Diagnosis of oxidative stress in laying hens

Abstract

Stresses in poultry are widespread; they cause a decrease in egg production and meat productivity, severe pathomorphological changes in organs and tissues, often leading to the death of a sick bird. When diagnosing oxidative stress in laying hens at the age of 5-6 months, it is important to determine such indicators in the blood serum as vitamins E, C, coenzyme Q10 and hormones - adrenocorticotropic hormone (ACTH) and cortisol. For this purpose, control and experimental groups of laying hens of the Haysex Brown egg direction at the age of 5-6 months of 20 heads each were selected. Laying hens were kept in a cage battery. Technological stress was modeled by changing the planting density of chickens of the experimental group. At the beginning of the studies, the planting density of the bird was 0.25 m² per head. After 2 months of experiments, the planting density was reduced to 0.4 m² per chicken. In the laying hens of the control group, the planting density did not change during the entire time of the experiments and was 0.4 m² per head. It was found out that with the development of a stress reaction, the content of vitamins E, C and Coenzyme Q10 in the blood of chickens of the experimental group sharply decreases compared to the control group. The maximum decrease was on the 30th day of experiments with a planting density of 0.25 m². When the planting density decreases to 0.4 m², there are slight shifts in the studied indicators in the direction of increase. These changes should be considered as the beginning of the development of an adaptive reaction and a decrease in the level of oxidative stress in chickens.  The change in the level of thyrotropin (TSH) and thyroxine (T4) occurs at the level of indicators of the control group and cannot serve as a diagnostic criterion of oxidative stress in laying hens.