Lonicera flos and Cnicus japonicus extracts improved egg quality partly by modulating antioxidant status, inflammatory-related cytokines and shell matrix protein expression of oviduct in laying hens

This study was conducted to investigate the effects of Lonicera flos and Cnicus japonicus extracts (LCE) on the laying performance, egg quality, morphology, antioxidant status, inflammatory-related cytokines, and shell matrix protein expression of oviduct in laying hens. A total of 1,728 Roman Pink laying hens aged 73-wk-old were randomly assigned into 4 groups (18 replicates/group, 24 layers/replicate) fed basal diets supplemented with 0, 300, 500, and 1,000 mg of LCE per kg of diet, respectively. The trial lasted for 11 wk, including 2-wk adjustment period and 9-wk testing period. The results indicated that laying hens fed diets supplemented with LCE linearly increased egg weight, yolk color and shell thickness at wk 78 and albumen height, Haugh unit and shell thickness at wk 83 (P < 0.05). At wk 78, LCE groups linearly affected the hydrogen peroxide content in magnum (P < 0.05) and 300 mg/kg LCE groups had the highest catalase activity in isthmus (P < 0.05). At wk 83, LCE groups linearly reduced (P < 0.05) hydrogen peroxide content in the magnum and isthmus and malondialdehyde content in the uterus whereas increased catalase activity in isthmus (P < 0.05). Furthermore, LCE levels quadratically affected glutathione peroxidase activity in isthmus at wk 83 (P < 0.05). At wk 78, the mRNA expressions of inducible nitric oxide synthase and interferon-γ in isthmus and ovalbumin and ovocleidin-116 in uterus had linear effects in response to LCE levels (P < 0.05) and 1,000 mg/kg LCE group had the lowest mRNA expression of interleukin-6 in magnum (P < 0.05). At wk 83, LCE supplementation linearly decreased the mRNA expression of interleukin-1β, interferon-γ and tumor necrosis factor-α in magnum and tumor necrosis factor-α and inducible nitric oxide synthase in uterus (P < 0.05). It is concluded that LCE improved egg quality partly by modulating antioxidant status, inflammatory-related cytokines and shell matrix protein expression of oviduct in laying hens.