The Mechanisms Involved in the Decreased Egg Production in Chicken at High Ambient Temperatures (Review)

Effect of Adding Natural Antioxidants in Compared to Vitamin E to the Diet on the Lipid Profile and Antioxidant Status of Laying Hens

“…This is known as the gonadotrophic-pituitary-hypothalamic axis secretion. It also involves both of the hormones corticosterone decreasing follicular development in the ovary by reducing the availability of vitellogenin [5]. Because of this, it has been noted that large companies are currently implementing several strategies for changing the nutritional diets of chickens by the productive state and public health.…”

Individual and Combining Effect of Adding Astaxanthin and Magnolol Compared to Vitamin E to the Diet on Productive Performance and some Indicators of Oxidative Stress and Liver Enzymes in Laying Hens Serum

“…In laying hens productive performance and the quality of eggs produced are closely related to ovarian performance and one of the most basic factors causing ovarian damage is oxidative stress which is associated with high productivity and ovarian aging [1,2], as it is noted in the fourth week of laying eggs, the production rate reaches 50%, and the peak of egg production in the next three or four weeks reaches 90% to 97%, then the level of egg production decreases significantly after that, which seriously reduces the productive life of laying hens [3,4], it can be seen that the levels of egg production are negatively associated with age and the longevity of the productive life of the ovary is the main determinant of its function the liver also plays a key role in ovulation and production as does the ovary with a decrease in antioxidant capacity reproductive hormone levels and the development of 1252 (2023) 012124 IOP Publishing doi:10.1088/1755-1315/1252/1/012124 2 follicles this leads to a decrease in the synthesis of yolk precursors [5,6], also during egg production it was found that the liver produces large amounts of lipoproteins yolk proteins and lipids which are processed into yolk precursors that are transported through the blood to the ovaries to promote oocyte maturation so their levels can affect egg production [7], so it is necessary Interest in the mechanism of action of the liver-blood-ovary axis to increase the duration of the reproductive cycle in laying hens, as one of the main causes of aging is oxidative stress and the large accumulation of reactive oxygen species (ROS) with age that causes oxidative damage to the liver and ovaries and leads to a decrease in reproductive hormone levels and synthesis yolk precursor which is the direct cause of decreased egg production [8,9], In addition, it was found that the temperature from 19-22 C ° is ideal for performing the vital activities of laying hens however it was found that exposure to high ambient temperatures for laying hens for a long time than this rate causes a serious imbalance in the thermal balance of the body of laying hens and the inability of the body to get rid of heat excess and thus causes a decrease in feed consumption egg production and quality and disturbance in the reproductive system as a result of heat stress, which causes a decrease in the level of blood flow to enhance peripheral circulation in addition to that a decrease in the ability of the intestine to absorb nutrients and suppressive effects on the adrenal gland axis by the hormones prolactin and corticosterone and this causes suppression for follicular growth in the ovary by corticosterone through a decrease in vitellogenin availability and inhibition of secretions of the hypothalamic-pituitary-gonadal axis, including inhibition of the secretion of gonadotropin-releasing hormone (GnRH) which is secreted from the hypothalamus, which inhibits the secretion of gonadotropin-stimulating hormones (LH and FSH) from the anterior lobe of the pituitary gland [10,11].…”