低聚壳聚糖季铵盐的体外抑菌作用及其对肉鸡生产性能、免疫和抗氧化功能的影响

Antibacterial activity of quaternized chitooligosaccharide and its effects on growth performance, immunity, and antioxidant function of broilers

旨在研究低聚壳聚糖季铵盐(QCOS)的体外抑菌性能及其对肉鸡生产性能、肠道菌群、免疫和抗氧化功能的影响。通过在不同pH值、时间条件下添加不同水平QCOS,体外评价其抗菌性能;将320只1日龄健康AA肉鸡随机分成5组(每组8个重复,每个重复8只):对照组饲喂基础饲粮,金霉素组在基础饲粮中添加50 mg/kg金霉素(有效含量计),添加QCOS的试验Ⅰ、Ⅱ、Ⅲ组分别在基础饲粮中添加2.5、5和10 mg/kg的QCOS,试验期42 d。结果显示:QCOS对大肠杆菌的最小抑菌浓度和最小杀菌浓度分别为0.01%和0.5%,杀菌率随培养时间延长或pH值降低而提高。与对照组相比,QCOS具有降低肉鸡料重比的趋势(P<0.1),提高肉鸡盲肠内容物中乳酸杆菌含量(P<0.05),降低回肠黏膜的丙二醛(MDA)含量(P<0.05);试验Ⅱ、Ⅲ组均提高肉鸡回肠黏膜的总超氧化物歧化酶(T-SOD)活性及免疫球蛋白G(IgG)、免疫球蛋白M(IgM)含量;试验Ⅲ组提高了肉鸡空肠黏膜的IgG、IgM含量(P<0.05)。与金霉素组相比,QCOS提高了肉鸡空肠、回肠黏膜的分泌型免疫球蛋白A(SIgA)、IgG、IgM含量(P<0.05);试验Ⅲ组提高了肉鸡回肠的T-SOD活性,降低十二指肠、回肠黏膜的MDA含量(P<0.05)。结果表明:QCOS对禽大肠杆菌具有良好的抑菌效果;可提高肉鸡盲肠乳酸杆菌含量及提高肠道黏膜免疫机能和抗氧化性能,且作用效果优于金霉素。

The purpose of this experiment was to study the antibacterial properties of quaternized chitooligosaccharide(QCOS) in vitro and its effects on the growth performance, intestinal flora, immunity, and antioxidant function of broilers. The experiments were carried out by supplementing different levels of QCOS to diet under different pH and time conditions so as to evaluate the antibacterial properties of QCOS. A total of 320 one-day-old healthy broiler chicks were used and randomly allocated into five groups with 8 replicates of 8 broilers each. The control group was fed the basal diet, the chlortetracycline control group was fed with a diet supplemented with 50 mg/kg chlortetracycline(effective content), and the test groups Ⅰ,Ⅱ and Ⅲ were fed with a diet added with 2.5, 5 and 10 mg/kg QCOS, respectively. The results showed as follows: The minimum concentrations of QCOS for bacterial inhibition and destroy were 0.01% and 0.5%, respectively, and its bactericidal rate increased with the extension of culture time or decrease in pH value. Compared with the control group, QCOS supplemented groups had a tendency to reduce the feed/gain ratio(P<0.1), increase the proportion of Lactobacillus in their cecal contents(P<0.05), and reduce the content of malondialdehyde(MDA) in ileal mucosa(P<0.05). The test groups Ⅱ and Ⅲ had an increase in the total superoxide dismutase(T-SOD) activity and the content of immunoglobulin G(IgG), immunoglobulin M(IgM) in the ileal mucosa. The test group Ⅲ had an increase in the content of IgG and IgM in the jejunal mucosa(P<0.05). Compared with the chlortetracycline group, the QCOS groups had an increase in secretory immunoglobulin A(SIgA), IgG and IgM concentrations in the jejunum and ileum mucosa( P<0. 05),and the test group Ⅲ had an increase in the T-SOD activity in the ileum mucosa and decrease in the MDA content in the duodenum and ileum mucosa( P<0. 05). The above results indicated that QCOS had a good antibacterial effect on avian Escherichia Coli,improving the intestinal immunity and antioxidant capacity of broilers,increasing the amount of Lactobacillus in their cecal contents,and exerting better effects than chlortetracycline.