A New Insight into Cold Stress In Poultry Production.
Since growing animals are vulnerable to extreme temperature, climate changes become an important critical constraint to several species in the world. In poultry production, while heat stress has been a rising concern for producers and scientists, cold stress has also caused economic loss worldwide. In China, winter conditions and low temperature caused almost 20 million poultry deaths and an economic loss of 100 million in 2008. Early research in poultry exposed to acute cold stress has shown a clear suppression in development, survival and egg production
At the molecular level, an acute hypothermal condition significantly up-regulated gene expression of hepatic leptin and muscle UCP in 5-wk-old broilers. Exposure at 4 ° C for 24 hours resulted in changes in some genes involved in lipid metabolism in broilers pituitary. This suggests that cold stress can affect lipid metabolism. At younger age (7-14 days old), although a chronic cold stress (20 °C) did not affect body weights and feed intake, it significantly increased chick body heat production and avUCP gene expression in the leg muscle.
Birds exposed to cold stress had severely injured liver and increased gene expression of AMPKα–
PPARα pathway. Moreover, there is clear evidence that cold stress affects thyroid hormones
(T3 and T4) which play a key role in energy expenditure and body temperature homeostasis. Yet, the effect of cold exposure on growth performance is still controversial. Indeed, Baarendse and colleagues11 observed that moderate cold exposure during the early post-hatching period caused long-term negative effects on chicken growth performance.
Adv Food Technol Nutr Sci Open J. 2016; 2(1): 1-2. doi: 10.17140/AFTNSOJ-2-124
