Abstract
The need for solutions to relieve heat stress and its undesirable effects on broiler production increased, especially in hot climatic areas. The antioxidant and immune stimulant effects of herbal extracts of Emblica officinalis (Amla), Cichorium intybus (Chicory) and Allium porrum (Leek) were examined against the adverse effects of heat stress in broilers. One thousand Cobb 500 one-day-old chicks were used for this experiment. Birds were divided into four equal groups. The first served as the control group. The second received Amla extract (3 g/kg diet), the third received Chicory extract (3 g/kg diet) and the last group received Leek extracts (3 g/kg diet). All groups were daily subjected to heat stress for 12 h by increasing house temperature to 8 ± 2 °C (10:00 am to 10:00 pm daily) using an electric heater, while relative humidity was kept at 47 ± 3%. Results revealed significant improvement in final body weight in treated groups, especially the Chicory and Amla-fed groups. Total weight gain was improved by dietary supplementation with herbal extracts, while feed intake, feed conversion ratio (FCR) and mortality percentage were reduced. The positive impact of the herbal extracts was also clear on carcase traits in the treated groups. Meat and serum lipids were significantly reduced in treated groups. White blood cells, phagocytic index and antioxidant enzyme levels were positively improved by dietary supplementations. In conclusion, using Amla, Chicory and Leek extracts positively improved broilers' growth performance, immunity and oxidative stress status under heat stress conditions.
Highlights
Heat stress causes huge economic losses in livestock production worldwide.
Herbal extracts are rich in antioxidants at low prices than other feed additives.
Herbal extracts can enhance the defense system and reduce the negative effects of heat stress.