During summer, under high ambient temperature conditions, the thermoregulatory system of the body adjusts a variety of physiological mechanisms through a combination of heat exchange and evaporative heat loss to attain a balance between the heat produced within the body and the heat lost to the environment. In chickens sweat glands are absent making it more vulnerable for dissipation of heat and reducing stress. Leptin affects energy homeostasis by decreasing food intake and by up-regulating fatty acid oxidation. In chicken leptin and ghrelin are known as anorexigenic hormones. Effects of yeast products on production and their mode of action in monogastrics have been reported in poultry. It is reported that yeast products affect nutrient digestibility, growth and immune system. Fermented yeast culture contains viable cells, cell wall components, metabolites, and the media on which the yeast cells were grown. No study has been carried out on endocrinological and histopathological studies with supplementation of fermented yeast culture in chicken and their relation with egg production, especially during summer season. This study was carried out to determine pattern of leptin and ghrelin secretion among other oxidative markers in PD 3 chicken line (Dahlem Red) with histopathological conditions in the intestine, when subjected to natural heat stress during summer season. During summer the temperature ranged between 26ºC and 36.9ºC and post summer season it ranged between 29ºC and 32ºC. A hundred number of 16 week old Dahlem Red (PD-3) breed of chickens whose body weight ranged between 850-950g were selected and randomly allotted to two groups of fifty birds each. The experiment was continued from 16-32 weeks of age. After eight weeks (April-May) of summer season, experiment was continued till the birds attained 32 weeks of age. The two groups were Control and Treatment groups. The treatment group received 1.25g of fermented yeast culture (Saccharomyces cerevisiae) commercial product per kg feed. Blood samples were collected at weekly intervals, plasma was separated and analyzed for Leptin, Ghrelin hormones, plasma protein carbonyls, MDA, cholesterol and free fatty acids. Fortnightly body weight and feed intake of the birds were recorded. Egg production and egg weight were also recorded. Based on these observations, feed conversion ratio (FCR) was also calculated. Supplementation of fermented yeast culture decreased the concentration of plasma Leptin and Ghrelin (P<0.01), Cholesterol (P<0.01) and MDA (P<0.01) during summer season and feed intake of birds during post summer season. It was observed that the egg production increased from 26-31 weeks of age and FCR was significantly less (P<0.05) in the supplemented group. It was observed that fertility and hatchability of eggs was more for the supplemented group. In conclusion providing fermented yeast culture to the sexually maturing hens during peri and post summer period improved feed efficiency, egg production with no improvement in the morphology of the jejunum. However the severity of necrosis decreased from medium to mild stage in both the groups from pre to post laying period.

Download this article as