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Additives The use of phytogenic feed additives to mitigate the negative impact of heat stress in broilers
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by Manu de Laet, CTS, Delacon Biotechnik GmbH
he demand for poultry meat is increasing globally as a result of increasing population and popularity. Poultry meat is a very economical source of high-quality protein that is accessible in most regions across the globe. The predominant areas of increased demand, however, are in (sub)tropical regions where not only high temperatures but, also, high humidity levels have negative impacts on the efficiency of poultry production. The genetic factors that have been selected for growth and metabolic efficiency in broilers make them susceptible to heat stress. Faster growing breeds are more sensitive than slower growing breeds, males are more prone to reduced performance than females, and the negative effects of heat stress are increased with age.
Heat and humidity reduce performance
Heat stress is characterised as an imbalance between heat production and heat loss. Birds are unable to maintain thermoneutrality due to the environmental impact of both heat and humidity. The duration of heat stress (acute versus chronic,) the nature of heat stress (cyclic versus constant), and temperaturehumidity index (THI) determine the severity of the effect on production performance. Physiologic thermoregulation mechanisms, both to reduce heat production and to expedite heat loss, can lead to reduced production efficiency and increased mortality. Decreased activity and feed intake can lead to nutrient deficiencies and panting which can lead to respiratory alkalosis and acid/base imbalance. In addition, increased oxidative damage, inflammation, reduced gut integrity, and an increase of stress hormone production 84 | May 2020 - Milling and Grain