FYC at the rate of 0.5 g/kg and 1.25 g/kg of feed, respectively, during and post-summer till 32 wk of age. Bloodwas collected at biweekly intervals, during summer period only. The plasma was separated and stored for estimation of hormone and metabolites. Relative gene expression study was conducted for liver and magnum portion of the reproductive tract. Our results showed that the concentration of GH was significantly (P < 0.05) higher in the control group compared to treatment groups. Expression of SCD, FAS lipogenic genes, and MMP3 genes was higher in tissues of control (P < 0.05) compared to the treatment groups during summer period. The results indicated that high ambient temperature increased the concentration of GH, cholesterol, MDA, expression of lipogenic, and MMP3 genes in different tissues of chickens during summer (pre-laying) period and supplementation of FYC decreased the level of hormones, metabolites, and gene expression. Therefore, the supplement reduced the effect of heat stress and increased egg production during laying period coinciding with post summer period.