Broiler chickens are remarkably efficient animals, but their performance comes at a cost: sensitivity to heat stress. As environmental temperatures rise above 28 degrees C, broilers begin to reduce feed intake, lose weight gain efficiency, and show elevated mortality rates. Once temperatures exceed 32 degrees C, even short-term exposure can trigger metabolic collapse in fast-growing flocks. So, how can nutrition help mitigate these risks?
Understand heat-stress physiology
Heat-stressed broilers pant to cool down, which causes respiratory alkalosis, a disruption in blood pH due to loss of carbon dioxide. At the same time, feed intake drops, especially for energy and protein, leading to compromised growth and immunity.
Nutrition to the rescue with targeted strategies
- Increase energy density: Broilers in hot weather consume less, so each gram of feed must deliver more usable energy. Incorporate dietary fats, which provide concentrated energy with lower heat increment compared with carbohydrates or protein. Use highly digestible fats to minimize digestive burden.
- Reformulate amino acid profiles: Reduce crude protein slightly and use synthetic amino acids, including lysine, methionine and threonine, to maintain the correct amino acid balance. This helps sustain growth without overloading nitrogen, which increases internal heat production.
- Electrolyte balance is also critical: Add sodium bicarbonate or potassium chloride to maintain the acid-base balance disrupted by panting. Monitor and adjust the dietary electrolyte balance, with an optimal target under heat stress around 250 to 300 mEq per kilogram feed.
- Antioxidants matter more than ever: Heat stress increases oxidative damage in broilers. Supplement vitamin C, vitamin E and selenium to support the antioxidant defense system. Vitamin C is not essential in poultry under normal conditions, but it may become beneficial during heat episodes.
- Heat-stress additives can help: Certain essential oils, along with organic acids, can stimulate feed intake, support gut health and reduce inflammation. They may not be miracle cures, but they offer supportive benefits when used correctly. There are even more additives that can offer similar benefits during heat stress.
Conclusion
Managing broilers under heat stress is a race against time and biology. Nutritional strategies cannot replace good ventilation and cooling, but they can reduce the damage. By rethinking formulation and prioritizing digestibility, antioxidant support and electrolyte balance, producers can keep broilers growing even when the temperature rises.
