饲料中添加不同浓度四环素对乌鳢生长性能、肠道菌群组成和组织形态的影响

Effects of Dietary Different Concentrations of Tetracycline on Growth Performance,Intestinal Microbiota Composition and Morphology of Channa argus

在与肠道微生态有关的营养代谢研究中,通常向饲料中添加抗生素抑制肠道菌群的生长,以研究肠道菌群与宿主营养代谢的相互关系,但往往忽略抗生素本身对试验动物营养代谢及肠道健康等方面的影响。本试验旨在探讨饲料中添加不同浓度四环素对乌鳢生长性能、肠道菌群组成和组织形态的影响,为相关研究提供参考。选择体质量[(9.43±0.12)g]相近、体格健壮的乌鳢幼鱼360尾,随机分为3组,每组设4个重复,每个重复30尾鱼。对照组(D1组)投喂基础饲料,试验组(D2、D3组)分别投喂在基础饲料中添加0.5和1.0 mg/kg四环素的试验饲料。试验期30 d。结果表明:1)D2和D3组的增重率、特定生长率和成活率显著低于D1组(P<0.05),D3组的饲料系数显著高于D1组(P<0.05)。2)D3组的肠道菌群操作分类单元(OT U)数量显著低于D1组(P<0.05)。D2和D3组的Sobs指数、ACE指数、Shannon指数显著低于D1组(P<0.05),Sim pson指数显著高于D1组(P<0.05)。3)饲料中添加不同浓度四环素降低了肠道中厚壁菌门(Firmicute)、芽孢杆菌科(Bacillaceae)、假单胞菌科(Pseudomonadaceae)、乳酸乳球菌属(Lactococcus)、土芽孢杆菌属(G eobacillus)和芽孢杆菌属(Bacillus)的比例,但增加了变形菌门(Proteobacteria)、链球菌科(Streptococcaceae)、莫拉菌科(Moraxellaceae)、链球菌属(Streptococcus)、明串珠菌属(Leuconostoc)和不动杆菌属(A cinetobacter)的比例。4)D1组的肠道绒毛高度显著高于D2和D3组(P<0.05),D3组的肠道肠壁厚度和绒毛宽度显著低于D1组(P<0.05)。由此可见,长期(30 d)的四环素应激易导致乌鳢肠道微生态紊乱以及肠道组织严重受损,且进一步引起乌鳢增重率、特定生长率和成活率下降,饲料系数升高。

In the study of nutrient metabolism related to intestinal microecology,antibiotics were usually used to inhibit the growth of intestinal microbiota,in order to study the relationship between intestinal microbiota and host nutrient metabolism,but the effects of antibiotics on the nutritional metabolism and intestinal health of experimental animals were often ignored. This experiment was aimed to investigate the effect of dietary different concentrations of tetracycline on growth performance,intestinal microbiota composition and morphology of Channa argus,to provide reference for related research. A total of 360 strong and healthy juvenile Channa argus with similar body weight [(9. 43 ± 0. 12) g] were randomly divided into 3 groups with 4 replicates per group and 4 fish per replicate. Fish in the control group(group D1) were fed a basal diet,and others in experimental groups(groups D2 and D3) were fed basal diets supplemented with 0.5 and 1.0 mg/kg tetracycline,respectively. The experiment lasted for 30 days. The results showed as follows: 1) the weight gain rate,specific growth rate and survival rate of groups D2 and D3 were significantly lower than those of group D1(P <0.05),the feed conversion ratio of group D3 was significantly higher than that of group D1(P < 0. 05). 2)The intestinal operational taxonomic units(OTU) number of D3 was significantly lower than that of group D1(P<0.05). The Sobs index,ACE index and Shannon index of groups D2 and D3 were significantly lower than those of group D1(P < 0. 05),and the Simpson index was significantly higher than that of group D1(P <0.05). 3) Dietary different concentrations of tetracycline decreased the proportion of intestinal Firmicute,Bacillaceae,Pseudononadaceae,Lactococcus,G eobacillus and Bacillus,but increased the proportion of Proteobacteria,Streptococcaceae,Moraxellaceae,Streptococcus,Leuconostoc and Acinetobacter. 4) The intestinal villus height of groups D1 was significantly higher than that of groups D2 and D3(P<0.05),and the intestinal wall thickness and villus width of group D3 was significantly lower than that of group D1(P < 0.05).In conclusion,long-term(30 d) tetracycline stress can result in the microecological disorder and serious damage of intestinal tissue,which further cause the weight gain rate,specific growth rate and survival rate of Channa argus decrease,and feed conversion ratio increase.