苯甲酸和精油对肉鸡生长性能、抗氧化状态和肠道微生物群的影响

本研究开展了3个饲养试验，旨在探讨苯甲酸和精油单独或联合使用对肉鸡生长性能、肠道微生物含量及肝脏抗氧化性能的影响。试验1和2均选择1日龄肉鸡450只，分为3组，每组5个重复，每个重复30只。对照组均饲喂相同的基础日粮，试验1处理组肉鸡分别饲喂基础日粮添加1.5和3?g/kg苯甲酸，试验2处理组肉鸡分别饲喂日粮添加2和4?mg/kg精油。试验3选择1日龄肉鸡300只，分为2组，每组5个重复，每个重复30只，对照组饲喂基础日粮，处理组饲喂基础日粮添加1.5?g/kg苯甲酸和4?mg/kg精油。3个试验均开展42?d。结果：试验1，1.5?g/kg苯甲酸组较对照组和3?g/kg苯甲酸组显著提了21和42?d肉鸡的体重及1～21?d、22～42?d、1～42?d日增重（P＜0.05），同时1.5?g/kg苯甲酸组各阶段肉鸡料重比最低（P＜0.05）。与对照组相比，苯甲酸处理组显著提高了盲肠乳酸菌含量（P＜0.05），显著降低了盲肠大肠杆菌数量（P＜0.05）。试验2，基础日粮添加4?mg/kg植物精油组42?d肉鸡体重和日增重、盲肠乳酸菌含量（P＜0.05），料重比和盲肠大肠杆菌数量最低（P＜0.05）。同时，植物精油组较对照组显著提高了肝脏谷胱甘肽过氧化物酶（GSH-Px）和谷胱甘肽-S转移酶（GST）活性（P＜0.05），显著降低了肝脏丙二醛含量（P＜0.05）。试验3，处理组较对照组显著降低了嗉囊大肠杆菌数量（P＜0.05）。处理组肝脏谷胱甘肽过氧化物酶（GSH-Px）和和谷胱甘肽-S转移酶（GST）活性显著高于对照组（P＜0.05），但丙二醛含量显著降低（P＜0.05）。结论：日粮添加1.5?g/kg苯甲酸或4?mg/kg精油可以改善肉鸡生长性能，降低肠道有害微生物含量，而苯甲酸与精油无论是单独添加还是联合使用均可以提高肉鸡肝脏的抗氧化状态。 关键词]苯甲酸|精油|肉鸡|生长性能|抗氧化|微生物

Effects of benzoic acid and essential oils on growth performance,antioxidant status and intestinal microflora of broilers

Three feeding experiments were conducted to investigate the effects of benzoic acid and essential oils alone or in combination on growth performance,intestinal microbial content,and antioxidant performance of the liver of broilers.In experiment 1 and 2,4501-day-old broiler chickens were selected and divided into 3 groups with 5 replicates in each group and 30 chickens in each replicate.The control group was fed the same basic diet.Broilers in the treatment group 1 were fed the basic diet supplemented with 1.5 and 3 g/kg benzoic acid respectively,while broilers in the treatment group 2 were fed the basic diet supplemented with 2 and 4 mg/kg essential oil respectively.In experiment 3,300 broilers on a 1-day diet were divided into 2 groups with 5 replicates in each group and 30 in each replicate.The control group was fed the basic diet,while the treatment group was fed the basic diet supplemented with 1.5 g/kg benzoic acid and 4 mg/kg essential oil.All three trials were conducted for 42 days.Results:In experiment 1,1.5 g/kg benzoic acid group,compared with the control group and 3 g/kg benzoic acid group,the body weight of broilers at 21 and 42 d and daily weight gain at 1~21 d,22~42 d and 1~42 d were significantly increased(P<0.05),and the feed weight ratio of broilers at each stage in 1.5 g/kg benzoic acid group showed the lowest(P<0.05).Compared with the control group,the benzoic acid treatment group significantly increased the content of lactobacillus and significantly reduced the number of Cecal Escherichia coli(P<0.05).In experiment 2,broiler chickens added with 4 mg/kg essential oil on the basal diet at 42 d showed the lowest weight and daily weight gain,cecal lactobacillus content(P<0.05),feed weight ratio and number of cecal E.coli(P<0.05).At the same time,the activity of GSH-PX and GST in the liver was significantly increased in the plant essential oil group compared with the control group(P<0.05),and the content of malonaldehyde in the liver was significantly decreased in the plant essential oil group(P<0.05).In experiment 3,the quantity of E.coli in the treated group was significantly reduced compared with the control group(P<0.05).The activity of glutathione peroxidase(GSH-PX)and glutathione s-transferase(GST)in the treated group was significantly higher than that in the control group(P<0.05),but the content of malonaldehyde was significantly lower in the treated group(P<0.05).Conclusion:Adding 1.5 g/kg benzoic acid or 4 mg/kg essential oil to the diet can improve the growth performance of broilers and reduce the content of harmful microorganisms in the intestinal tract,while adding benzoic acid and essential oil alone or in combination can improve the antioxidant status of broilers’liver.