Impact of climate change on thermoregulation, blood attributes and production performance in laying hens

The objective of the study was to assess the impact of climate change, expressed through the Temperature Humidity Index (THI), on physiological responses, including body temperature, blood parameters, and production indicators on laying hens, the Novogen Brown strain, from the ۲۲nd to ۳۴th weeks of age. The experiment was conducted in northern Algeria during the summer season in two separate buildings. The first building, which housed approximately ۸۵,۰۰۰ laying hens, was modern with a controlled environment (control group). On the other hand, the second building, housing approximately ۴۰,۰۰۰ laying hens, was exposed to natural variations in the external climate (experimental group). Additionally, the temperature fluctuated between ۲۵.۲ and ۳۹.۴°C, while humidity ranged from ۵۴.۳ to ۶۴.۵%. The overall trend of the results revealed notable variations in the parameters studied in the experimental group. Body temperature showed a significant (P<۰.۰۰۱) increase of +۰.۹۹°C. Blood parameters also revealed significant (P<۰.۰۰۱) increases; the amplitudes were +۰.۱۸ for the heterophil/lymphocyte ratio, +۱.۸۲ng/mL for corticosterone, and +۵.۰۶ng/mL for cortisol. Furthermore, production performance showed significant reductions (P<۰.۰۰۱) in egg weight (-۴.۶۷g) and laying rate (-۶.۷۷%) with an increase of +۱.۷۵% in the egg breakage rate (P<۰.۰۰۱). The results of the present study highlighted the stress that laying hens may experience due to climate change, particularly when hens are housed in buildings that do not meet the standards. These situations could compromise the sustainability of the poultry industry and threaten food security, given the importance of poultry products in the human food chain.

کلیدواژه ها:

Climate Change ، laying hens ، thermoregulation ، blood markers ، production