复合益生菌对白羽肉鸡肌肉品质的影响及作用机理

【目的】探究饮水中添加复合益生菌制剂（地衣芽孢杆菌、枯草芽孢杆菌和丁酸梭菌）对肉鸡肌肉品质的影响及作用机理。【方法】试验随机选取360只1日龄白羽肉仔鸡，随机分为3个处理组：对照组（CON），正常饮水；低剂量益生菌组（LG），饮水添加0.2%复合益生菌；高剂量益生菌组（HG），饮水添加0.4%复合益生菌，试验为期42 d。【结果】与CON组相比，LG组和HG组显著增加肉鸡7、35和42 d平均体重，显著提高HG组肉鸡21-28、28-35、35-42阶段的平均日增重（P<0.05），LG组仅显著提高35-42阶段平均日增重；显著提高胸肌45 min、24 h、48 h红度和24 h黄度，降低24 h和48 h亮度及48 h滴水损失和蒸煮损失。HG组胸肌粗蛋白和粗脂肪含量显著高于CON组，而LG组差异不显著；两组均可降低胸肌灰分含量。添加复合益生菌可显著提高总抗氧化能力（total antioxidant capacity，T-AOC），而总超氧化物歧化酶（total-superoxide dismutase，T-SOD）、过氧化氢酶（catalase， CAT）含量有上升趋势；显著上调CAT、SOD-1、Keap1和Nrf2基因表达，且HG组SOD-2、HO1显著高于LG组。LG组和HG组显著提升21 d和42 d盲肠乙酸、丙酸、丁酸和戊酸浓度。【结论】饮水添加复合型益生菌增强肉鸡生长性能、肌肉品质、抗氧化和短链脂肪酸含量，且HG组作用效果优于LG组。

Probiotic mixture improves meat quality of white feather broilers

Objective] To investigate the effect of supplementing a probiotic mixture (Bacillus licheniformis, B. subtilis, and Clostridium butyricum) in drinking water on the meat quality of broilers and explore the underlying mechanism. Methods] A total of 360 1-day-old white feather broilers were randomly selected and assigned to control (CON, normal drinking water), low-dose probiotic (LG, drinking water supplemented with 0.2% probiotic mixture), and high-dose probiotic (HG, drinking water supplemented with 0.4% probiotic mixture) groups. The experiment lasted for 42 days. Results] Compared with the CON group, the LG and HG groups showed increased average body weight on days 7, 35, and 42. The HG groups increased average daily gain during days 21-28, 28-35, and 35-42, while the LG groups increased average daily gain during days 35-42. LG and HG significantly increased the chest muscle redness at the time points of 45 min, 24 h, and 48 h and the chest muscle yellowness at the time point of 24 h, decreased the brightness at 24 h and 48 h and the dripping and cooking loss at 48 h. The HG group had higher content of crude protein and crude fat in chest muscle than the CON group and no significant difference compared with the LG group. Both LG and HG groups reduced the ash content of chest muscle. The addition of the probiotic mixture significantly increased total antioxidant capacity (T-AOC), while the levels of total-superoxide dismutase (T-SOD) and catalase (CAT) had an increasing trend. The expression levels of CAT, SOD-1, Keap1, and Nrf2 were significantly up-regulated, and the HG group had higher expression levels of SOD-2 and HO-1 than the LG group. The concentrations of acetic acid, propionic acid, butyric acid, and valeric acid in cecum on days 21 and 42 significantly increased in LG and HG groups. Conclusion] The probiotic mixture enhanced the growth performance and meat quality of broilers by increasing the levels of antioxidant activity and short-chain fatty acids, and the HG group outperformed the LG group.