Potential of lactic acid bacteria at regulating Escherichia coli infection and inflammation of bovine endometrium

Microbial Gatekeepers of Fertility in the Female Reproductive Microbiome of Cattle

This review paper delves into the intricate relationship between the genital microbiome and fertility outcomes in livestock, with a specific focus on cattle. Drawing upon insights derived from culture-independent metagenomics studies, the paper meticulously examines the composition and dynamics of the genital microbiome. Through advanced techniques such as high-throughput sequencing, the review illuminates the temporal shifts in microbial communities and their profound implications for reproductive health. The analysis underscores the association between dysbiosis-an imbalance in microbial communities-and the development of reproductive diseases, shedding light on the pivotal role of microbial gatekeepers in livestock fertility. Furthermore, the paper emphasizes the need for continued exploration of uncharted dimensions of the female reproductive microbiome to unlock new insights into its impact on fertility. By elucidating the complex interplay between microbial communities and reproductive health, this review underscores the importance of innovative strategies aimed at enhancing fertility and mitigating reproductive diseases in livestock populations.

Pharmabiotic/phytobiotic formulas approach and their intravaginal effect on different parameters

Postpartum reproductive infections in cows generate significant economic losses. The use of lactic acid bacteria in animal health is an alternative tool to avoid antibiotic therapy in the prevention/treatment of bovine reproductive infections. In previous studies, 6 lactic bacteria from bovine mammary glands and vagina with beneficial, safe and technological characteristics were selected, and included in probiotic/phytobiotic formulas (combined with Malva and Lapacho extracts). In this work, probiotic and phytobiotic formulations were designed and their long-term viability determined. They were administered intravaginally to 30 females pregnant bovine pre and postpartum. The modification of the native microbiota and permanence/colonization of cultivable bacteria was evaluated, and also the safety of the designed products through the application of nutritional, clinical, hematological and biochemical parameters. The microorganisms maintained their viability up to 9 months at refrigeration temperature. The number of cultivable bacteria showed different pattern: total aerobic mesophylls increased slightly in all experimental groups, while Enterobacteriaceae increased after delivery, except in beneficial acid lactic bacteria + vegetable extract cows. Control and vegetable extract females showed the highest numbers of Enterobacteriaceae at the end of the trial (30 days postpartum). The number of lactic acid bacteria increased significantly in all the groups between 15 days pre and postpartum. The different parameters evaluated demonstrate the safety and harmlessness of the designed formulas, without producing local and systemic adverse effects in the cows.

Protective effects of engineered Lactobacillus johnsonii expressing bovine granulocyte-macrophage colony-stimulating factor on bovine postpartum endometritis

Introduction

Postpartum endometritis is a prevalent reproductive disorder in bovines, leading to a prolonged open period, infertility, and other complications. While Lactobacillus strains can mitigate these conditions by reducing uterine inflammation, their effectiveness is limited due to a lack of direct anti microbial action and extended treatment duration. This study aimed to construct a recombinant Lactobacillus johnsonii strain expressing bovine Granulocyte-macrophage colony-stimulating factor (GM-CSF) to evaluate its potential in reducing postpartum uterine inflammation.

Methods

The recombinant Lactobacillus johnsonii strain was engineered to express bovine GM-CSF and administered to pregnant mice via vaginal perfusion. Postpartum endometritis was induced using E. coli infection, and the protective effects of the engineered strain were assessed. Inflammatory markers (IL-6, IL-1β, TNF-α), myeloperoxidase (MPO) activity, and nitric oxide (NO) concentration were measured. Histological examination was performed to evaluate uterine morphology and pathological damage.

Results

The recombinant L. johnsonii strain expressing GM-CSF significantly reduced inflammation levels induced by E. coli infection in the uterus. This reduction was evidenced by decreased expression of IL-6, IL-1β, TNF-α, as well as reduced MPO activity and NO concentration. Histological examination revealed improved uterine morphology and reduced pathological damage in mice treated with the recombinant GM-CSF strain. Crucially, the recombinant strain also exerts beneficial effects on bovine endometritis by reducing levels of inflammatory cytokines, suggesting a beneficial effect on clinical bovine endometritis.

Conclusion

The recombinant Lactobacillus johnsonii expressing GM-CSF demonstrated protective effects against postpartum endometritis in bovines by reducing inflammatory cytokines. The findings indicate the potential clinical application of this engineered strain in preventing postpartum uterine inflammation, offering a novel and effective protective option for related disorders and improving bovine reproductive efficiency.

Population characteristics of pathogenic Escherichia coli in puerperal metritis of dairy cows in Ningxia region of China: a systemic taxa distribution of virulence factors and drug resistance genes

Escherichia coli (E. coli) is closely associated with the occurrence of puerperal metritis in dairy cows. E. coli carries some the virulence and multi-drug resistant genes, which pose a serious threat to the health of postpartum cows. In this study, E. coli was isolated and identified from the uterine contents of postpartum cows with puerperal metritis in the Ningxia region of China, and its phylogenetic subgroups were determined. Meanwhile, virulence and drug resistance genes carried by E. coli and drug sensitivity were detected, and the characteristics of virulence and drug resistance genes distribution in E. coli phylogroups were further analyzed. The results showed that the isolation rate of E. coli in puerperal metritis samples was 95.2%. E. coli was mainly divided into phylogroups B2 and D, followed by groups A and B1, and was more connected to O157:H7, O169:H4, and ECC-1470 type strains. The virulence genes were mainly dominated by ompF (100%), traT (100%), fimH (97%), papC (96%), csgA (95%), Ang43 (93.9%), and ompC (93%), and the resistance genes were dominated by TEM (99%), tetA (71.7%), aac(3)II (66.7%), and cmlA (53.5%). Additionally, it was observed that the virulence and resistance gene phenotypes could be divided into two subgroups, with subgroup B2 and D having the highest distributions. Drug sensitivity tests also revealed that the E. coli was most sensitive to the fluoroquinolones enrofloxacin, followed by macrolides, aminoglycosides, tetracyclines, β-lactams, peptides and sulfonamides, and least sensitive to lincosamides. These results imply that pathogenic E. coli, which induces puerperal metritis of dairy cows in the Ningxia region of China, primarily belongs to the group B2 and D, contains multiple virulence and drug resistance genes, Moreover, E. coli has evolved resistance to several drugs including penicillin, lincomycin, cotrimoxazole, and streptomycin. It will offer specific guidelines reference for the prevention and treatment of puerperal metritis in dairy cows with E. coli infections in the Ningxia region of China.

Harnessing Vaginal Probiotics for Enhanced Management of Uterine Disease and Reproductive Performance in Dairy Cows: A Conceptual Review

Uterine disease in cattle impairs reproductive performance and profitability and increases antibiotic use and antimicrobial resistance. Thus, probiotics offer a promising alternative therapy. This review presents conceptual findings on the efficacy of probiotics in managing uterine diseases and fertility in cows. Probiotics containing Lactobacillus spp. and Bifidobacterium spp. individually or as composite formulations are known to improve fertility. Strategic intravaginal administration of these formulations would likely enhance uterine immunity, particularly during the postpartum period. While current findings on the benefits to uterine health are encouraging, there is still significant knowledge missing, including a lack of empirical information from large-scale field trials. This review underscores the need for evidence-based guidelines for probiotics, such as genomic selection of formulations, targeted delivery, or potential synergy with other interventions. Future research should address these gaps to maximize the potential of probiotics in managing uterine diseases and enhancing the reproductive health of dairy cattle.

Invited review: "Probiotic" approaches to improving dairy production: Reassessing "magic foo-foo dust"

The gastrointestinal microbial consortium in dairy cattle is critical to determining the energetic status of the dairy cow from birth through her final lactation. The ruminant's microbial community can degrade a wide variety of feedstuffs, which can affect growth, as well as production rate and efficiency on the farm, but can also affect food safety, animal health, and environmental impacts of dairy production. Gut microbial diversity and density are powerful tools that can be harnessed to benefit both producers and consumers. The incentives in the United States to develop Alternatives to Antibiotics for use in food-animal production have been largely driven by the Veterinary Feed Directive and have led to an increased use of probiotic approaches to alter the gastrointestinal microbial community composition, resulting in improved heifer growth, milk production and efficiency, and animal health. However, the efficacy of direct-fed microbials or probiotics in dairy cattle has been highly variable due to specific microbial ecological factors within the host gut and its native microflora. Interactions (both synergistic and antagonistic) between the microbial ecosystem and the host animal physiology (including epithelial cells, immune system, hormones, enzyme activities, and epigenetics) are critical to understanding why some probiotics work but others do not. Increasing availability of next-generation sequencing approaches provides novel insights into how probiotic approaches change the microbial community composition in the gut that can potentially affect animal health (e.g., diarrhea or scours, gut integrity, foodborne pathogens), as well as animal performance (e.g., growth, reproduction, productivity) and fermentation parameters (e.g., pH, short-chain fatty acids, methane production, and microbial profiles) of cattle. However, it remains clear that all direct-fed microbials are not created equal and their efficacy remains highly variable and dependent on stage of production and farm environment. Collectively, data have demonstrated that probiotic effects are not limited to the simple mechanisms that have been traditionally hypothesized, but instead are part of a complex cascade of microbial ecological and host animal physiological effects that ultimately impact dairy production and profitability.

Uterine Disease in Dairy Cows: A Comprehensive Review Highlighting New Research Areas

Uterine disease is an intensely studied part of dairy cattle health management as it heavily affects many commercial dairy farms and has serious economic consequences. Forms of the disease, pathophysiology, pathogens involved and the effects of uterine disease on the health and performance of cows have already been well described by various authors. Lately, researchers' attention has shifted towards the healthy microbiome of the uterus and the vagina to put emphasis on prevention rather than treatment. This aligns with the growing demand to reduce the use of antibiotics or-whenever possible-replace them with alternative treatment options in farm animal medicine. This review provides a comprehensive summary of the last 20 years of uterine disease research and highlights promising new areas for future studies.

Uterine microbial ecology and disease in cattle: A review

Due to the critical contribution of the uterine-associated microbiota in reproductive health, physiology, and performance, culture-independent methods have been increasingly employed to unravel key aspects of microbial ecology in the uterus of cattle. Nowadays, we know that bacterial diversity is crucial to maintain uterine health, however, there is still no consensus on the exact composition of a healthy uterine microbiota (or eubiosis). Generally, loss of bacterial diversity (or dysbiosis) contributes to the development of uterine infections, associated with increased relative abundances of Bacteroides, Fusobacterium, Trueperella, and Porphyromonas. Uterine infections are highly prevalent and gravely influence the profitability of cattle operations, animal welfare, and public health. Thus, understanding the dynamics of uterine microbial ecology is essential to develop effective strategies focused on preventing and mitigating the adverse effects of uterine dysbiosis as well as assisting in the process of restoring the core, healthy uterine microbiota. The aim of this review is to summarize research conducted in the microbial ecology of bovine uteri. We discuss the origin of the uterine microflora of healthy cows and the factors influencing its composition. In addition, we review the biology of specific pathogens that are known to increase in abundance during the occurrence of uterine disease. Lastly, we provide an overview of the bacterial biofilm in the bovine endometrium, and we briefly summarize the rationale for the use of probiotics to prevent uterine disease in cattle.

A short-term comparison of wheat straw and poplar wood chips used as litter in tiestalls on hygiene, milk, and behavior of lactating dairy cows

A short-term study was conducted to compare the effect of using poplar wood chips (PWC) instead of wheat straw (WS) litter in dairy cows. A total of 38 lactating Holstein cows (204 ± 119 days in milk, 26.9 ± 6.5 kg of milk yield [MY]) were housed in a tiestall farm for a 10-d trial including 5 d of adaptation followed by 5 sampling days (from d 5 to 10). Cows were divided into 2 homogeneous groups: one group was bedded with WS, and the second with PWC. Both litter materials were provided in the amount of 7 kg/stall per d. Each group was composed of 3 subgroups of 6 or 7 cows; the subgroups were physically separated along the feeding line by wooden boards. During the sampling days, fecal composition, used litter composition, and bacterial count (Clostridium spp., Salmonella spp., Escherichia coli, Lactobacillus, and total bacterial count) were analyzed by subgroup twice a day. On d 1 and from d 5 to 10, udder hygiene score and cow cleanliness score were also evaluated individually twice a day. Meanwhile MY, milk hygiene (total bacterial count [TBC], coliform bacterial count [CBC], and spore-forming units [SFU]) and quality were measured and analyzed from 9 animals per group. Moreover, individual animal behavior (body position and behavioral traits) and subgroup dry matter intake were measured on d 9 and 10. Fecal dry matter did not differ between groups, PWC had the lowest used litter moisture and N content favoring the highest clean cow frequency, but also gave rise to the greatest used litter microbial contamination. The MY, milk quality, TBC, SFU, and CBC were similar. The lying behavior frequency was similar between groups. However, the PWC group showed the lowest sleeping frequency, the highest frequency of other behaviors (including discomfort signs), and the lowest dry matter intake. However, despite this apparent reduction in cow comfort, no biologically important differences were observed in this short-term study between cows on PWC and WS in milk production or hygiene.

Characterization of the follicular fluid microbiota based on culturomics and sequencing analysis

Introduction. The human oocyte microenvironment is follicular fluid, which is important for follicle growth, ovulation and maturation of the oocyte. The micro-organisms present in follicular fluid could be a predictor of in vitro fertilization outcomes.Hypothesis/Gap Statement. Women with follicular fluid colonized with micro-organisms can be asymptomatic, but the presence of some genera in the follicular fluid correlates with in vitro fertilization.Aim. To confirm the existence of micro-organisms in follicular fluid, and to profile the micro-organisms present in follicular fluid sampled from women undergoing in vitro fertilization with different outcomes.Methodology. Women undergoing in vitro fertilization (n=163) were divided into different subgroups according to their in vitro fertilization outcomes. Their follicular fluid samples were collected, and among them, 157 samples were analysed by 16S rDNA sequencing, and 19 samples were analysed using culturomics.Results. The culturomics results suggested that the 19 follicular fluid samples were not sterile. The isolation rates for Streptococcus, Finegoldia and Peptoniphilus were >50 % in the 19 samples. Linear discriminant analysis effect size analysis showed differential bacteria abundance according to the pregnancy rate, the rate of normal fertilization, the rate of high-quality embryos and the rate of available oocytes. The sequencing results showed that micro-organisms could be detected in all 157 samples. Pseudomonas, Lactobacillus, Comamonas, Streptococcus and Acinetobacter were detected in all of the samples, but with a wide range of relative abundance. Pseudomonas, Lactobacillus, Ralstonia and Vibrio constituted a notable fraction of the microbiota.Conclusions. Follicular fluid is not sterile. Micro-organisms in follicular fluid could be a predictor of in vitro fertilization outcomes.

Uterine Tissue Metabonomics Combined with 16S rRNA Gene Sequencing To Analyze the Changes of Gut Microbiota in Mice with Endometritis and the Intervention Effect of Tau Interferon

Endometritis is a common cow disease characterized by inflammation of endometrium, which leads to infertility or low fertility of cows and brings huge economic losses to the dairy industry. Tau interferon (IFN-τ) has many important biological functions, including an anti-inflammatory effect. The present study aimed to survey the effects of IFN-τ administration on gut microflora and body metabolism in mice with endometritis and to explore the potential relationship. The results indicated that IFN-τ obviously alleviated the damage and ultrastructural changes of mouse endometrium induced by Escherichia coli and enhanced tight junction protein's expression level. Through analysis by 16S rRNA gene sequencing, we found that IFN-τ, especially at 12 h, could regulate the composition of gut microbiota associated with Pediococcus, Staphylococcus, and Enterorhabdus in E. coli-induced mouse endometritis. Through histometabonomics, it was found that endometritis was related to 11 different metabolites and 4 potential metabolic pathways. These metabolites and metabolic pathways were major participants in metabolic pathways, cysteine and methionine metabolism, arachidonic acid metabolism, and pyrimidine metabolism. Correlation analysis of gut microbiota with uterine tissue metabolomics showed that changes in metabolic pathways might be affected by gut microbiota, such as Enterorhabdus in mouse endometritis. The above results indicated that the anti-inflammatory mechanism of IFN-τ might be reduction of the abundance of Enterorhabdus in the gut microbiota, affecting the expression level of important metabolites in uterine tissue and thus playing an anti-inflammatory role. IMPORTANCE The change in intestinal flora has been the focus of many disease studies in recent years, but the pathogenetic effect of interferon on endometritis is still unclear. The results of this study showed that IFN-τ alleviated the damage in mouse endometritis induced by E. coli and improved the endometrial tissue barrier. Its functional mechanism may be reduction of the abundance of Enterorhabdus in the intestinal microbiota, affecting the expression level of important metabolites in uterine tissue and thus playing an anti-inflammatory role.

Use of intravaginal lactic acid bacteria prepartum as an approach for preventing uterine disease and its association with fertility of lactating dairy cows

The objective of this study was to evaluate the effects of the use of intravaginal probiotics prepartum on the incidence risk of metritis postpartum and conception risk after first artificial insemination (AI). A total of 606 Holstein cows were enrolled 3 wk before their expected calving date from 2 farms. Cows were randomly assigned to either receive a 2-mL dose of a combination of 3 lactic acid bacteria (probiotic treatment) washed with approximately 2 mL of a sterile saline solution, into the vaginal canal twice weekly until parturition, or no intervention (control). Metritis diagnoses were carried out on 6 and 12 d postpartum. Vaginal discharge and rectal temperature were assessed, and vaginal discharge was scored on a scale from 1 to 4, where 1 = clear and 4 = fetid, purulent discharge. Metritis was defined as cows having a vaginal discharge score of 4 with or without fever (rectal temperature ≥39.5°C) on either 6 or 12 d postpartum, or both. Cows were bred after a 60-d voluntary waiting period primarily via the detection of estrus using automated activity monitors; cows not found in estrus were enrolled onto timed AI protocols to receive first breeding before 100 DIM. Pregnancy diagnosis was carried out at d 35 ± 7 post-AI on both farms. Data were analyzed via ANOVA using linear mixed regression models and survival analysis using a Cox proportional hazard model. Total incidence risk of metritis was 23.7% and 34.4% on farm A and farm B, respectively. Overall, the incidence of metritis was not different between treatment groups (control: 41.6 ± 3.8%; probiotic: 38.6 ± 4.0%); however, an interaction by farm was detected, where the probiotic treatment reduced metritis on one farm but not on the other. Conception risk after first AI was not affected by treatment. However, we detected an interaction between parity and treatment, where multiparous cows receiving the probiotic treatment were more likely to become pregnant compared with multiparous cows within the control group (hazard ratio: 1.33; 95% confidence interval: 1.10-1.60); no effect of probiotic treatment was found on the hazard of pregnancy for primiparous cows. In addition, the probiotic treatment was associated with an increased proportion of cows being detected in estrus for the first AI postpartum. In conclusion, vaginal probiotic treatment applied during the 3 wk prepartum was associated with a decreased incidence of metritis on one farm but not the other, suggesting that farm management may be a key player influencing treatment efficacy. Overall, probiotic treatment was found to have only limited effects on fertility in the current study.

Beneficial Effects of Lactic Acid Bacteria on Animal Reproduction Function

Considering the importance of a healthy uterus to the success of breeding, the beneficial effects of lactic acid bacteria on animal reproduction function are of particular interest. In recent decades, infertility has become a widespread issue, with microbiological variables playing a significant role. According to reports, dysbiosis of the vaginal microbiota is connected with infertility; however, the effect of the normal vaginal microbiota on infertility is unknown. In addition, lactic acid bacteria dominate the reproductive system. According to evidence, vaginal lactic acid bacteria play a crucial role in limiting the invasion of pathogenic bacteria by triggering anti-inflammatory chemicals through IL-8, IL-1, and IL-6; immunological responses through inhibition of the adherence of other microorganisms, production of inhibiting substances, and stimulation of mucus production; and also reproductive hormones by increased testosterone hormone release, enhanced the levels of luteinizing hormone, follicle stimulating hormone, the amount of prostaglandin E (2), and prostaglandin F2 alpha. The objective of this study was to compare the advantages of lactic acid bacteria in animal reproduction based on the most recent literature. The administration of a single strain or numerous strains of lactic acid bacteria has a favourable impact on steroidogenesis, gametogenesis, and animal fertility.

Clostridium butyricum and Its Culture Supernatant Alleviate the Escherichia coli-Induced Endometritis in Mice

Endometritis is a disease with a high incidence in dairy cows and causes great economic loss to milk production. This study examined the therapeutic effects of Clostridium butyricum and its culture supernatant on Escherichia coli-induced endometritis in mice. The results showed that Clostridium butyricum and its culture supernatant effectively suppressed inflammatory responses of uterine tissues, such as uterine morphological changes, pathological damage, and the production of inflammatory cytokines. Clostridium butyricum and its culture supernatant significantly decreased uterine microbial loads. In addition, Clostridium butyricum and its culture supernatant restored reproduction outcomes in Escherichia coli-induced endometritis mice. Western blot analysis showed that Clostridium butyricum and its culture supernatant suppressed the NF-κB signaling pathway. Therefore, the anti-inflammatory mechanism of Clostridium butyricum and its culture supernatant may occur through the anti-bacterial activity and regulation of the expression of NF-κB in the uterus. The anti-inflammatory effect of the culture supernatant of C. butyricum was slightly better than that of viable C. butyricum. Therefore, our experimental results showed that Clostridium butyricum culture supernatant may be an effective drug for treating endometritis.

Lactobacillus rhamnosus GR-1 Alleviates Escherichia coli-Induced Inflammation via NF-κB and MAPKs Signaling in Bovine Endometrial Epithelial Cells

Escherichia coli counts as a major endometritis-causing pathogen among dairy cows, which lowered the economic benefits of dairy farming seriously. Probiotic consumption has been reported to impart beneficial effects on immunomodulation. However, the inflammatory regulation mechanism of probiotics on endometritis in dairy cows remains unexplored. The current work aimed to clarify the mechanism whereby Lactobacillus rhamnosus GR-1 (L. rhamnosus GR-1) resists bovine endometrial epithelial cells (BEECs) inflammatory injury induced by E. coli. The model of cellular inflammatory injury was established in the BEECs, which comes from the uterus of healthy dairy cows using E. coli. The outcome of L. rhamnosus GR-1 addition on inflammation was evaluated in BEECs with E. coli-induced endometritis. The underlying mechanisms of anti-inflammation by L. rhamnosus GR-1 were further explored in E. coli-stimulated BEECs. In accordance with the obtained results, the use L. rhamnosus GR-1 alone could not cause the change of inflammatory factors, while L. rhamnosus GR-1 could significantly alleviate the expression of E. coli-induced inflammatory factors. Based on further study, L. rhamnosus GR-1 significantly hindered the TLR4 and MyD88 expression stimulated by E. coli. Moreover, we observed that in BEECs, L. rhamnosus GR-1 could inhibit the E. coli-elicited expressions of pathway proteins that are associated with NF-κB and MAPKs. Briefly, L. rhamnosus GR-1 can effectively protect against E. coli-induced inflammatory response that may be closely related to the inhibition of TLR4 and MyD88 stimulating NF-κB and MAPKs.

Lactobacillus rhamnosus Ameliorates Multi-Drug-Resistant Bacillus cereus-Induced Cell Damage through Inhibition of NLRP3 Inflammasomes and Apoptosis in Bovine Endometritis

Bacillus cereus, considered a worldwide human food-borne pathogen, has brought serious health risks to humans and animals and huge losses to animal husbandry. The plethora of diverse toxins and drug resistance are the focus for B. cereus. As an alternative treatment to antibiotics, probiotics can effectively alleviate the hazards of super bacteria, food safety, and antibiotic resistance. This study aimed to investigate the frequency and distribution of B. cereus in dairy cows and to evaluate the effects of Lactobacillus rhamnosus in a model of endometritis induced by multi-drug-resistant B. cereus. A strong poisonous strain with a variety of drug resistances was used to establish an endometrial epithelial cell infection model. B. cereus was shown to cause damage to the internal structure, impair the integrity of cells, and activate the inflammatory response, while L. rhamnosus could inhibit cell apoptosis and alleviate this damage. This study indicates that the B. cereus-induced activation of the NLRP3 signal pathway involves K⁺ efflux. We conclude that LGR-1 may relieve cell destruction by reducing K⁺ efflux to the extracellular caused by the perforation of the toxins secreted by B. cereus on the cell membrane surface.

Safety, environmental and technological characterization of beneficial autochthonous lactic bacteria, and their vaginal administration to pregnant cows for the design of homologous multi-strain probiotic formulas

In recent years, veterinary probiotic formulations constitute an interesting alternative to the use of antibiotics in animals for human consumption, but beneficial microorganisms must meet certain requirements to be included in these products. The objective of this work was to evaluate the safety and innocuity of beneficial autochthonous lactic bacteria (BALB) as well as to determine their beneficial, environmental, and technological characterization. Antibiotic resistance was assayed using phenotypic and genotypic methodology. A bovine vaginal fluid simulated medium (MSBVF) was designed where growth, pH changes, and expression of beneficial characteristics of lactic bacteria were evaluated; additionally, the optimal culture conditions in commercial media were determined in order to obtain the highest biomass production of the strains. Finally, the best strains were lyophilized and administered intravaginally to pregnant cows and their permanence in the vagina and adverse effects were evaluated. The results show that most of the strains were resistant to vancomycin, tetracycline, and streptomycin, with a high sensitivity to ampicillin, gentamicin, and clindamycin. The strains evaluated did not show gelatinase or hyaluronidase activity; however, 11 strains produced α-type hemolysis. The optimal growth of the microorganism was obtained in MRS broth, under slight agitation and without pH control. The strains grown in the MSBVF grew well and maintained the probiotic properties. Animals treated with probiotics bacteria did not show systemic or local inflammation. These strains can be included in a probiotic veterinary product to be applied to different bovine mucosa.

Association of intrauterine presence of Lactobacillus spp. with inflammation and pathogenic bacteria in the uterus in postpartum dairy cows

The aim of this study was to clarify the influence of Lactobacillus spp. on the degree of endometrial inflammation in the postpartum period and the relationship between Lactobacillus spp. and pathogenic bacteria in the endometrium of postpartum dairy cows. Endometrial samples were collected from 41 Holstein-Friesian cows at 4 and 8 weeks postpartum using cytobrushes for polymorphonuclear neutrophil (PMN) count and bacterial culture to isolate Lactobacillus spp., Escherichiacoli, and Trueperella pyogenes. The 4-week samples were divided into four groups (E+L+), (E+L−), (E−L+), (E−L−) according to whether endometritis was diagnosed (E+) and Lactobacillus spp. was isolated (L+). The diagnostic criterion for cytological endometritis was > 18% PMN. The average PMN% in the E+L+ group was lower than that in the E+L-group (P < 0.05) at 8 weeks postpartum. There were no significant correlations between the number of colonies of Lactobacillus spp. and E. coli or between that of Lactobacillus spp. and T. pyogenes. Lactobacillus spp. could reduce PMN% in dairy cows with endometritis during the puerperal period. In conclusion, the intrauterine presence of Lactobacillus spp. may have a positive effect on uterine involution in postpartum dairy cows.

Effect of Lactobacillus johnsonii Strain SQ0048 on the TLRs-MyD88/NF-κB Signaling Pathway in Bovine Vaginal Epithelial Cells

Vaginal inflammation is a common disease of the dairy cows' reproductive tract. Lactic acid bacteria can combat purulent inflammation caused by pathogenic bacteria and regulate the NF-κB signaling pathway mediated by toll-like receptors (TLRs) in the inflammatory response. We studied the effect of Lactobacillus johnsonii SQ0048, an isolate with antibacterial activity, on the NF-κB signaling pathway in cow vaginal epithelial cells. The expression levels of serial effectors related to the TLRs-MyD88/NF-κB signaling pathway (TLR2, TLR4, MyD88, IKK, NF-κB, IL-1β, IL-6, TNF-α, and IL-10) were measured with real-time polymerase chain reaction (RT-PCR), ELISA, and Western blot analyses. TLR2 and TLR4 were activated by SQ0048 cells, as noted by increased mRNA expression levels of TLR2 and TLR4 in SQ0048-treated bovine vaginal epithelial cells relative to control cells (P <0.01). SQ0048 treatment also significantly increased MyD88 and IKK expression, and activated NF-κB in vaginal epithelial cells (P <0.01). In addition, SQ0048 treatment also significantly increased mRNA expression levels of IL-1β, IL-6, and TNF-α, but decreased IL-10 mRNA expression levels (P <0.01). These data indicate that strain SQ0048 presence can improve the immune functions of cow vaginal epithelial cells by activating TLRs-MyD88/NF-κB signaling pathways. However, further in vivo studies are required to confirm these findings.

Reproductive Tract Infections in Dairy Cows: Can Probiotics Curb Down the Incidence Rate?

Postpartum uterine diseases are common in dairy cows and are a great concern for the dairy industry as they are associated with various consequences, including lower fertility, lower milk yield, and an overall negative impact on the host health. An infected uterus is a source of bacterial compounds and cytokines that spill into the systemic circulation, spreading inflammation to other organs. In this review article, we discuss a short overview of the anatomy of the reproductive tract of dairy cows and several infectious diseases of the uterus including metritis, endometritis, and pyometra. Additionally, we discuss the microbiome of the reproductive tract in health and during uterine diseases. As well, diagnostic criteria for metritis and endometritis and contributing factors for increased susceptibility to metritis infection are important topics of this review. To better understand how the uterus and reproductive tract respond to bacterial pathogens, a section of this review is dedicated to immunity of the reproductive tract. Both the innate and adaptive immunity systems are also discussed. We conclude the review with a factual discussion about the current treatments of uterine diseases and the new developments in the area of application of probiotics for uterine health. Mechanisms of actions of probiotics are discussed in detail and also some applications to prevent uterine infections in dairy cows are discussed.

Vaginal Microbiota Changes During Estrous Cycle in Dairy Heifers

The vaginal microbiota plays an important role in the health of dairy cattle, and it could be manipulated for the prevention and treatment of reproduction-related infections. The present study profiles and compares the vaginal microbiota of healthy dairy heifers during the estrous cycle focusing the results in follicular (estrus) and luteal (diestrus) phases using 16S rRNA sequencing of the V3-V4 hypervariable region. Twenty 13-16-months-old virgin dairy heifers from a single farm were included in this study. Vaginal swabs and blood samples were obtained during estrus (6-8 h before artificial insemination) and diestrus (14 days after insemination). Estrus was evaluated by an activity monitoring system and confirmed with plasma progesterone immunoassay. Results showed that the taxonomic composition of the vaginal microbiota was different during the follicular and luteal phases. At the phylum level, the most abundant bacterial phyla were Tenericutes, Firmicutes, and Bacteroidetes which comprised more than 75% of the vaginal microbiota composition. The next more abundant phyla, in order of decreasing abundance, were Proteobacteria, Actinobacteria, Fusobacteria, Epsilonbacteraeota, and Patescibacteria. Together with Tenericutes, Firmicutes, and Bacteroidetes represented more than 96% of the bacterial composition. Ureaplasma, Histophilus, f_Corynebacteriaceae, Porphyromonas, Mycoplasma, Ruminococcaceae UCG-005, were the most abundant genera or families. The results also showed that the vaginal microbiota of dairy heifers was non-lactobacillus dominant. The genus Lactobacillus was always found at a low relative abundance during the estrous cycle being more abundant in the follicular than in the luteal phase. Despite more research is needed to explore the potential use of native vaginal microbiota members as probiotics in dairy heifers, this study represents an important step forward. Understanding how the microbiota behaves in healthy heifers will help to identify vaginal dysbiosis related to disease.

Use of Probiotics in Intravaginal Sponges in Sheep: A Pilot Study

Simple Summary

The use of intravaginal devices may generate retention of vaginal secretions and abnormal discharges at device withdrawal, which may create changes in the normal vaginal bacterial microbiota. These changes in vaginal microbiota could allow the growth of opportunistic pathogenic bacteria which can require antibiotic treatment. The addition of antibiotics on sponges poses a risk of milk contamination. In dairy cows, it has been observed that the use of lactic acid bacteria (LAB) confers a health benefit to the reproductive tract against bacterial infections. However, LAB use in intravaginal sponges in sheep has not been reported. The aims of this study were to describe the dynamics of the ewes’s vaginal cultivable microbiota during a classic long-term estrous synchronization protocol and to develop a model of probiotic infusion in vaginal sponges in order to study their influence in ewe’s vaginal microbiota, general health status, fertility and prolificity. The present results suggest that LAB infusion in the ewe’s vagina do not affect general health status and did not reduce fertility during natural mating.

Abstract

Sheep estrous synchronization is mainly based on progestagen-impregnated sponges which could cause vaginitis. Several species of Lactobacillus used as probiotics are commonly used in the treatment or prevention of urogenital infections in humans. However, no studies have been performed to analyze the potential use of probiotics to prevent urogenital infections in sheep. A randomized controlled clinical trial was conducted with 21 one-year-old ewes to develop a model of probiotic infusion in vaginal sponges in order to study their influence in ewe’s vaginal microbiota, general health status, fertility and prolificity. Synchronization of estrus was based on intravaginal sponges for 14 days. Bacterial communities (Enterobacteriaceae and lactic acid bacteria) were highly fluctuating over time and between animals. The safety of probiotic infusion (mix of Lactobacillus spp. 60% L. crispatus, 20% L. brevis and 20% L. gasseri) in the vagina of healthy ewes was firstly confirmed. Neutrophils were observed in 80% (8/10) of the control ewes compared to 36% (4/11) of the ewes in the probiotic group 2 days after sponge removal (p = 0.056). Fertility in the control and probiotic groups was 60% (6/10) and 91% (10/11), respectively p = 0.097. These results suggest that Lactobacillus spp. infusion in the ewe’s vagina does not affect general health status or fertility.

Impact of yeast and lactic acid bacteria on mastitis and milk microbiota composition of dairy cows

This experiment was conducted to evaluate the impact of yeast and lactic acid bacteria (LAB) on mastitis and milk microbiota composition of dairy cows. Thirty lactating Holstein cows with similar parity, days in milk were randomly assigned to five treatments, including: (1) Health cows with milk SCC < 500,000 cells/mL, no clinical signs of mastitis were found, fed basal total mixed ration (TMR) without supplementation (H); (2) Mastitis cows with milk SCC > 500,000 cells/mL, fed basal TMR without supplementation (M); (3) Mastitis cows fed basal TMR supplemented with 8 g day^-1 yeast (M + Y); (4) Mastitis cows fed basal TMR supplemented with 8 g day^-1 LAB (M + L); (5) Mastitis cows (milk SCC > 500,000 cells/mL) fed basal TMR supplemented with 4 g day^-1 yeast and 4 g day^-1 LAB (M + Y + L). Blood and milk sample were collected at day 0, day 20 and day 40. The results showed efficacy of probiotic: On day 20 and day 40, milk SCC in H, M + Y, M + L, M + Y + L was significantly lower than that of M (P < 0.05). Milk concentration of TNF-α, IL-6 and IL-1β in M + Y + L were significantly reduced compared with that of M on day 40 (P < 0.05). Milk Myeloperoxidase (MPO) and N-Acetyl-β-D-Glucosaminidase (NAG) activity of M + Y, M + L, M + L + Y were lower than that of M on day 40 (P < 0.05). At genus level, Staphylococcus, Chryseobacterium and Lactococcus were dominant. Supplementation of LAB decreased abundance of Enterococcus and Streptococcus, identified as mastitis-causing pathogen. The results suggested the potential of LAB to prevent mastitis by relieving mammary gland inflammation and regulating milk microorganisms.

Could probiotics be the panacea alternative to the use of antimicrobials in livestock diets?

Probiotics are most frequently derived from the natural microbiota of healthy animals. These bacteria and their metabolic products are viewed as nutritional tools for promoting animal health and productivity, disease prevention and therapy, and food safety in an era defined by increasingly widespread antimicrobial resistance in bacterial pathogens. In contemporary livestock production, antimicrobial usage is indispensable for animal welfare, and employed to enhance growth and feed efficiency. Given the importance of antimicrobials in both human and veterinary medicine, their effective replacement with direct-fed microbials or probiotics could help reduce antimicrobial use, perhaps restoring or extending the usefulness of these precious drugs against serious infections. Thus, probiotic research in livestock is rapidly evolving, aspiring to produce local and systemic health benefits on par with antimicrobials. Although many studies have clearly demonstrated the potential of probiotics to positively affect animal health and inhibit pathogens, experimental evidence suggests that probiotics' successes are modest, conditional, strain-dependent, and transient. Here, we explore current understanding, trends, and emerging applications of probiotic research and usage in major livestock species, and highlight successes in animal health and performance.

Pre-calving Intravaginal Administration of Lactic Acid Bacteria Reduces Metritis Prevalence and Regulates Blood Neutrophil Gene Expression After Calving in Dairy Cattle

Metritis affects up to 40% of dairy cows and it is usually treated with antibiotics. In spite of their advantages, there is an increased concern about antibiotic resistance leading to the research of alternative methods. The aim of this study was to evaluate the effects of a combination of lactic acid bacteria (LAB) on the prevalence of metritis and modulation of endometrial and neutrophil inflammatory markers in dairy cows. One hundred and thirty-five cows were enrolled 3 week before calving and randomly assigned to three treatments. Treatment groups were: (1) two intravaginal doses of LAB/wk during 3 week pre-calving (vaginal, n = 45); (2) an intra-uterine dose, once 1 d after calving (uterine, n = 44); and (3) no intervention (CTRL, n = 45). Metritis was defined as body temperature > 39.5°C and purulent vaginal discharge (> 50% pus), and diagnosed 6 d after calving. Blood samples were taken at d −14, −10, −7, −4, +1, +3, +6, and +14 relative to calving for non-esterified fatty acids (NEFA) analysis. At d −10, +1, +3, and +6 neutrophils were isolated from blood for gene expression analysis by RT-qPCR. Endometrium biopsies were taken from 30 cows, 15 from CTRL and 15 from the uterine group at d +1, +3, and +6 after calving for pro-inflammatory markers analysis by NanoString®. Vaginal treatment reduced metritis prevalence (6/45) up to 58% compared with CTRL group (14/45), but there was no difference between the uterine and CTRL group. Uterine and vaginal treatments reduced blood neutrophil gene expression. Expression of pro-inflammatory markers in the endometrium did not differ between uterine and CTRL cows. Metritic cows expressed more C-X-C motif chemokine ligand 8 (CXCL8) and interleukin 1 beta (IL1B) at d 3 than healthy cows, whereas healthy cows expressed more CXCL8 at d 1 relative to calving in the endometrium. This study shows a promising potential of LAB probiotics as a preventive treatment against metritis in dairy cows.

Influence of intrauterine administration of Lactobacillus buchneri on reproductive performance and pro-inflammatory endometrial mRNA expression of cows with subclinical endometritis

Potential beneficial effects of lactic acid bacteria on the genital health of cows become of particular interest when considering the importance of an optimal uterine health status for the success of breeding in dairy farming. Therefore, the aim of the present study was to analyse the influence of an intrauterine administration of the Lactobacillus buchneri DSM 32407 on reproductive performance, uterine health status, endometrial mRNA expression of pro-inflammatory factors of cows with signs of subclinical endometritis (SCE). L. buchneri DSM 32407 (n = 56; [LAC]) or a placebo (n = 60; [PLA]) was administered on day 24–30 postpartum. Endometrial cytobrush samples of cows with SCE were taken before the administration and at three following weeks (n = 16 cows each for LAC/SCE and PLA/SCE). A higher proportion of cows of the LAC and LAC/SCE group was pregnant after the first service and median days to conception for cows pregnant on day 200 pp were shorter. Three weeks after the administration, the endometrial mRNA expression of CXCL1/2, CXCL3, CXCR2, IL1B, IL8 and PTPRC was lower in the LAC/SCE group compared with the PLA/SCE group. These findings suggest that the presence of L. buchneri DSM 32407 contributes to a uterine environment that results in a better reproductive performance.

Lactobacillus rhamnosus GR-1 Limits Escherichia coli-Induced Inflammatory Responses via Attenuating MyD88-Dependent and MyD88-Independent Pathway Activation in Bovine Endometrial Epithelial Cells

Intrauterine Escherichia coli infection after calving reduces fertility and causes major economic losses in the dairy industry. We investigated the protective effect of the probiotic Lactobacillus rhamnosus GR-1 on E. coli-induced cell damage and inflammation in primary bovine endometrial epithelial cells (BEECs). L. rhamnosus GR-1 reduced ultrastructure alterations and the percentage of BEECs apoptosis after E. coli challenge. Increased messenger RNA (mRNA) expression of immune response indicators, including pattern recognition receptors (toll-like receptor [TLR]2, TLR4, nucleotide-binding oligomerization domain [NOD]1, and NOD2), inflammasome proteins (NOD-like receptor family member pyrin domain-containing protein 3, apoptosis-associated speck-like protein, and caspase-1), TLR4 downstream adaptor molecules (myeloid differentiation antigen 88 [MyD88], toll-like receptor adaptor molecule 2 [TICAM2]), nuclear transcription factor kB (NF-kB), and the inflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-8, IL-10, IL-18, and interferon (IFN)-β, was observed following E. coli challenge. However, these increases were attenuated by L. rhamnosus GR-1 pretreatment. Our data indicate that L. rhamnosus GR-1 ameliorates the E. coli-induced disruption of cellular ultrastructure, subsequently reducing the percentage of BEECs apoptosis and limiting inflammatory responses, partly via attenuation of MyD88-dependent and MyD88-independent pathway activation. Certain probiotics could potentially prevent postpartum uterine diseases in dairy cows, ultimately reducing the use of antibiotics.

A combination of lactic acid bacteria regulates Escherichia coli infection and inflammation of the bovine endometrium

Uterine function in cattle is compromised by bacterial contamination and inflammation after calving. The objective of this study was to select a combination of lactic acid bacteria (LAB) to decrease endometrium inflammation and Escherichia coli infection. Primary endometrial epithelial cells were cultured in vitro to select the most favorable LAB combination modulating basal tissue inflammation and E. coli infection. Supernatants were obtained to determine expression of pro-inflammatory cytokines, and E. coli infection was evaluated after harvesting the tissue and plate counting. The selected LAB combination was tested in uterus explants to assess its capacity to modulate basal and acute inflammation (associated with E. coli infection). The combination of Lactobacillus rhamnosus, Pediococcus acidilactici, and Lactobacillus reuteri at a ratio of 25:25:2, respectively, reduced E. coli infection in vitro with (89.77%) or without basal tissue inflammation (95.10%) compared with single LAB strains. Lactic acid bacteria treatment reduced CXCL8 and IL1B expression 4.7- and 2.2-fold, respectively, under acute inflammation. Ex vivo, the tested LAB combination reduced acute inflammation under E. coli infection, decreasing IL-8, IL-1β, and IL-6 up to 2.2-, 2.5-, and 2.2-fold, respectively. In the total inflammation model, the LAB combination decreased IL-8 1.6-fold and IL-6 1.2-fold. Ultrastructural evaluation of the tissue suggested no direct interaction between the LAB and E. coli, although pathological effects of E. coli in endometrial cells were greatly diminished or even reversed by the LAB combination. This study shows the promising potential of LAB probiotics for therapeutic use against endometrial inflammation and infection.