Lactic acid bacteria reduce bacterial diarrhea in rabbits via enhancing immune function and restoring intestinal microbiota homeostasis

BACKGROUND

Numerous previous reports have demonstrated the efficacy of Lactic acid bacteria (LAB) in promoting growth and preventing disease in animals. In this study, Enterococcus faecium ZJUIDS-R1 and Ligilactobaciiius animalis ZJUIDS-R2 were isolated from the feces of healthy rabbits, and both strains showed good probiotic properties in vitro. Two strains (108CFU/ml/kg/day) were fed to weaned rabbits for 21 days, after which specific bacterial infection was induced to investigate the effects of the strains on bacterial diarrhea in the rabbits.

RESULTS

Our data showed that Enterococcus faecium ZJUIDS-R1 and Ligilactobaciiius animalis ZJUIDS-R2 interventions reduced the incidence of diarrhea and systemic inflammatory response, alleviated intestinal damage and increased antibody levels in animals. In addition, Enterococcus faecium ZJUIDS-R1 restored the flora abundance of Ruminococcaceae1. Ligilactobaciiius animalis ZJUIDS-R2 up-regulated the flora abundance of Adlercreutzia and Candidatus Saccharimonas. Both down-regulated the flora abundance of Shuttleworthia and Barnesiella to restore intestinal flora balance, thereby increasing intestinal short-chain fatty acid content.

CONCLUSIONS

These findings suggest that Enterococcus faecium ZJUIDS-R1 and Ligilactobaciiius animalis ZJUIDS-R2 were able to improve intestinal immunity, produce organic acids and regulate the balance of intestinal flora to enhance disease resistance and alleviate diarrhea-related diseases in weanling rabbits.

Prebiotics Inulin Metabolism by Lactic Acid Bacteria From Young Rabbits

Inulin as a commercial prebiotic could selectively promote the growth of beneficial gut microbes such as lactic acid bacteria (LAB). Whether LAB in rabbit gut possesses the capability to metabolize and utilize inulin is little known. Therefore, this study recovered 94 LAB strains from neonate rabbits and found that only 29% (28/94) could metabolize inulin with both species- and strain-specificity. The most vigorous inulin-degrading strain, Lacticaseibacillus paracasei YT170, could efficiently utilize both short-chain and long-chain components through thin-layer chromatography analysis. From genomic analysis, a predicted fosRABCDXE operon encoding putative cell wall-anchored fructan β-fructosidase, five fructose-transporting proteins and a pts1BCA operon encoding putative β-fructofuranosidase and sucrose-specific IIBCA components were linked to long-chain and short-chain inulin utilization respectively. This study provides a mechanistic rationale for effect of inulin administration on rabbits and lays a foundation for synbiotic applications aimed at modulating the intestinal microbiota of young rabbits.

The Potential of Probiotics to Eradicate Gut Carriage of Pathogenic or Antimicrobial-Resistant Enterobacterales

Probiotic supplements have been used to decrease the gut carriage of antimicrobial-resistant Enterobacterales through changes in the microbiota and metabolomes, nutrition competition, and the secretion of antimicrobial proteins. Many probiotics have shown Enterobacterales-inhibiting effects ex vivo and in vivo. In livestock, probiotics have been widely used to eradicate colon or environmental antimicrobial-resistant Enterobacterales colonization with promising efficacy for many years by oral supplementation, in ovo use, or as environmental disinfectants. In humans, probiotics have been used as oral supplements for infants to decease potential gut pathogenic Enterobacterales, and probiotic mixtures, especially, have exhibited positive results. In contrast to the beneficial effects in infants, for adults, probiotic supplements might decrease potentially pathogenic Enterobacterales, but they fail to completely eradicate them in the gut. However, there are several ways to improve the effects of probiotics, including the discovery of probiotics with gut-protection ability and antimicrobial effects, the modification of delivery methods, and the discovery of engineered probiotics. The search for multifunctional probiotics and synbiotics could render the eradication of “bad” Enterobacterales in the human gut via probiotic administration achievable in the future.

Harnessing the potential of Lactobacillus species for therapeutic delivery at the lumenal-mucosal interface

Lactobacillus species have been studied for over 30 years in their role as commensal organisms in the human gut. Recently there has been a surge of interest in their abilities to natively and recombinantly stimulate immune activities, and studies have identified strains and novel molecules that convey particular advantages for applications as both immune adjuvants and immunomodulators. In this review, we discuss the recent advances in Lactobacillus-related activity at the gut/microbiota interface, the efforts to probe the boundaries of the direct and indirect therapeutic potential of these bacteria, and highlight the continued interest in harnessing the native capacity for the production of biogenic compounds shown to influence nervous system activity. Taken together, these aspects underscore Lactobacillus species as versatile therapeutic delivery vehicles capable of effector production at the lumenal-mucosal interface, and further establish a foundation of efficacy upon which future engineered strains can expand.

Bacillus strains improve growth performance via enhancing digestive function and anti-disease ability in young and weaning rex rabbits

Numerous studies have shown that probiotic Bacillus could promote growth and enhance anti-disease ability in animal. In present study, the mixture of three Bacillus strains, which were isolated from rex rabbits and showed high cellulose, protease, and amylase activities, was added into the diet for investigating its effects on young and weaning rex rabbits. For experiment 1, 40 young rex rabbits (9 weeks old) were randomly divided into four groups and fed with diets containing 0 (NC), 1.0 × 10⁵ cfu/g (LC), 1.0 × 10⁶ cfu/g (MC), and 1.0 × 10⁷ cfu/g (HC) Bacillus strains for 4 weeks. For experiment 2, 80 weaning rex rabbits (5 weeks old) were randomly divided into four groups and fed with diet containing 0 (control), 1.0 × 10⁵ cfu/g (T-1), 1.0 × 10⁶ cfu/g (T-2), and 1.0 × 10⁷ cfu/g (T-3) Bacillus strains for 8 weeks. The results showed that Bacillus strains at a dose of 1.0 × 10⁶ cfu/g significantly enhanced growth performance, increased immune organ indexes, improved serum biochemical parameters, and heightened antioxidant capacity. It also markedly improved the intestinal microbiota by increasing Lactobacillus spp., Bacillus spp. counts, and decreased Escherichia coli count. In addition, the Bacillus mixture raised the concentrations of acetic acid, propionic acid, and butyric acid as well as protease, amylase, and cellulase activities of young and weaning rex rabbits. Moreover, for weaning rex rabbits, the inclusion of Bacillus strains also upregulated the abundance of cellulolytic bacteria and improved intestinal morphology. Therefore, our results indicated that Bacillus strains could facilitate the growth of young and weaning rex rabbits by improving digestive function and anti-disease ability. KEY POINTS: • Bacillus with high extracellular enzyme activity were isolated from rex rabbits. • Bacillus could improve growth performance of young and weaning rex rabbits. • The digestive function of young and weaning rex rabbits could be improved by Bacillus.

Anti-Photoaging Effect of Plant Extract Fermented with Lactobacillus buchneri on CCD-986sk Fibroblasts and HaCaT Keratinocytes

Ultraviolet (UV) exposure triggers the abnormal production of reactive oxygen (ROS) species and the expression of matrix metalloproteinases (MMPs) that are responsible for photoaging. Probiotics are widely used in healthcare and for immune enhancement. One probiotic, Lactobacillus buchneri is found in Kimchi. This study was aimed at assessing the anti-photoaging effect of plant extracts fermented with L. buchneri (PELB) to develop functional cosmetics. We investigated the anti-photoaging effect of PELB in a UVB-induced photoaging in vitro model and selected effective extracts using the elastase inhibition assay, ELISA for Type I procollagen and collagenase-1, and quantitative real time PCR. Normal human dermal fibroblasts and epidermal keratinocytes were pre-treated with PELB and exposed to UVB. We found that PELB decreased elastase activity and increased type I collagen expression in a UVB-induced photoaging in vitro model. In addition, PELB greatly reduced collagenase activity and MMP mRNA levels in a UVB-induced photoaging in vitro model. Furthermore, PELB promoted the expression of moisture factor and anti-oxidant enzymes in a UVB-induced photoaging in vitro model. These results indicated that the PELB could be potential candidates for the protective effects against UVB-induced photoaging. Overall, these results suggest that PELB might be useful natural components of cosmetic products.

Faecal microbiota and functional capacity associated with weaning weight in meat rabbits

Weaning weight is an important economic trait in the meat rabbit industry. Evidence has linked the gut microbiota to health and production performance in rabbits. However, the effect of gut microbiota on meat rabbit weaning weight remains unclear. In this study, we performed 16S rRNA gene sequencing analysis of 135 faecal samples from commercial Ira rabbits. We detected 50 OTUs significantly associated with weaning weight. OTUs that showed positive associations with weaning weight were mostly members of the family Ruminococcaceae which are important in degrading dietary fibres and producing butyrate. On the contrary, OTUs annotated to genera Blautia, Lachnoclostridium and Butyricicoccus correlated with fat deposition were negatively associated with weaning weight. Predicted functional capacity analysis revealed that 91 KOs and 26 KEGG pathways exhibited potential correlations with weaning weight. We found that gut microbiota involved in the metabolism of amino acids, butanoate, energy and monosaccharides affected weaning weight. Additionally, cross-validation analysis indicated that 16.16% of the variation in weaning weight was explained by the gut microbiome. Our findings provide important information to improve weaning weight of meat rabbits by modulating their gut microbiome.

A meta-analysis of the effects of probiotics and synbiotics in children with acute diarrhea

OBJECTIVE

This meta-analysis assessed the effectiveness of probiotics and synbiotics for acute diarrhea (AD) in children and investigated probiotic formulations, types of interventions, and country factors.

METHODS

Randomized, double-blind, placebo-controlled trials evaluating the effects of probiotics or synbiotics on AD were analyzed. We followed the recommendations of the Cochrane Handbook and the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement. The risks of systematic errors (bias) and random errors were assessed, and the overall quality of the evidence was evaluated using the Grades of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

RESULTS

The meta-analysis included 34 studies with 4911 patients. Five and 29 studies presented the results of synbiotic and probiotic interventions, respectively. After intervention, the durations of diarrhea (weighted mean difference (WMD) = -16.63 [-20.16; -12.51]) and hospitalization (risk ratio (RR) = 0.59 [0.48; 0.73]) were shorter, the stool frequency on day 3 (WMD = -0.98 [-1.55; -0.40]) was decreased, and the incidence of diarrhea lasting 3 days was lower in the probiotic and synbiotic groups than in the control groups. Furthermore, in the subgroup analyses, synbiotics were more effective than probiotics at reducing the durations of diarrhea and hospitalization, and Saccharomyces and Bifidobacterium were more effective than Lactobacillus at reducing the duration of diarrhea.

CONCLUSION

This meta-analysis supports the potential beneficial roles of probiotics and synbiotics for AD in children. Further research is needed to determine problems associated with probiotic/synbiotic mixtures and appropriate dosages.