This study evaluated the effects of treated walnut green husk (WGH) on growth performance, 26 cecal microflora, jejunal morphology, nutrient digestibility, blood biochemistry, and meat quality 27 in broiler chickens. A total of 180 day-old Ross 308 broilers were allocated to three dietary 28 treatments with six replicates (10 birds per cage) for 42 days. Treatments included a basal diet 29 (control), the basal diet with 2.1 g/kg fermented WGH (FWGH), and the basal diet with 2.0 g/kg 30 WGH plus 0.1 g/kg multi-enzyme (EWGH). FWGH and EWGH improved broiler growth 31 performance during the grower, finisher, and overall periods, demonstrated by lower feed 32 conversion ratio and greater European production efficiency index, with FWGH showing slightly 33 superior effects. A relative improvement in body weight gain was observed in both treated groups 34 compared with the control group. Both treatments reduced cecal total aerobic bacteria, whereas 35 FWGH increased Lactobacillus spp. and decreased Clostridium perfringens. Jejunal villus height 36 increased in both groups, while villus surface area improved in FWGH. Diets containing FWGH 37 and EWGH significantly increased the apparent ileal digestibility of dry matter compared with the 38 control. Moreover, organic matter digestibility was significantly improved by FWGH, whereas ash 39 digestibility remained unaffected. FWGH and EWGH diets modulated blood parameters by 40 increasing lymphocyte (L) percentage and reducing WBC counts, heterophil percentage (H), H:L 41 ratio, plasma total cholesterol, low-density lipoprotein, and Alkaline phosphatase, with FWGH 42 also elevating low-density lipoprotein and reducing alanine transaminase. FWGH and EWGH 43 improved meat quality by reducing breast muscle press loss and thigh muscle malondialdehyde, 44 while EWGH additionally decreased malondialdehyde and increased pH in breast muscle, as well 45 as enhanced water-holding capacity and pH in thigh muscle compared with the control. Meat 46 proximate composition and color were unaffected. Overall, dietary inclusion treated-WGH 47 (FWGH and WGH with multi-enzyme) improved growth performance, intestinal health, nutrient 48 digestibility, blood lipid profile, and meat quality in broiler chickens, with FWGH showing slightly 49 superior effects.
