Oral administration of Lactobacillus delbrueckii enhances intestinal immunity through inducing dendritic cell activation in suckling piglets

Enhancing Growth and Gut Health in Squabs: The Impact of Fermented Mixed Feed

The purpose of this study was to evaluate the effect of fermented mixed feed (FMF) (soybean meal-rapeseed meal-corn bran (6:3:1, m/m/m)) on the growth performance, intestinal microbial communities, and metabolomes of squabs. One hundred and eighty 1-day-old squabs were randomly allocated to two groups, each containing six replicates of fifteen squabs cared for by 60 pairs of breeding pigeons secreting crop milk. Each pair of breeding pigeons cared for three squabs. The control group was fed a basal diet, while the experimental group was fed the basal diet containing 5% FMF. The results showed that daily weight gain, carcass weight, villus height, and the mRNA level of ZO-1 in the ileum were increased in the birds fed FMF compared to the control squabs (p < 0.05). Greater abundances of beneficial bacteria such as Lactobacillus, Bifidobacteria, and Bacillus as well as fewer harmful bacteria (i.e., Enterococcus, Veillonella, and Corynebacterium) in the ilea of squabs fed FMF. Six differential metabolites were identified in the FMF-treated squabs; one metabolite was increased (ω-salicoyisalicin) and five were decreased (3-benzoyloxy-6-oxo-12-ursen-28-oic acid, estradiol-17-phenylpropionate, aminotriazole, phosphatidyl ethanolamine (22:6/0:0), and 1-arachidonoylglycerophosphoinositol). Positive correlations were observed between the abundance of Lactobacillus and villus height. Overall, FMF treatment improved both growth and intestinal health in pigeons, suggesting potential benefits for pigeon production.

Dietary Lactobacillus delbrueckii Affects Ileal Bacterial Composition and Circadian Rhythms in Pigs

Intestinal bacteria, synchronized with diet and feeding time, exhibit circadian rhythms and anticipate host gut function; however the effect of dietary probiotics on gut bacterial diurnal rhythms remains obscure. In this study, bacteria were sequenced at 6 Zeitgeber times (ZT) from a pig model of ileal T-shaped fistula to test ileal bacterial composition and circadian rhythms after Lactobacillus delbrueckii administration. The results showed that dietary L. delbrueckii enhanced ileal bacterial α-diversity at Zeitgeber time (ZT) 16, evidenced by an increased Simpson index compared with control pigs. At the phylum level, Firmicutes was identified as the largest phyla represented in pigs, but dietary L. delbrueckii only increased the abundance of Tenericutes at ZT16. At the genus level, 11/100 genera (i.e., Lactobacillus, Enterococcus, Leptotrichia, Pediococcus, Bifidobacte, Cellulosilyticum, Desulfomicrobium, Sharpea, Eubacterium, Propionivibrio, and Aerococcus) were markedly differentiated in L. delbrueckii-fed pigs and the effect was rhythmicity-dependent. Meanwhile, dietary L. delbrueckii affected six pathways of bacterial functions, such as membrane transport, metabolism of cofactors and vitamins, cell motility, the endocrine system, signaling molecules and interaction, and the nervous system. Cosinor analysis was conducted to test bacterial circadian rhythm in pigs, while no significant circadian rhythm in bacterial α-diversity and phyla composition was observed. Lactobacillus, Terrisporobacter, and Weissella exhibited significant rhythmic fluctuation in the control pigs, which was disturbed by probiotic exposure. In addition, dietary L. delbrueckii affected circadian rhythms in ileal Romboutsia, Erysipelatoclostridium, Cellulosilyticum, and Eubacterium abundances. Dietary L. delbrueckii affected both ileal bacterial composition and circadian rhythms, which might further regulate gut function and host metabolism in pigs.

Fecal microbiota transplantation regulates the microbiota-gut-spinal cord axis to promote recovery after spinal cord injury

Spinal cord injury (SCI) is devastating for patients, and currently lacks effective treatments. Dysbiosis commonly occurs after SCI and has significant immunomodulatory effects, but its impact on recovery remains unclear. The current study investigated the effects and mechanisms of fecal microbiota transplantation (FMT) in SCI. FMT was administered in a rat model of SCI and spinal pathology, inflammatory cytokines, and gut microbiome composition were assessed. Flow cytometry identified a source of interleukin (IL)-17 in spinal cord tissues, and carboxyfluorescein succimidyl ester labeling tracked γδ T cell migration. In vitro coculture was used to analyze the regulatory mechanisms of γδ T cells. Seahorse analysis was used to profile dendritic cell (DC) metabolism. Here we show that FMT improved spinal pathology and dampened post-injury inflammation. It also corrected post-SCI dysbiosis, increasing levels of the beneficial bacterium Akkermansia. The therapeutic effects of FMT were mediated by IL-17 produced by γδ T cells. FMT regulated γδ T cells via DC-T regulatory cell interaction, and induced metabolic reprogramming in DCs. These findings suggest that FMT represents a promising therapeutic approach for SCI, with potential to target IL-17+ γδ T cells. Elucidating the interconnected pathways between microbiota, immunity, and the spinal cord may facilitate novel treatment strategies.

Probiotics for the treatment of ulcerative colitis: a review of experimental research from 2018 to 2022

Ulcerative colitis (UC) has become a worldwide public health problem, and the prevalence of the disease among children has been increasing. The pathogenesis of UC has not been elucidated, but dysbiosis of the gut microbiota is considered the main cause of chronic intestinal inflammation. This review focuses on the therapeutic effects of probiotics on UC and the potential mechanisms involved. In animal studies, probiotics have been shown to alleviate symptoms of UC, including weight loss, diarrhea, blood in the stool, and a shortened colon length, while also restoring intestinal microecological homeostasis, improving gut barrier function, modulating the intestinal immune response, and attenuating intestinal inflammation, thereby providing theoretical support for the development of probiotic-based microbial products as an adjunctive therapy for UC. However, the efficacy of probiotics is influenced by factors such as the bacterial strain, dose, and form. Hence, the mechanisms of action need to be investigated further. Relevant clinical trials are currently lacking, so the extension of animal experimental findings to clinical application requires a longer period of consideration for validation.

Lactic Acid Bacteria as Mucosal Immunity Enhancers and Antivirals through Oral Delivery

Mucosal vaccination offer an advantage over systemic inoculation from the immunological viewpoint. The development of an efficient vaccine is now a priority for emerging diseases such as COVID-19, that was declared a pandemic in 2020 and caused millions of deaths globally. Lactic acid bacteria (LAB) especially Lactobacillus are the vital microbiota of the gut, which is observed as having valuable effects on animals’ and human health. LAB produce lactic acid as the major by-product of carbohydrate degradation and play a significant role in innate immunity enhancement. LAB have significant characteristics to mimic pathogen infections and intrinsically possess adjuvant properties to enhance mucosal immunity. Increasing demand and deliberations are being substantially focused on probiotic organisms that can enhance mucosal immunity against viral diseases. LAB can also strengthen their host’s antiviral defense system by producing antiviral peptides, and releasing metabolites that prevent viral infections and adhesion to mucosal surfaces. From the perspectives of “one health” and the use of probiotics, conventional belief has opened up a new horizon on the use of LAB as antivirals. The major interest of this review is to depict the beneficial use of LAB as antivirals and mucosal immunity enhancers against viral diseases.

Effect of the Microbiome on Intestinal Innate Immune Development in Early Life and the Potential Strategy of Early Intervention

Early life is a vital period for mammals to be colonized with the microbiome, which profoundly influences the development of the intestinal immune function. For neonates to resist pathogen infection and avoid gastrointestinal illness, the intestinal innate immune system is critical. Thus, this review summarizes the development of the intestinal microbiome and the intestinal innate immune barrier, including the intestinal epithelium and immune cells from the fetal to the weaning period. Moreover, the impact of the intestinal microbiome on innate immune development and the two main way of early-life intervention including probiotics and fecal microbiota transplantation (FMT) also are discussed in this review. We hope to highlight the crosstalk between early microbial colonization and intestinal innate immunity development and offer some information for early intervention.