| The microbiota resident in the GIT and the intestinal mucosa jointly promote the development of the host immune system.Symbiotic microorganisms affect the disease resistance of host animals by competing with receptors and intestinal nutrients,producing antibacterial substances,creating microenvironments,and stimulating the innate immune system.The emergence of dominant components of the microbiota during competitive colonisation is thought to be a potential driver of the evolution of the host immune system.Lactobacillus is one of the dominant components,and their co-evolution with the host provides a good basis for promoting host health.Due to the diversity and complexity of the genus Lactobacillus,it is necessary to demonstrate which Lactobacillus strains are the most important and key players in the host GIT system in order to further describe their interactions with the host and explore the possibility of using different sources of Lactobacillus for the treatment and prevention of host intestinal diseases.This study was based on a microbiomic analysis of the abundance of Lactobacillus in the piglet gut under different conditions and typing to the genus Lactobacillus.The effects of feed additives,varieties,health status and regional factors on different Lactobacillus species,average relative abundance and strain persistence in piglet intestines were measured respectively.The results show that the main Lactobacillus species in the intestine of piglets are basically the same,and the order of average relative abundance from high to low is basically the same.Lactobacillus helveticus >Lactobacillus vaginalis > Lactobacillus delbrueckii > Lactobacillus mucosae > Lactobacillus reuteri >Lactobacillus johnsonii > Lactobacillus hamsteri > Lactobacillus salivarius > Lactobacillus pontis.The abundance of Lactobacillus helveticus and Lactobacillus vaginalis was high(P < 0.01).The abundance of Lactobacillus helveticus in diarrhea piglets decreased first and then increased.It can regulate the supply itself,and it can be restored to the control group after treatment.The abundance of Lactobacillus vaginalis decreased in the diarrhea state and increased after treatment.The abundance of Lactobacillus reuteri increased significantly in the diarrhea group and the diarrhea treatment group compared to the control group,and the production of antibacterial substances was beneficial to remove intestinal pathogens and maintain intestinal health.It was preliminarily determined that Lactobacillus helveticus and Lactobacillus vaginalis were persistent strains in the intestine of piglets,and that Lactobacillus helveticus had a better self-adjusting performance than Lactobacillus vaginalis.Based on the above results,isolate and identify the target strain,a total of 34 clinical isolates of Lactobacillus from pigs were isolated and identified.The resistance of the isolated strains to bile salt and low p H,the antibacterial power and the adhesion ability to epithelial cells in vitro were evaluated.Lactobacillus reuteri LJ-E6 showed 70.00% tolerance to the simulated gastrointestinal tract and 51.16% adherence to porcine intestinal epithelial cells(IPEC-J2).In vitro antibacterial effect of the supernatant of Lactobacillus showed that Lactobacillus vaginalis had the strongest antibacterial activity,and the supernatant of Lactobacillus vaginalis G1903(p H6.0)had an antibacterial effect on Clostridium perfringens.Combined with the intestinal fluorescence imaging experiment in mice,Lactobacillus reuteri LJ-E6 and Lactobacillus vaginalis G1903 could colonize in vivo for more than 12 h.These two strains were selected as feed additives to study the feeding effect of piglets.piglets were fed a basic diet without any antibiotics or probiotics.In the piglet feeding experiment,weaned piglets were divided into control group,Lactobacillus reuteri group and Lactobacillus vaginalis group.In the control group,piglets were fed a basal diet without any antibiotics or probiotics.The Lactobacillus reuteri and Lactobacillus vaginalis groups added Lactobacillus reuteri LJ-E6 and Lactobacillus vaginalis G1903 to the basal diet respectively.The growth performance,diarrhea rate,immune factors and intestinal flora of each group of piglets were measured and analyzed after 28 days of weaned piglets.It was found that the feeding of Lactobacillus could improve the growth performance of piglets,optimize the structure of intestinal flora,and reduce the abundance of Shigella,Clostridium,Bacteroide and Streptococcus;it improves the abundance of beneficial bacteria such as Lactobacillus and Prevotella in the gut.In summary,this study confirmed that Lactobacillus reuteri LJ-E6 and Lactobacillus vaginalis G1903 can be persistently colonise the intestinal tract of piglets.Adding pig-derived Lactobacillus to the diet can improve the growth performance of piglets and optimize the intestinal flora of healthy piglets.These two Lactobacillus can be used as feed additives to regulate the intestinal flora of piglets and prevent intestinal diseases in piglets at the early stage of weaning. |
PDF Full Text Request