Preparation of novel trivalent vaccine against enterotoxigenic Escherichia coli for preventing newborn piglet diarrhea.

OBJECTIVE: To develop a trivalent genetically engineered inactivated Escherichia coli vaccine (K88ac-3STa-LTB) that neutralizes the STa toxin by targeting fimbriae and entertoxins for the treatment of enterotoxigenic E coli. ANIMALS: 18- to 22-g mice, rabbits, pregnant sows. PROCEDURES: Using PCR, the K88ac gene and LTB gene were cloned separately from the template C83902 plasmid. At the same time, the 3 STa mutant genes were also amplified by using the gene-directed mutation technology. Immune protection experiments were performed, and the minimum immune dose was determined in mice and pregnant sows. RESULTS: The ELISA test could be recognized by the STa, LTB, and K88ac antibodies. Intragastric administration in the suckling mouse confirmed that the protein had lost the toxicity of the natural STa enterotoxin. The results of the immune experiments showed that K88ac-3STa-LTB protein could stimulate rabbits to produce serum antibodies and neutralize the toxicity of natural STa enterotoxin. The efficacy test of the K88ac-3STa-LTB-inactivated vaccine showed that the immune protection rate of the newborn piglets could reach 85% on the first day after suckling. At the same time, it was determined that the minimum immunization doses for mice and pregnant sows were 0.2 and 2.5 mL, respectively. CLINICAL RELEVANCE: This research indicates that the K88ac-3STa-LTB trivalent genetically engineered inactivated vaccine provides a broad immune spectrum for E coli diarrhea in newborn piglets and prepares a new genetically engineered vaccine candidate strain for prevention of E coli diarrhea in piglets.

Capsaicin modulates Akkermansia muciniphila abundance by enhancing MUCIN2 levels in mice fed with high-fat diets.

Extensive research has been conducted to investigate the impact of capsaicin (CAP) on lipid metabolism, focusing specifically on its interaction with the vanilloid subtype 1 (TRPV1) ion channel. Additionally, studies have illuminated the role of Akkermansia muciniphila (A. muciniphila), a specific strain of intestinal microbiota, in lipid metabolism. In this study, a model utilizing resiniferatoxin (RTX) was employed to deactivate TRPV1 ion channels in germ-free mice, followed by the administration of A. muciniphila via gavage. Following the collection of intestinal tissues for a comprehensive analysis, employing histopathology, qPCR, and ELISA techniques, our findings revealed a significant upregulation of MUC2 and MUC3 expression induced by CAP. This upregulation resulted in the thickening of the colonic mucus layers. Notably, this effect was absent when TRPV1 was selectively inhibited. Moreover, there was no discernible impact on goblet cells. The findings strongly indicate that CAP influences the system by activating the TRPV1 ion channel, thereby enhancing the expression of mucin MUC2 and promoting an augmentation in the thickness of the mucous layer. This activation, in turn, supplies A. muciniphila with an ample source of carbon and nitrogen. This insight potentially clarify the underlying mechanism through which CAP facilitates the increase in A. muciniphila abundance.