Aerial part of Tetrastigma hemsleyanum Diels et Gilg improved laying performance and egg quality by improving antioxidant capacity and intestinal health of early-stage laying hens

Tetrastigma hemsleyanum Diels et Gilg, a valued traditional Chinese medicinal herb, has been studied for its chemical composition and physiological functions, mainly in its roots. This study aimed to investigate the effect of aerial part of Tetrastigma hemsleyanum Diels et Gilg (ATH) on production performance, egg quality, antioxidant capacity, and intestinal health in early-stage laying hens. A total of 252 Hy-Line Brown hens at 19 wk of age were randomly allocated to 3 groups, each with 4 replicates of 21 hens (n=84 per group). The treatments were: 1) basal diet (CON group); 2) basal diet+1% ATH (ATH group); 3) basal diet+1% fermented ATH (FATH group). This experiment lasted for 6 wk, including a 1-wk adaptation period. Supplementation with ATH and FATH significantly increased the laying rate and decreased the feed conversion ratio ( P < 0.05). Albumen height and Haugh unit were significantly higher in the FATH group than in the ATH and CON group ( P < 0.05); Compared with the CON group, the ATH and FATH groups showed higher total superoxide dismutase (TSOD) activity in the liver and higher TSOD and catalase (CAT) activities and greater total antioxidant capacity (T-AOC) in the magnum ( P < 0.05); The FATH group also showed greater muscle thickness in the duodenum and ileum and greater villus height and villus height to crypt depth ratio in the jejunum than both the ATH and CON group ( P < 0.05); Both the FATH and ATH groups showed a lower relative abundance of potentially harmful bacteria, such as Desulfobacterota and Proteobacteria, and a higher abundance of beneficial bacteria, such as Bacteroidales_unclassified ( P < 0.05). These results indicated that dietary supplementation of ATH and FATH enhanced antioxidant capacity in the liver and magnum, improved intestinal morphology and cecal microbiota, and consequently improved the production performance and egg quality of early-stage laying hens. FATH showed more pronounced beneficial effects than ATH, particularly in intestinal morphology.