日粮纤维水平对不同猪种肠道物理屏障和微生物的影响

Effects of dietary fiber levels on intestinal physical barrier and microbiota in different pig breeds

为研究日粮纤维水平对不同品种猪肠道形态、通透性和微生物的影响,按照2×4双因子设计,选择体质量约40 kg的健康二花脸猪和与二花脸猪相同生理阶段约65 kg的大白猪各24头随机分为4个处理组,分别饲喂基础日粮和7%、14%、21%麸皮替代基础日粮,每组6个重复,使用奥饲本全自动生产性能测定系统进行饲喂,每个重复1头猪。正试期28 d,试验结束时采集血液样品,分离血清用于血清内毒素、二胺氧化酶(DAO)和D-乳酸含量测定;屠宰采集盲肠和结肠中段样品进行形态学观察,采集空肠和结肠黏膜进行微生物16S rRNA基因拷贝数测定。结果表明:猪品种对血清内毒素含量、D-乳酸含量、空肠双歧杆菌丰度、盲肠隐窝深度、盲肠肠壁厚度、结肠肠壁厚度、结肠肌层厚度、结肠大肠杆菌和结肠乳酸杆菌丰度有显著影响(P<0.05)。日粮麸皮水平对血清DAO含量、D-乳酸含量和结肠大肠杆菌丰度有显著影响(P<0.05)。二花脸猪,与基础日粮对照相比,7%和14%麸皮替代日粮处理的D-乳酸含量显著升高(P<0.05),21%麸皮替代日粮处理的DAO含量显著升高(P<0.05),7%麸皮替代日粮处理的盲肠肌层厚度显著升高(P<0.05),21%麸皮替代日粮处理的盲肠肠壁厚度显著降低(P<0.05),7%麸皮替代日粮处理的结肠乳酸杆菌丰度显著升高(P<0.05),14%麸皮替代日粮处理的结肠大肠杆菌丰度显著降低(P<0.05)。大白猪,与基础日粮对照相比,14%麸皮替代日粮处理的DAO含量显著升高(P<0.05),14%和21%麸皮替代日粮处理的盲肠肠壁厚度显著增加(P<0.05),7%麸皮替代日粮处理的空肠双歧杆菌丰度显著降低(P<0.05),14%麸皮替代日粮处理的空肠双歧杆菌和结肠乳酸杆菌丰度显著降低(P<0.05)。综上所述,大白猪和二花脸猪在大肠形态、肠道通透性、空肠双歧杆菌丰度、结肠大肠杆菌丰度和结肠乳酸杆菌丰度等方面存在差异,日粮麸皮水平影响结肠大肠杆菌丰度。7%麸皮替代水平增大二花脸猪肠道通透性,但增加盲肠肌层厚度以适应纤维的消化,并增加结肠乳酸杆菌丰度促进肠道健康。14%麸皮替代水平会导致大白猪肠道通透性增大,盲肠肠壁增厚,空肠双歧杆菌和结肠乳酸杆菌丰度降低。

The aim of this experiment was to study the effects of dietary fiber levels on intestinal morphology,permeability and microbiota in different pig breeds.Based on 2×4 two-factor design,twenty-four Erhualian pigs(approximately 40 kg)and twenty-four Large White pigs(the same physiological stage as the Erhualian pig,approximately 65 kg)were selected and randomly divided into four treatment groups including control diet group,7%,14%and 21%wheat bran replaced basal diet with six replicates in each group and one pig per replicate.The pigs were fed by the Osborne testing stations system.After the 28-d trial,blood samples were collected and the serum was collected for analyses of endotoxin,diamine oxidase(DAO)and D-lactate.The middle sections of the cecum and colon were collected for histological analysis.Mucosal scrapings from the jejunum and colon were prepared for the detemination of 16S rRNA gene copy number.The results showed that pig breeds had significant effects on serum endotoxin content,D-lactate content,the abundance of Bifidobacterium in the jejunum,cecal crypt depth,intestinal wall thickness in the cecum,intestinal wall thickness in the colon,muscle thickness in the colon,the abundance of Escherichia coli and Lactobacillus in the colon(P<0.05).The level of wheat bran had significant effects on serum DAO content,D-lactate content and the abundance of Escherichia coli in the colon(P<0.05).For Erhualian pig,compared with the control group,7%and 14%wheat bran significantly increased D-lactate content(P<0.05),21%wheat bran significantly increased DAO content(P<0.05),7%wheat bran significantly increased the muscle thickness in the cecum(P<0.05),21%wheat bran significantly decreased intestinal wall thickness in the cecum(P<0.05),7%wheat bran significantly increased the abundance of Lactobacillus,14%wheat bran decreased the abundance of Escherichia coli in the colon(P<0.05).For Large White pig,compared with control group,14%wheat bran significantly increased DAO content(P<0.05),14%and 21%wheat bran significantly increased the intestinal wall thickness in the cecum(P<0.05),7%wheat bran significantly decreased the abundance of Bifidobacterium in the jejunum(P<0.05),14%wheat bran significantly decreased the abundance of Bifidobacterium in the jejunum and the abundance of Lactobacillus in the colon(P<0.05).In conclusion,there were differences between Erhualian pig and Large White pig in large intestine morphology,intestinal permeability,the abundance of Bifidobacterium in the jejunum,the abundance of Escherichia coli in the color,the abundance of Lactobacillus in the colon.The level of wheat bran affected the abundance of Escherichia coli in the colon.The 7%wheat bran increased intestinal permeability in Erhualian pigs.However,muscle thickness in the cecum was increased to odapt to the digestion of fiber,and the abundance of Lactobacillus in the colon was increased to improve intestinal health.The 14%wheat bran increased intestinal permeability and intestinal wall thickness in the cecum,and decreased the abundance of Bifidobacterium in the jejunum and Lactobacillus in the colon.