藏猪小肠形态、消化酶及微生物多样性研究

Intestinal morphology, digestive enzymes and bacterial diversity of Tibetan pigs

摘要:

[目的] 肠道是动物的主要消化器官，同时也是机体抵抗外源病原菌的重要屏障，已有研究表明，动物的品种、饲养方式、生长阶段均会影响动物的肠道菌群结构，但对舍饲和放牧饲养条件下藏猪的肠道菌群结构，以及藏猪和长白、约克与杜洛克三元杂交猪（DLY猪）的肠道菌群结构是否有差异，尚未见报道。[方法] 本研究选取6-7月龄的放牧藏猪、舍饲藏猪和DLY猪的小肠组织，分别采用组织切片法测定各试验猪的肠道形态、酶活性测定试剂盒测定肠道内容物的消化酶活性，高通量测序法测定肠道微生物。[结果] DLY猪小肠的肌层厚度和绒毛高度高于藏猪，而隐窝深度低于藏猪；舍饲藏猪和放牧藏猪的小肠形态没有显著变化。DLY猪小肠的胰蛋白酶活性高于藏猪，而淀粉酶活性低于藏猪。三组猪小肠微生物的优势菌门均为Proteobacteria、Firmicutes和Bacteroidetes；藏猪的优势菌属为Ralstonia和Escherichia，而DLY猪的优势菌属为Ralstonia和Bradyrhizobium，但含量却存在显著性差异。舍饲藏猪与放牧藏猪肠道菌群结构相似度较高，而藏猪与DLY猪肠道菌群结构相似度较低。[结论] 放牧藏猪、舍饲藏猪和DLY猪的小肠形态、消化酶活性和肠道菌群结构均存在显著性差异。

Abstract:

[Objective] The intestinal tract comprises the main digestive organs of animals and is an important barrier that confers organism resistance to exogenous pathogens. The intestinal flora of animals is reportedly related to animal species, feeding methods and growth stage. However, it is unclear whether the intestinal bacteria of house-feeding Tibetan, grazing Tibetan and Landrace, York and Duroc (DLY) three-way hybrid pigs differ. [Methods] The intestinal tissues of 6-month-old to 7-month-old grazing Tibetan, house-feeding Tibetan and DLY pigs were selected. The intestinal morphology of each pig was determined by tissue section method. The digestive enzyme activity of intestinal contents was determined by using an enzyme activity assay kit. The intestinal microbiota was examined through high-throughput sequencing technology. [Results] The muscular thickness and villus height of duodenum, jejunum and ileum of DLY pigs were significantly higher than those of Tibetan pigs. The crypt depth of the duodenum, jejunum and ileum of DLY pigs was significantly lower than that of Tibetan pigs. The intestinal morphology was not significantly different between grazing and house-feeding Tibetan pigs. The trypsin activity in the small intestines of DLY pigs was remarkably higher than that of Tibetan pigs, whereas the amylase activity in the small intestines of DLY pigs was noticeably lower than that of Tibetan pigs. The dominant phyla in all three groups were Proteobacteria, Firmicutes and Bacteroidetes. The dominant genera in Tibetan pigs were Ralstonia and Escherichia, whereas the dominant genera in DLY pigs were Ralstonia and Bradyrhizobium, but the contents were significantly different. The similarity of the intestinal bacterial community structure between house-feeding and grazing Tibetan pigs was higher than that between Tibetan and DLY pigs. [Conclusion] Significant differences in intestinal morphology, digestive enzyme activity and intestinal microbial structure were observed among grazing Tibetan, house-feeding Tibetan and DLY pigs.