ARTICLE 66 FEED & ADDITIVE MAGAZINE August 2022 MITIGATE THE CLIMATE STRESS IN BROILER CHICKENS WITH PHYTOGENICS “Poultry is more susceptible to heat because of its rapid metabolic rate and high growth. The detrimental effects of heat stress can be seen on production performance, body temperature, intestinal health, appetite hormone regulation, immune responses, and antioxidative characteristics. Bioactives in phytogenic feed additives with antioxidant activity, such as polyphenols, could serve as a means to alleviate heat stress.” According to an analysis by NASA (2022), the past eight years have been the warmest since modern recordkeeping began in 1880. This remarkable escalation in global environmental temperature poses severe implications to the farming sector due to stress-associated problems such as growth depression and poor efficiency. High ambient temperature is one of the major stressors in the poultry production system, which increases production costs and severely damages the meat quality. The massive economic losses induced by extremely high temperatures during the summer are often disastrous for poultry farming. St-Pierre et al. (2003) calculated that the U.S. livestock production industry suffers a severe loss of $1.69 to $2.36 billion due to high environmental temperature, out of which the poultry industry accounts for the loss of $128 to $165 million. Poultry is more susceptible to heat because of its rapid metabolic rate and high growth. Due to the lack of sweat glands, body covered with feathers, and bred for increased productivity, birds face problems releasing heat from the body and are therefore more sensitive to heat stress. The detrimental effects of heat stress can be seen on production performance (growth reduction, meat quality loss), body temperature, intestinal health, appetite hormone regulation, immune responses, and antioxidative characteristics. HEAT STRESS RESULTS IN THE PRODUCTION OF REACTIVE OXYGEN SPECIES (ROS) ROS production increases when a bird experiences heat, triggering and modulating cell signaling activities. During severe heat stress, ROS production in mitochondria overwhelms antioxidant reserves, resulting in oxidative damage to proteins, lipids, and DNA. Acute heat stress results in ROS production, which antioxidant enzymes could neutralize. Chronic heat stress results in excessive ROS generation, further producing oxidative injury. Mojca Osredkar Mergole, DVM MSc Global Technical Manager – Poultry Delacon Biotechnik GmbH
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