The Expression of Heat Shock Protein 70 and Glutathione Peroxidase Gene with Selenium Supplementation and Its Effect on Productivity of Broiler in Tropical Environment.

Abstract

Indonesia is a tropical country with an average temperature of 23 °C - 33 °C and humidity of 45-97% (BMKG 2012). The temperature and humidity have an impact on performance of broiler chickens. Heat stress is triggered by changes in ambient temperature. Heat stress can affect the productivity of broiler chickens. The newest strains of broiler chickens are the result of intensive selection with rapid growth ability which must be maintained at comfortable temperature. New possibilites for improving the performance of broiler production through the application of nutrigenomics approach to optimize the use of broiler chickens nutrients. Generally, nutrigenomic covers the nutrient development with affects expression of genes thus nutrigenomics of broiler should focusing on optimizing feed for broiler productivity. Selenium is an trace mineral which has antioxidant effect. Supplementation of organic selenium in broiler ration related with its antioxidant activity could reduce the effect of heat stress. The purpose of this experiment was to study the supplementation of selenium on expression of heat shock protein 70 (HSP70) and glutathione peroxidase (GPX) gene, glutathione peroxidase (GSH- Px) enzyme activity, malondialdehyde (MDA) and productivity (feed intake, body weight, body weight gain, feed conversion ratio and mortality) of broiler in tropical environment. The experiment was conducted using completely randomized designs with three treatments and four replications. The treatments in this experiment were: comfortable environment pens (25.0 oC-27.9 oC) using air conditioner without supplementation of selenium (AC), tropical environment pens (24.6 oC-32.9 oC) without supplementation of selenium (NS), and tropical environment pens (24.6 oC-32.9 oC) with supplementation of 0.30 ppm selenium (organic selenium (Optimin®SeY, Nutreco)) (PS). Each of treatment consisted of 40 day old chicks (DOC) strain Cobb (unsex). Parameters observed were HSP70 and GPX gene expression, GSH-Px enzyme activity, MDA and the productivities. The results showed that supplementation of organic selenium significantly increased (P<0.05) feed intake, body weight, body weight gain, and feed conversion ratio. By contrast, the expression of HSP70 and GPX gene, GSH-Px enzyme activity and MDA of broiler significantly decreased (P<0.05) in the tropical pens with organic selenium supplementation compared to the treatment without organic selenium supplementation. It is concluded that supplementation of 0.30 ppm organic selenium in broiler ration in tropical environment improved modulating the expression of HSP70 and GPX gene, and showed similar performance to broiler which kept in the comfortable environment without organic selenium supplementation by reduces oxidative stress in broiler which kept in tropical environment.