植物提取物及其复合物对鸡源致病菌的体外抑菌作用

本研究选取10种具有较强抑菌作用的植物提取物,研究其对鸡源致病菌(鸡大肠杆菌和鸡沙门氏菌)的体外抑菌作用,并分别筛选出对2种致病菌有较强抑菌作用的3种植物提取物,将其按不同比例复配,以获得抑菌效果更强的复合植物提取物。本研究分为2个试验。试验1:共设11个组,分别为百里香精油、牛至精油、肉桂精油、大蒜油、黄芩黄酮、竹叶黄酮、黄芪多糖、小檗碱、苦参碱和绿原酸和金霉素组(阳性对照组),每组6个重复,采用牛津杯法测定植物提取物对大肠杆菌和沙门氏菌的抑菌作用。试验2:根据试验1的结果,选取对大肠杆菌抑菌效果较好的肉桂精油、苦参碱和绿原酸3种植物提取物,分别按照不同浓度比例进行两两和3种植物提取物复配,用牛津杯法测定复合物对大肠杆菌的抑菌作用,同时分别设相应浓度的3种单一植物提取物为对照组,共20个组,每组6个重复;选取对沙门氏菌抑菌效果较好的竹叶黄酮、黄芩黄酮和肉桂精油3种植物提取物,用牛津杯法测定不同浓度比例的复合物和相应浓度的单一植物提取物(对照组)对沙门氏菌的抑菌作用,共17个组,每组6个重复;根据以上结果,研究了竹叶黄酮和肉桂精油按不同浓度比例复配对沙门氏菌的抑菌作用,以筛选最佳复配比例,共15个组,每组6个重复。结果表明:5种植物提取物对大肠杆菌有抑菌作用,其抑菌作用从大到小依次为肉桂精油、苦参碱、绿原酸、百里香精油、牛至精油;8种植物提取物对沙门氏菌有抑菌作用,其抑菌作用从大到小依次为竹叶黄酮、黄芩黄酮、肉桂精油、苦参碱、绿原酸、牛至精油、百里香精油、大蒜油。与肉桂精油对照组相比,肉桂精油、苦参碱和绿原酸两两或3种植物提取物复配不能显著增强对大肠杆菌的抑菌作用(P0.05);竹叶黄酮和肉桂精油复配可显著增强对沙门氏菌的抑菌作用(P0.05),且在浓度比例为25∶150(1∶6)时抑菌作用达到最大。由此可见,10种植物提取物中,对大肠杆菌抑菌效果较好的3种植物提取物为肉桂精油、苦参碱和绿原酸,但这3种植物提取物复合物的抑菌作用并不大于单一肉桂精油;对沙门氏菌抑菌效果较好的3种植物提取物为竹叶黄酮、黄芩黄酮和肉桂精油,竹叶黄酮和肉桂精油复配增强了抑菌效果,且复配比例为1∶6时对沙门氏菌的抑菌作用最大。

Bacteriostatic Effects of Plant Extracts and Their Compounds on Chicken Pathogenic Bacteria in vitro

In this study,ten kinds of plant extracts with stronger bacteriostatic effects were selected to investigate their bacteriostatic effects in vitro on the chicken pathogenic bacteria (Escherichia coli and Salmonella),and three kinds of plant extracts with stronger bacteriostatic effects on one of the two pathogens were selected,respectively,and compounded in different proportions to obtain the plant extract compounds with stronger bacteriostatic effects.This study was divided into two trials.Experiment 1: eleven groups thyme oil,oregano essential oil,cinnamon essential oil,garlic oil,skullcapflavone,bamboo leaf flavonoids,astragalus polysaccharides,berberine,matrine,chlorogenic acid and aureomycin (the positive control) group] were arranged with six replicates per group,and the bacteriostatic effects of plant extracts on Escherichia coli and Salmonella were determined by Oxford cup method.Experiment 2: according the results of experiment 1,three kinds of plant extracts (cinnamon essential oil,matrine and chlorogenic acid) with stronger bacteriostatic effects on Escherichia coli were screened out and compounded in different concentration ratios,respectively,and bacteriostatic effects of plant extract compounds on Escherichia coli were determined by Oxford cup method.At the same time,the control groups of three plant extracts in corresponding concentrations were arranged.There were twenty groups in total with six replicates per group.Three kinds of plant extracts (bamboo leaf flavonoids,skullcapflavone and cinnamon essential oil) with stronger bacteriostatic effects on the Salmonella were screened out,and bacteriostatic effects of the plant extract compounds in different concentration ratios and three kinds of plant extracts in corresponding concentrations (control groups) on Salmonella were determined by Oxford cup method.There were seventeen groups in total with six replicates per group.According to the above results,bacteriostatic effects of the compounds of bamboo leaf flavonoids and cinnamon oil in different concentration ratios on Salmonella were determined,and the optimal proportion of compound was selected.There were fifteen groups in total with six replicates per group.The results showed that five kinds of plant extracts had bacteriostatic effects on Escherichia coli,and the order of their bacteriostatic effects from high to low was cinnamon essential oil,matrine,chlorogenic acid,thyme essential oil,oregano essential oil.In addition,eight kinds of plant extracts had bacteriostatic effects on Salmonella,and the order of their bacteriostatic effects from high to low was bamboo leaf flavone,skullcapflavone,cinnamon essential oil,matrine,chlorogenic acid,oregano essential oil,thyme oil,garlic oil.Compared with the cinnamon essential oil control group,the compounds of cinnamon essential oil,matrine and chlorogenic acid did not significantly improved the bacteriostatic effects on Escherichia coli (P>0.05).However,the compounds of bamboo leaf flavone and cinnamon essential oil significantly improved the bacteriostatic effects on Salmonella (P<0.05),and the bacteriostatic effects was the highest in the concentration ratio of 25∶150 (1∶6).In conclusion,among the ten kinds of plant extracts,three kinds of plant extracts with better bacteriostatic effects on Escherichia coli are cinnamon essential oil,matrine and chlorogenic acid,but the bacteriostatic effects of plant extract compounds is not stronger than that of cinnamon essential oil;and the three kinds of plant extracts with better bacteriostatic effects on Salmonella are bamboo leaf flavone,skullcapflavone and cinnamon essential oil,and the compounds of bamboo leaf flavone and cinnamon essential oil improve the bacteriostatic effects on Salmonella,and the bacteriostatic effects is the highest in the concentration ratio of 1∶6.