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Original Research



Vol 18, No 10 ( 2023 )   |  DOI: 10.5281/zenodo.10069216   |   Author Affiliation: General Directorate of Agriculture, Ministry of Agriculture & Water Resources /Duhok-Iraq .   |   Licensing: CC 4.0   |   Pg no: 1481-1501   |   Published on: 26-10-2023


Many research have examined the negative effects of heat stress on poultry productivity since environmental stressors are commonplace globally. It has been demonstrated that heat stress has a deleterious impact on the productivity and well-being of laying hens and broilers. To better understand the fundamental mechanisms underlying the detrimental effects of heat stress on chickens and to create efficient therapies, more research is still necessary. Because of the recent detrimental effects of heat stress (HS), the most difficult environmental stressor on birds, there has been much concern over the decades-long increase in poultry production to meet the rapidly rising demand and ensure food security. In response, the chicken business has implemented a variety of environmental initiatives, involving making use of modern ventilation systems and ecologically controlled sheds. But these are not sustainable solutions, and they are extremely costly for landowners to implement. The negative consequences of HS include stunted growth, deteriorating meat quality due to decreased water-holding capacity, increased pH, and increased drip loss in meat, which alters the typical color, flavor, and texture of chicken meat. By reducing protein synthesis and increasing unwanted fat in meat, HS lowers the level of quality of meat. Previous research indicates that HS alters the effects of heat-shock proteins, insulin growth factor-1, and myogenic regulatory variables, therefore affecting the growth and development of skeletal muscle. This article concentrates on three primary areas: (1) determining the mechanism of heat stress that leads to the loss of quality and meat production in chickens; (2) discussing the physiological, metabolic, and genetic changes caused by HS that cause the global poultry industry to suffer; and (3) identifying research gaps that need to be filled in future studies. One of the most difficult environmental conditions that negatively affect the poultry industry worldwide is heat stress. The main reason broiler chicken strains are susceptible to heat anxiety is due to the fact that they lack sweat glands. The goal of the current study was to find out how heat stress affected the growth performance and bio-physiological traits of Cobb, Hubbard, and Arbor Acres broiler hybrids during the summer, when Egypt's environmental conditions were revealed. Three hundred and one day old birds, or one hundred from each hybrid, were fostered in identical circumstances with respect to water, food, and other factors on the same day. Vaccinations, medications, and breeding practices were utilized from the beginning to the moment of killing birds. The three strains—"Cobb, Hubbard, and Arboretum Acres"—were split into twelve groups by chance. Each group received two treatments—"control group and heat exposed group"—two duplicates, and twenty-five chicks. The control group experienced an environmental temperature of 32°±2 Celsius degree and a relative humidity of 50±5 percentage during housing, and the heat stressed group experienced an environmental temperature of 40°±2 Celsius degree and a relative humidity of 20±5 percentage. The weight of the body, weight gain, and edible and inedible portions of the carcass (carcass, thigh, drum, breast muscles, and giblets) and the weight of the head, legs, blood, and other inedible parts of the carcass were recorded for the heat-stressed group and the control group. The weight of lymphatic organs like the spleen, thymus, and bursa was also measured. The Cobb strain demonstrated superior growth performance and carcass characteristics under heat, according to our most recent findings. Stress situation, but the Arbor Acres strain is thought to be the strain to choose because it didn't significantly impact the user's rectal temperature like other strains that were exposed to heat. The most viable strain is the Arbor Acres strain in both the treated and control groups. In comparison to the group exposed to heat and other strains, the bursa weight of the control group and the Hubbard strain increased. In comparison to various varieties of broiler chicken, it was determined that the Cobb strain performed most effectively under heat stress.


Heat Stress (Hs), Birds, Poultry, Chicken, Strains, Quality.