猪色氨酸形成粪臭素过程中枯草芽孢杆菌的菌群调控机理

Livestock pollution has become a widespread concern. As an essential kind of amino acid, tryptophan can increase the growth performance of pigs, but is converted into skatole under the action of large intestine bacteria. The later not only pollutes the environment, reduces the meat, further leads to diseases. The study will futrher investigate the regulation mechanism of the Bacillus subtilis on skatole bacteria in the rectum on the base of the later national natural science foundation. First study is the interaction of Bacillus subtilis and L-tryptophan in diet, deuterium labeled tryptophan, indole acetic acid and other intermediate products in fecal liquid on skatole and bacteria to explore the regulation mechanism of bacteria from the point of skatole products. Second study is the interaction of Bacillus subtilis in the fecal fluid and probiotics or harmful bacteria, Bacillus subtilis and the induction signals or signal induction quenching enzymes on skatole bacteria and qurorum sensing to explore the regulation mechanism of bacteria from the perspective of the bacteria changed. Third study is the interaction of Bacillus subtilis and probiotic and induction signal quenching enzyme in tryptophan-balance diet on pig growth and skatole bacteria and qurorum sensing from the angle of metabolic pathways of rectal bacteria. With quorum sensing as the breakthrough point, final study is to clarify the regulation mechanism of Bacillus subtilis on skatole bacteria through the intrinsic relation between the related senseing-signal genes and skatole products and bacteria changes in the above three aspects. The research will provide support for the theoretical innovation of bacteria regulation and bacteria-host interaction and for pig production and skatole reduction.

养殖污染成为普遍关注的问题。色氨酸作为一种必需氨基酸，可以提高猪的生产性能，但在大肠菌群的作用下形成粪臭素，后者不但污染环境，降低肉质,还会导致疾病的发生。在上一个国家自然基金基础上，本课题继续试验，研究枯草芽孢杆菌与日粮L-色氨酸、粪液氘标记色氨酸、吲哚乙酸等形成粪臭素过程中的不同产物对粪臭素、菌群的交互作用，从产物影响角度探讨菌群的调控机理。研究粪液中枯草芽孢杆菌与肠道有益菌和有害菌，与外源菌群感应信号和信号淬灭酶对粪臭素、菌群的交互作用，从菌群改变角度探讨菌群调控机理。研究色氨酸平衡日粮中枯草芽孢菌与肠道有益菌和信号淬灭酶对猪生产性能、粪臭素、菌群的交互作用，从菌群代谢通路角度探讨菌群调控机理。基于以上研究，以菌群感应为突破点，探究菌群感应相关基因与粪臭素产物及菌群变化之间的内在联系，深入枯草芽孢杆菌对直肠菌群的调控机理，为菌群调控、菌群-宿主互作等理论创新及促生产、减污染提供支持。

养殖污染成为普遍关注的问题。色氨酸作为一种必需氨基酸，可以提高猪的生产性能，但在大肠菌群的作用下形成粪臭素，后者不但污染环境，降低肉质,还会导致疾病的发生。本课题从色氨酸代谢产物、肠道菌群、菌群代谢通路等角度研究猪色氨酸形成粪臭素过程中枯草芽孢杆菌的菌群调控机理。试验发现枯草芽孢杆菌作用于猪粪液中色氨酸形成粪臭素过程中吲哚乙酸转化为粪臭素阶段的菌群, 改变该菌群的多样性，降低感应分子的浓度以及粪臭素的浓度。枯草芽孢杆菌对菌群AiiA、LuxS及LuxR等基因以及对对氧磷酶、酰基转移酶等淬灭酶、C8-HSL与C10-HSL等感应分子的作用受外源大肠杆菌、氧氟沙星、果聚糖等物质的影响。改变饲料中的组分，可以减少粪中群体感应分子的种类和浓度。枯草芽孢杆菌降低粪臭素后肠粘膜上的芳香羟受体含量也发生改变。本发现有助于肠道菌群调控、菌群-宿主互作等的理论创新及减抗替抗、环保养殖等产业的发展。