The influence of the inclusion of walnut leaves in the diet of laying hens on the vitamin availability and antioxidant properties of eggs

Goal. To assess the effect of a phytoadditive from walnut leaves included in the diet of chickens on the vitamin availability and antioxidant properties of eggs and their hatching qualities. Methods. The research was conducted on four groups of laying hens (total number — 144 birds), each of which received its diet: the control group, without the addition of phytoadditive (K); a group of chickens whose diet included a synthetic antioxidant (D1); two experimental groups to which 1% (D2) and 2% (D3) walnut leaves of the Bukovynskyi variety were added to the dry feed. The content of carotenoids, vitamins A and E was determined on the 30th, 60th, and 120th day of the experiment, and the antioxidant activity and incubation qualities of the eggs were evaluated at the end of the experiment. Results. It was established that the addition of walnut leaves to the diet of poultry in the amount of 1% and 2% of the total volume of feed significantly increased the content of carotenoids and vitamins A and E in egg yolks, which indicated an improvement in their nutritional value. The maximum increase in the amount of carotenoids (20.83 µg/g) and vitamin E (152.0 µg/g) was observed in group D3 after 120 days of the experiment. The use of a phytoadditive significantly increased the antioxidant activity of feed and eggs in groups D2 and D3 compared to the control and the group with a synthetic antioxidant (D1). The best egg hatchability (93.7%) was observed in chickens of group D2, and this was evidence that the optimal amount of walnut leaves was 1%. Conclusions. The use of walnut leaves in the diet of laying hens had a positive effect on the oxidative capacity of the feed, increased the content of vitamins, and improved the antioxidant properties of eggs and their hatching qualities. In addition, this dietary supplement improved the nutritional value of eggs and the reproductive function of poultry.