Antioxidant status and content of vitamins A and E in broiler chickens under the influence of technological factors

Intensive industrial breeding of broiler chickens is accompanied by the action of a complex of technological factors, in particular, feed changes, vaccination and growth intensity, which in critical age periods can lead to a violation of the pro-oxidant-antioxidant balance. The aim of the study was to assess the functional state of the antioxidant system and the content of vitamins A and E in broiler chickens under the action of a complex of technological factors in an industrial housing system. The study was conducted on 14-day-old Cobb-500 crossbred broiler chickens. A control and experimental group of 25 heads each were formed. In the chickens of the experimental group, 48 hours after the effect of a complex of technological factors (changing the feed from starter to grower-1 on the 12th day of growing and vaccination against infectious bronchitis on the 13th day using the IB88 vaccine), the content of TBA-active products, the activity of superoxide dismutase, catalase and glutathione peroxidase, as well as the concentration of vitamins A and E in the blood were determined. It was established that 48 hours after the effect of the complex of technological factors, early oxidative stress developed in broiler chickens, which was manifested by an increase in the content of TBA-active products by 2.43 times (P < 0.05) compared to the control. At the same time, functional stress of the enzymatic link of the antioxidant system was established, which was characterized by a decrease in the activity of superoxide dismutase by 14.5 %, catalase by 28.9 % and glutathione peroxidase by 11.1 %. Analysis of the non-enzymatic link of antioxidant protection showed a decrease in vitamin E concentration by 22.6 % in experimental chickens, while the proportion of birds with α-tocopherol concentration below the physiological norm (2.5 μg/ml) increased from 4.0 % in the control to 60.0% in the experimental group. The content of vitamin A was characterized by an increase in chickens of the experimental group by 48.3% compared to the control and significant fluctuations in indicators, which presumably reflects its redistribution and mobilization from the depot in response to metabolic and immune loads. The results obtained confirm that the content of TBA-active products, catalase and superoxide dismutase activity, as well as the concentration of vitamin E are informative sensitive markers for early diagnosis of technological (oxidative) stress in broiler chickens under conditions of intensive industrial cultivation.