Effect of Supplementation of Fermented Yeast Culture During Summer on Plasma Leptin and Ghrelin and Expression of their Receptors in Different Tissues and on Production Performance During-Post Summer Period in PD 3 Chicken Line

The present experiment was conducted to observe the effects of supplementation of fermented yeast (Saccharomyces cerevisiae) culture (FYC, a commercial product at 1.5×10⁷ cfu/g) on physiological blood parameters, expression of genes for hormone receptors and on production performance of layers during summer season. The control group was devoid of supplementation of FYC. A total of 150 layers (PD 3 chicken line; 17 weeks age) were divided into three equal groups each comprising of 10 replicates of 5 birds. The dietary treatments included supplementation of FYC to the basal diet at 0 (C; control), 0.5 (T1) and 1.25 (T2) g/kg. The results indicated that the concentration of the hormones leptin and ghrelin was significantly (P<0.01) greater for the control group. Further, the plasma concentration of malondialdehyde (MDA) (P<0.01) and total cholesterol (P<0.05) were significantly greater at 49d of the experiment in the control group when compared with the respective parameters in the group of birds supplemented with the higher dose (1.25 g/kg) of yeast culture (T2). The expression of leptin-and ghrelin-receptors was downregulated in the treatment groups significantly (P<0.05) in brain, liver (T2) and magnum (portion of reproductive tract) tissues (T1). The histopathological evaluation of the intestinal tissues indicated that the severity of the necrosis of the villi of the jejunum was mild for the treatment groups when compared with that of the control (C) group. Hence, it can be concluded that supplementation of yeast culture @ 1.25 g/kg was beneficial in lowering stress markers like cholesterol, MDA and further reducing the severity of necrosis resulting in increased egg production, fertility and hatchability.