Perspective Chapter: Using Feed Additives to Eliminate Harmful Effects of Heat Stress in Broiler Nutrition

Abstract

Global warming is one of the major challenges for mankind, with animal breeding one of the most affected sectors in the agricultural industry. High ambient temperatures negatively affect all domestic animals. While it is true that pork and dairy production suffer the consequences of heat waves, it is actually the poultry industry which is hit the hardest by the heat stress poultry must endure due to hotter weather. Consequently, we have a fundamental interest in reducing and/or eliminating the negative effects of climate change, i.e. prolonged high ambient temperatures. The aim of this chapter is to present the adverse effects of heat stress on energy metabolism, anti- and pro-oxidant capacity and production in birds. A further goal is to show how various feed additives (e.g. vitamin A, C and E, selenium, zinc, betaine, plant extract, and probiotics) can reduce the negative effects of heat stress. Based on the large number of recent scientific findings, the following conclusions were drawn: Using fat in the diet (up to 5%) can reduce heat production in livestock. Vitamins (e.g. A, E and C) are capable of reacting with free radicals. Vitamin E and Vitamin C, Zn, and Se supplementation improved antioxidant parameters. Antioxidant potential of vitamins and micro minerals is more efficient in combination under heat stress in poultry nutrition. Plant extracts (e.g. oregano) could decrease the negative effects of heat stress on antioxidant enzyme activity due to its antioxidant constituents. Betaine reduces heat production in animals at high ambient temperatures. While acute heat stress induces a drop in feed intake, with the resulting increased nutrient demand leading to weight loss, if heat stress is prolonged, adaptation will occur. Probiotics and vitamins (C and E) seem to be the most effective means to reduce the negative effects of heat stress.