Nutritional Strategies to Maintain Efficiency and Production of Chickens under High Environmental Temperature

Climate model projections indicate that the global surface temperature will probably rise a further 1.1 to 6.4°C during the twenty-first century, which is expected to have a significant impact on the efficiency, production, morbidity and mortality of domestic animals. Presently, high environmental temperature exposure is of major concern for the poultry industry especially in hot regions of the world because of the resulting poor performance, immuno-suppression and high mortality. There are different nutritional strategies for decreasing heat production to alleviate stress in high temperature-exposed chickens. The nutritional strategies are designed after considering factors such as the type of birds, age of birds, stage of production, duration of heat exposure, intensity of heat exposure and health of the birds. The nutritionists can base their strategy on less heat-production, increased nutrient intake, decreased energy wastage, and reduction in heat-induced oxidative stress and damage in birds to overcome the deleterious effects of high temperature on metabolism, physiology, feed efficiency, production performance and health. This can be accomplished by nutritional strategies to reduce heat stress by feeding good quality feed with high digestibility and nutrient density, adding fat as an energy source, balancing and provision of additional amino acids, and supplementing with vitamins, minerals and glucose. Recently, new concepts have been proposed for nutritional strategies that focus on the reactive oxygen species (ROS) production by the birds and decrease the oxidative stress and damage caused by exposure to high environmental temperature. None of these strategies are effective alone in terms of growth, feed efficiency, livability, product quality, stress tolerance or immune response, however, a combination of the nutritional strategies may help to alleviate the deleterious effects of heat stress and maintain the efficiency and production of chickens under high environmental temperature.