Effect of different dietary oil sources on the performance, egg quality and antioxidant capacity during the late laying period

This study investigated the effects of different dietary ratios of linseed and soybean oils on the performance, egg quality, and antioxidant capacity of late-phase laying hens. A total of 360 70-week-old Jinghong laying hens were randomly assigned to four groups of six replicates each, with 15 chickens per replicate. Diets with linseed oil to soybean oil ratios of 3:0 (T1), 2:1 (T2), 1:2 (T3), and 0:3 (T4) were fed for 4 weeks. No significant differences in egg weight, feed intake of laying hens, egg production, or feed-to-egg ratio (P > 0.05) were observed among the groups. Compared with the T4 group, the T2 group had a significantly higher number of 8-10 mm follicles. Moreover, albumen height and Haugh units were significantly higher in the T3 group than in the T4 group (P < 0.05), although significant differences were not observed among the T1, T2, and T3 groups. With an increase in linseed oil addition to the feed, the content of n-3 polyunsaturated fatty acids in chicken eggs significantly increased (P < 0.05). Compared to the T4 group, the addition of linseed oil to the diet significantly reduced the blood malondialdehyde content and increased the blood glutathione peroxidase (GSH-PX) and superoxide dismutase enzyme activity. The GSH-PX activity and total antioxidant capacity in the oviducts of the T3 group were significantly higher than those of the T4 group (P < 0.05). The protein expression levels of Nrf2, HO-1, and NQO-1 in the oviduct tissues were significantly higher in the T3 group than in the T4 group (P < 0.05). This study showed that a linseed oil to soybean oil ratio of 1:2 in the T3 group enhanced egg quality by reducing oxidative stress and improving the oviduct microenvironment.