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Background: Early weaning-induced stress impairs the intestinal barrier function and adversely affects the health of piglet. Probiotics can be used to prevent and treat various intestinal diseases. Lactobacillus rhamnosus GG (LGG) has an LuxS/AI-2 quorum sensing (QS) system that senses environmental changes through chemical signaling molecules. The aim of the study was to explore whether luxS mutant affects the protective role of LGG in the gut barrier of weaned piglets by comparing the luxS mutant (ΔluxS) with its wild-type (WT)., Methods: Newborn piglets were orally administered with WT and ΔluxS at dosage of 10 9 CFU, respectively. Accordingly, newborn piglets in the Con group were orally administered with PBS. Piglets were weaned on day 21 and euthanized on day 24, three days following weaning., Results: Supplementation of ΔluxS in advance significantly boosted the relative abundances of healthy microbes (including Catenibacterium , Eubacterium , Lachnospiraceae and Bifidobacterium ). WT and ΔluxS maintain intestinal barrier function mainly by promoting intestinal villus to crypt ratio (VCR), occludin protein expression and mucus secretion ( P <0.05). Furthermore, LGG reduces pro-inflammatory mediators by inhibiting TLR4 and MAPK signal transduction ( P <0.05)., Conclusion: Both WT and ΔluxS were shown to resist weaning stress by enhancing the intestinal barrier function of piglets. It has to be said that the ability of ΔluxS to maintain intestinal tissue morphology and promote mucus secretion significantly decreased compared with that of WT., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Deng, Dai, Wei, Ma, Mao, Zhang, Hua and Wang.)

Wild pigs usually showed high tolerance and resistance to several diseases in the wild environment, suggesting that the gut bacteria of wild pigs could be a good source for discovering potential probiotic strains. In our study, wild pig feces were sequenced and showed a higher relative abundance of the genus Lactobacillus (43.61% vs. 2.01%) than that in the domestic pig. A total of 11 lactic acid bacteria (LAB) strains including two L. rhamnosus , six L. mucosae , one L. fermentum , one L. delbrueckii , and one Enterococcus faecalis species were isolated. To investigate the synergistic effects of mixed probiotics strains, the mixture of 11 LAB strains from an intestinal ecology system was orally administrated in mice for 3 weeks, then the mice were challenged with Escherichia coli ATCC 25922 (2 × 10 9 CFU) and euthanized after challenge. Mice administrated with LAB strains showed higher ( p < 0.05) LAB counts in feces and ileum. Moreover, alterations of specific bacterial genera occurred, including the higher ( p < 0.05) relative abundance of Butyricicoccus and Clostridium IV and the lower ( p < 0.05) abundance of Enterorhabdus in mice fed with mixed LAB strains. Mice challenged with Escherichia coli showed vacuolization of the liver, lower GSH in serum, and lower villus to the crypt proportion and Claudin-3 level in the gut. In contrast, administration of mixed LAB strains attenuated inflammation of the liver and gut, especially the lowered IL-6 and IL-1β levels ( p < 0.05) in the gut. Our study highlighted the importance of gut bacterial diversity and the immunomodulation effects of LAB strains mixture from wild pig in gut health., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Zhong, Fu, Deng, Tang, Mao, Zhu, Zhang, Liu and Wang.)

The intestinal tract of animals is a complex ecosystem in which nutrients, microbiota and host cells interact extensively. Probiotics can be considered as part of the natural microbiota of the gut and are involved in improving homeostasis. Lactic acid bacteria (LAB) is a general term for a class of non-spore forming, gram-positive bacteria whose main product of fermented sugar is lactic acid. LAB are considered to be a type of probiotic due to their health-promoting effects on the host, and are very effective in the treatment of human and animal diseases. LAB have been widely used as a class of microbial agents in the field of livestock and poultry breeding. They are also considered to be the best substitutes for antibiotics to improve animal health. Here, we review the biological functions, probiotic characteristics and applications of LAB in livestock and poultry breeding. This review is designed to provide a theoretical base for the in-depth exploration and promotion of LAB use in animal diets., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The ability to adhere to the intestinal mucus layer is an important property of probiotic bacteria. Lactobacillus reuteri strains ZJ615 and ZJ617 show low and high adhesion, respectively, to intestinal epithelial cells. In this study, we quantified bacterial cell wall-associated glyceraldehyde-3-phosphate dehydrogenases (cw-GAPDH) and bacterial cell membrane permeability in both strains using immunoblotting and flow cytometry, respectively. Highly adhesive L. reuteri ZJ617 possessed significantly more cw-GAPDH, higher cell membrane permeability, and significantly higher adhesive ability toward mucin compared with low-adhesive L. reuteri ZJ615. In vitro adhesion studies and analysis of interaction kinetics using the Octet, the system revealed significantly decreased interaction between L. reuteri and mucin when mucin was oxidized when bacterial surface proteins were removed when bacteria were heat-inactivated at 80 °C for 30 min, and when the interaction was blocked with an anti-GAPDH antibody. SWISS-MODEL analysis suggested intensive interactions between mucin glycans (GalNAcα1-O-Ser, GalNAcαSer, and Galβ3GalNAc) and GAPDH. Furthermore, in vivo studies revealed significantly higher numbers of bacteria adhering to the jejunum, ileum, and colon of piglets orally inoculated with L. reuteri ZJ617 compared with those inoculated with L. reuteri ZJ615; this led to a significantly decreased rate of diarrhea in piglets inoculated with L. reuteri ZJ617. In conclusion, there are strong correlations among the abundance of cw-GAPDH in L. reuteri , the ability of the bacterium to adhere to the host, and the health benefits of this probiotic.

The intestine is a particularly dynamic environment in which the host constantly interacts with trillions of symbiotic bacteria called the microbiota. Using quorum sensing (QS) communication, bacteria can coordinate their social behavior and influence host cell activities in a non-invasive manner. Nowadays, a large amount of research has greatly spurred the understanding of how bacterial QS communication regulates bacterial cooperative behaviors due to coexistence and host-microbe interactions. In this review, we discuss bacterial QS in the gut and its role in biofilm formation. As a biological barrier, the mucosal immune system can effectively prevent pathogenic microorganisms and other immunogenic components from entering the internal environment of the host. We focus on the relationship between biofilm and intestinal mucosal immunity, and how probiotic bacteria may regulate them. This review is to provide a theoretical basis for the development of new techniques including probiotics targeting the intestinal barrier function, thereby improving gut health., (Copyright © 2020 Deng, Luo, Liu and Wang.)

Gut homeostasis is of importance to host health and imbalance of the gut usually leads to disorders or diseases for both human and animal. Postbiotics have been applied in manipulating of gut health, and utilization of postbiotics threads new lights into the host health. Compared with the application of probiotics, the characteristics such as stability and safety of postbiotics make it a potential alternative to probiotics. Studies have reported the beneficial effects of components derived from postbiotics, mainly through the mechanisms including inhibition of pathogens, strengthen gut barrier, and/or regulation of immunity of the host. In this review, we summarized the characteristics of postbiotics, main compounds of postbiotics, potential mechanisms in gut health, and their application in animal production. [ABSTRACT FROM AUTHOR]