Probiotic use in horses - what is the evidence for their clinical efficacy?

Lactiplantibacillus brownii sp. nov., a novel psychrotolerant species isolated from sauerkraut

A Gram-stain-positive, rod-shaped, facultatively anaerobic and homofermentative strain, named WILCCON 0030T, was isolated from sauerkraut (fermented cabbage) collected from a local market in the Moscow region of Russia. Comparative analyses based on 16S rRNA gene sequence similarity and whole genome relatedness indicated that strain WILCCON 0030T was most closely related to the type strains Lactiplantibacillus nangangensis NCIMB 15186T, Lactiplantibacillus daoliensis LMG 31171T and Lactiplantibacillus pingfangensis LMG 31176T. However, the average nucleotide identity and digital DNA-DNA hybridization prediction values with these closest relatives only ranged from 84.6 to 84.9 % and from 24.1 to 24.7 %, respectively, and were below the 95.0 and 70.0% thresholds for species delineation. Substantiated by further physiological and biochemical analyses, strain WILCCON 0030T represents a novel species within the genus Lactiplantibacillus for which we propose the name Lactiplantibacillus brownii sp. nov. (type strain WILCCON 0030T=DSM 116485T=LMG 33211T).

Beneficial Bacteria Isolated from Food in Relation to the Next Generation of Probiotics

Recently, probiotics are increasingly being used for human health. So far, only lactic acid bacteria isolated from the human gastrointestinal tract were recommended for human use as probiotics. However, more authors suggest that probiotics can be also isolated from unconventional sources, such as fermented food products of animal and plant origin. Traditional fermented products are a rich source of microorganisms, some of which may have probiotic properties. A novel category of recently isolated microorganisms with great potential of health benefits are next-generation probiotics (NGPs). In this review, general information of some "beneficial microbes", including NGPs and acetic acid bacteria, were presented as well as essential mechanisms and microbe host interactions. Many reports showed that NGP selected strains and probiotics from unconventional sources exhibit positive properties when it comes to human health (i.e., they have a positive effect on metabolic, human gastrointestinal, neurological, cardiovascular, and immune system diseases). Here we also briefly present the current regulatory framework and requirements that should be followed to introduce new microorganisms for human use. The term "probiotic" as used herein is not limited to conventional probiotics. Innovation will undoubtedly result in the isolation of potential probiotics from new sources with fascinating new health advantages and hitherto unforeseen functionalities.

Donkey Colostrum and Milk: How Dietary Probiotics Can Affect Metabolomic Profile, Alkaline Sphingomyelinase and Alkaline Phosphatase Activity

Positive results on animal health, feed efficiency, and milk's nutritional content have been obtained after oral administration of probiotics. The aim of the present study was therefore to evaluate the effect of dietary supplementation with high numbers of multispecies probiotic formulations on the milk metabolomic profiles of alkaline sphingomyelinase (alk-SMase) and alkaline phosphatase (ALP) in donkeys. Twenty animals were randomly allocated to receive either a normal diet (group B) or a supplemented diet (group A). Colostrum and milk samples were obtained within 48 h, at 15 days (supplementation start), and at 45 days after parturition. Different metabolomic profiles were observed between colostrum and milk, as were the concentrations of 12 metabolites that changed following 30 days of probiotic supplementation. Alk-SMase activity was found to be higher in donkey colostrum (vs. milk at 15 days); this enzyme, together with ALP, increased in milk after 30 days of probiotic supplementation. The results of the present study provide new insight into the complex changes in donkey colostrum and milk composition in the first 45 days of lactation and how the milk metabolome can be modulated by probiotic supplementation.

Recurrent Colic: Diagnosis, Management, and Expectations

Most recurrent episodes of non-specific colic are self-limiting, and the results of clinical examinations are unremarkable. Differentiating these cases from serious diseases can be difficult, but repeated evaluations are warranted. Horses presenting with very frequent bouts of colic are more likely to have serious diseases and a higher mortality rate compared to horses presenting with less frequent bouts of transient colic. Horses with recurrent bouts of prolonged colic are more likely to have motility issues or partial intestinal obstruction. Non-gastrointestinal diseases can also cause recurrent bouts of pain ("false colic"). Adhesions are common causes of colic following abdominal surgery.

Evaluation of Bacterial Composition and Viability of Equine Feces after Processing for Transplantation

Fecal microbiota transplantation (FMT) has been used empirically for decades in equine medicine to treat intestinal dysbiosis but evidence-based information is scarce. This in vitro study aimed at assessing the effect of a commonly used pre-FMT processing method on the bacterial composition and viability of the fecal filtrate. Three samples of fresh equine manure (T₀) were processed identically: the initial manure was mixed with 1 L of lukewarm water and chopped using an immersion blender to obtain a mixture (T₁), which was left uncovered during 30 min (T₂) and percolated through a sieve to obtain a fecal filtrate (T₃). Samples were taken throughout the procedure (Tn) and immediately stored at 4 °C until processing. The 16S rDNA amplicon profiling associated with propidium monoazide treatment was performed on each sample to select live bacteria. Analyses of α and β diversity and main bacterial populations and quantitative (qPCR) analysis were performed and statistically compared (significance p < 0.05) between time points (T₀-T₃). No significant differences in ecological indices or mean estimated total living bacteria were found in the final fecal filtrate (T₃) in regard to the original manure (T₀); however, relative abundances of some minor genera (Fibrobacter, WCHB1-41_ge and Akkermansia) were significantly different in the final filtrate. In conclusion, the results support the viability of the major bacterial populations in equine feces when using the described pre-FMT protocol.

The influence of a probiotic/prebiotic supplement on microbial and metabolic parameters of equine cecal fluid or fecal slurry in vitro

The microbes that reside within the equine hindgut create a complex and dynamic ecosystem. The equine hindgut microbiota is intimately associated with health and, as such, represents an area which can be beneficially modified. Synbiotics, supplements that combine probiotic micro-organisms with prebiotic ingredients, are a potential means of influencing the hindgut microbiota to promote health and prevent disease. The objective of the current study was to evaluate the influence of an equine probiotic/prebiotic supplement on characteristics of the microbiota and metabolite production in vitro. Equine cecal fluid and fecal material were collected from an abattoir in QC, CAN. Five hundred milliliters of cecal fluid was used to inoculate chemostat vessels maintained as batch fermenters (chemostat cecal, N = 11) with either 0 g (control) or 0.44 g of supplement added at 12 h intervals. One hundred milliliters of cecal fluid (anaerobic cecal, N = 15) or 5% fecal slurry (anaerobic fecal, N = 6) were maintained in an anaerobic chamber with either 0 g (control) or 0.356 g of supplement added at the time of vessel establishment. Samples were taken from vessels at vessel establishment (0), 24, or 48 h of incubation. Illumina sequencing of the V4 region of the 16S rRNA gene and bioinformatics were performed for microbiome analysis. Metabolite data was obtained via NMR spectroscopy. All statistical analyses were run in SAS 9.4. There was no effect of treatment at 24 or 48h on alpha or beta diversity indices and limited taxonomic differences were noted. Acetate, propionate, and butyrate were higher in treated compared to untreated vessels in all methods. A consistent effect of supplementation on the metabolic profile with no discernable impact on the microbiota of these in vitro systems indicates inoculum microbe viability and a utilization of the provided fermentable substrate within the systems. Although no changes within the microbiome were apparent, the consistent changes in metabolites indicates a potential prebiotic effect of the added supplement and merits further exploration.

The Role of Yeast Saccharomyces cerevisiae in Supporting Gut Health in Horses: An Updated Review on Its Effects on Digestibility and Intestinal and Fecal Microbiota

To support the overall health of horses, it is essential to maintain an optimal gut health (GH) status, which encompasses several physiological and functional aspects, including the balance and functionality of intestinal microbial populations and, accordingly, the effective digestion and absorption of nutrients. Numerous biotic and abiotic stressors can lead to an imbalance of GH, such as the quality of forages and the composition of diet, e.g., the inclusion of high energy-dense feeds to meet the energy requirements of performance horses. To support the digestive function and the intestinal microbial populations, the diet can be supplemented with feed additives, such as probiotic yeasts, that promote the ability of cellulolytic bacteria in the hindgut to digest the available fiber fractions, finally increasing feed efficiency. Among the different yeasts available, S. cerevisiae is the most used in horses' nutrition; however, results of digestibility trials, as well as data on intestinal and fecal microbial populations, are sometimes contradictory. Therefore, the purpose of this review is to summarize the effects of S. cerevisiae on in vivo and in vitro digestibility, providing an updated overview of its effects on the intestinal and fecal microbial population.

Clostridioides difficile infection and One Health: An Equine Perspective

Clostridioides (Clostridium) difficile presents a significant health risk to humans and animals. The complexity of the bacterial–host interaction affecting pathogenesis and disease development creates an ongoing challenge for epidemiological studies, control strategies and prevention planning. The recent emergence of human disease caused by strains of C. difficile found in animals adds to mounting evidence that C. difficile infection (CDI) may be a zoonosis. In equine populations, C. difficile is a known cause of diarrhoea and gastrointestinal inflammation, with considerable mortality and morbidity. This has a significant impact on both the well‐being of the animal and, in the case of performance and production animals, it may have an adverse economic impact on relevant industries. While C. difficile is regularly isolated from horses, many questions remain regarding the impact of asymptomatic carriage as well as optimization of diagnosis, testing and treatment. This review provides an overview of our understanding of equine CDI while also identifying knowledge gaps and the need for a holistic One Health approach to a complicated issue.

Probiotic Characterization of Indigenous Kocuria flava Y4 Strain Isolated from Dioscorea villosa Leaves

This aim of the study was to isolate and screen potential probiotics from Dioscorea villosa leaves. The potential isolate Y4 was obtained from the Dioscorea villosa leaves, and its ability to grow in a medium containing high NaCl concentrations (2-10%) indicated its negative hemolytic activity. Furthermore, Y4 demonstrated inhibitory activity against human pathogens, such as Klebsiella pneumonia, Staphylococcus aureus, Citrobacter koseri, and Vibrio cholerae, as well as towards a plant pathogen isolate OR-2 (obtained from Citrus sinensis). Some biologically important functional groups of Y4 metabolites, such as sulfoxide; aliphatic ether; 1, 2, 3-trisubstituted, tertiary alcohol: vinyl ether; aromatic amine; carboxylic acid; nitro compound; alkene mono-substituted; and alcohol, were identified through FTIR analysis. The 16S rRNA sequencing and subsequent phylogenetic tree analysis indicated that Y4 and OR-2 are the closest neighbors to Kocuria flava (GenBank accession no. MT773277) and Pantoea dispersa (GenBank accession no. MT766308), respectively. The potential isolate Y4 was found to exhibit adhesion, auto-aggregation, co-aggregation, and weak biofilm activity. It also exhibited a high level of antimicrobial activity and antibiotic susceptibility. The safety of K. flava Y4 isolate, which is proposed to be a probiotic, was evaluated through acute oral toxicity test and biogenic amine production test. Moreover, the preservation potential of isolate Y4 was assessed through application on fruits under different temperatures. Thus, our results confirmed that Kocuria flava Y4 is a prospective probiotic and could also be used for the preservation of fruits.

Assessment on In Vitro Probiotic Attributes of Lactobacillus plantarum Isolated From Horse Feces

This study was designed to assess in vitro probiotic attributes of potent bacterium isolated from the feces of healthy horse. Initially, a total of eight bacteria were isolated from the feces and evaluated their antibacterial activities against indicator bacterial pathogens using agar well diffusion assay. Results showed significant (P < .05) antibacterial property of Lactobacillus plantarum strain LF4 against pathogens tested with maximum growth inhibitory activity of 320.16 ± 3.4 AU/mL against Staphylococcus aureus. Further, in vitro probiotic properties of strain LF4 were determined using standard methodologies. Strain LF4 maintained its viability towards acidic condition (pH 2.0) and simulated gastric juice (pH 2.0) with total cell counts of 1.6 ± 0.18 and 1.7 ± 0.18 log cfu/mL, respectively. Moreover, the strain was observed resistant to oxgall (0.5% w/v) up to 36 hours. The isolate showed significant (P < .05) hydrophobicity property (60.3 ± 1.6%), auto-aggregation trait (41.31 ± 1.5%), and moderate proteolytic activity. Strain LF4 revealed significant (P < .05) rate of DPPH scavenging (15.3 ± 1.3-69.7 ± 1.3%) and hydroxyl radical scavenging (11.3 ± 1.3 to 56.4 ± 1.3%) in a concentration dependent manner. Additionally, the isolate was observed susceptible to all the conventional antibiotics tested, thereby indicating its safer utilization. In conclusion, findings suggested the colossal applications of L. plantarum strain LF4 as an ideal probiotic bacterium in equine industries.

Microbial Variability of Commercial Equine Probiotics

Probiotics are defined as live microorganisms that confer a health benefit to the host when administered in adequate amounts, therefore the presence of viable microorganisms is essential. Previous studies reported inconsistencies when comparing contents of probiotics marketed for use in animals with label claims. However, to the author's knowledge the variability of the same product between different lots has yet to be evaluated. The objective of this observational study was to evaluate the content and inter-lot variability of commercial equine probiotic products using culture dependent and independent techniques. Eleven probiotics marketed for use in horses were evaluated for microbial content using culture-dependent and independent techniques. The content was then compared to microorganisms listed and quantities on the label of the probiotic. Statistical analyses were performed using a Kruskal-Wallis test. None of the 11 probiotics met their label claim. Nine of the 11 did not have statistically significant inter-lot variability. Several products lacked microorganisms listed on the label based on both culture and polymerase chain reaction (PCR) analyses.

Gut Microbiota Manipulation in Foals-Naturopathic Diarrhea Management, or Unsubstantiated Folly?

Diarrhea in foals is a problem of significant clinical and economic consequence, and there are good reasons to believe microbiota manipulation can play an important role in its management. However, given the dynamic development of the foal microbiota and its importance in health and disease, any prophylactic or therapeutic efforts to alter its composition should be evidence based. The few clinical trials of probiotic preparations conducted in foals to date show underwhelming evidence of efficacy and a demonstrated potential to aggravate rather than mitigate diarrhea. Furthermore, recent studies have affirmed that variable but universally inadequate quality control of probiotics enables inadvertent administration of toxin-producing or otherwise pathogenic bacterial strains, as well as strains bearing transferrable antimicrobial resistance genes. Consequently, it seems advisable to approach probiotic therapy in particular with caution for the time being. While prebiotics show initial promise, an even greater scarcity of clinical trials makes it impossible to weigh the pros and cons of their use. Advancing technology will surely continue to enable more detailed and accurate mapping of the equine adult and juvenile microbiota and potentially elucidate the complexities of causation in dysbiosis and disease. In the meantime, fecal microbiota transplantation may be an attractive therapeutic shortcut, allowing practitioners to reconstruct a healthy microbiota even without fully understanding its constitution.

Enterocin M-Producing Enterococcus faecium CCM 8558 Demonstrating Probiotic Properties in Horses

The effects of non-authochtonous Enterococcus faecium AL41 = CCM 8558, enterocin M-producing and probiotic strain were tested on the microbiota, phagocytic activity, hydrolytic enzymes, biochemical parameters and dry matter in horses based on its previous benefits demonstrated in other animals. E. faecium CCM 8558 sufficiently colonized the digestive tract of horses. At day 14, its counts reached 2.35 ± 0.70 CFU/g (log 10) on average. The identity of CCM 8558 was confirmed by means of PCR after its re-isolation from horse faeces. The inhibition activity of CCM 8558 was demonstrated against Gram-negative aeromonads, counts of which were significantly reduced (P < 0.001). After 14 days application of CCM 8558, a tendency towards increased phagocytic activity (PA) was measured; PA value was 73.13% ± 8.55 on average at day 0/1; at day 14, it was 75.11 ± 8.66%. Cellulolytic, xylanolytic and pectinolytic activity in horse faeces was significantly increased (P < 0.001) at day 14 (after CCM 8558 application) and amylolytic activity as well (P < 0.01) compared to day 0/1. Inulolytic activity increased with mathematical difference 1.378. Dry matter value reached 20.81 ± 2.29% on average at day 0/1; at day 14, it was 20.77 ± 2.59% (P = 0.9725). Biochemical parameters were influenced mostly in the physiological range. These results achieved after application of CCM 8558 in horses are original, giving us further opportunity to continue these studies, to measure additional parameters and to show the benefits of CCM 8558 application in horses.

NEONATAL INTENSIVE CARE OF 10 HOSPITALIZED GIRAFFE CALVES (GIRAFFA CAMELOPARDALIS) REQUIRING HAND-REARING

This retrospective case series describes the clinicopathologic findings, diagnoses, treatment, and outcomes of 10 hand-reared newborn giraffe (Giraffa camelopardalis) calves admitted to a university teaching hospital for intensive care. Ten calves (five males, five females; nine reticulated giraffes [Giraffa camelopardalis reticulata], one Masai giraffe [G. c. tippelskirchi]), were admitted under 2 days of age. Inadequate transfer of passive immunity was suspected in 5 of 10 calves based on assessment of serum total solids and globulin values. These calves were treated with oral frozen bovine colostrum and/or intravenous hyperimmune bovine plasma. Diarrhea occurred in 6 of 10 calves and was managed with supportive care, fecal microbiota transplantation, and limiting milk intake (offering 10% body weight [BW] in milk per day, while feeding <2 L per meal at 2- to 4-hr intervals). Less common diagnoses included pneumonia (n = 3) and mycoplasma-associated septic arthritis (n = 1). Eight calves received systemic antimicrobial therapy. Hyperlactatemia (lactate > 5 mmol/L; n = 8) and hypercreatininemia (creatinine > 2.0 mg/dl, n = 7) were the most common presenting laboratory abnormalities, which resolved with intravenous fluid therapy. All neonatal giraffes survived to discharge after a median hospitalization of 9.5 days (range, 5-37 days) and were successfully hand-reared at their place of birth. In conclusion, neonatal giraffe calves can be intensively managed in a hospital environment. Diarrhea was a common clinical problem and can be related to feeding regimens. Intravenous hyperimmune bovine plasma infusion was well tolerated to manage failure of transfer of passive immunity in calves with inadequate colostrum administration. The current study supports that compromised neonatal giraffe calves may carry an excellent prognosis after early, intensive intervention.

Effect of probiotics administration at different levels on the productive parameters of guinea pigs for fattening (Cavia porcellus)

Background

For more than 50 years, antibiotics have been used to maintain animal welfare and improve efficiency. Recently, antibiotics were found in the muscle, liver, and kidney of guinea pig carcasses put up for sale and human consumption, which is a public health issue. Probiotics are supplements of live microorganisms that, when administered in adequate doses, could replace growth-promoting antibiotics.

Aim

This study analyzed the effect of the administration of an oral probiotic mixture on the guinea pigs productive performance (Cavia porcellus).

Methods

Fifty male guinea pigs, weaned at 14 days of age, were distributed in a completely randomized design of five treatments with ten repetitions for each group. The treatments were CONTROL group without probiotic; PROB 1 given 1 ml of probiotic; PROB 2 with 2 ml of probiotic; PROB 3 with 3 ml of probiotic; and antibiotic growth promoter (AGP) was given 300 ppm zinc bacitracin. The microorganisms used in the probiotic were Enterococcus hirae, Lactobacillus reuteri, Lactobacillus frumenti, Lactobacillus johnsoni, Streptococcus thoraltensis, and Bacillus pumilus. Productive parameters were evaluated from weaning to 70 days of age.

Results

No statistically significant difference was found between the treatments on forage dry matter intake (DMI), concentrateconcentrate DMI, or total concentrate DMI (p > 0.05). Similarly, no statistical difference was found between the treatments in terms of final weight or weight gain (p > 0.05). Regarding the feed conversion ratio (FCR), there was a significant difference between treatments (p = 0.045); the CONTROL group had the highest FCR, followed by the AGP group, with the best FCR observed in the PROB 3 group (p < 0.05). In addition, significant statistical differences were found between CONTROL and PROB 2 (p < 0.05). Likewise, a significant linear effect of increasing doses of the probiotic was found (p = 0.01), which indicated that the feed conversion was better with a higher dose.

Conclusion

The treatments evaluated in this study significantly impacted the FCR in guinea pigs for fattening. Increasing doses of probiotics had a linear effect on FCR.

The Safety, Tolerability and Efficacy of Probiotic Bacteria for Equine Use

Probiotic bacteria are used widely as nutritional supplements and treatment interventions in the management of livestock and companion animals. The aim of this review is to summarize the current evidence reporting on the safety, tolerability and efficacy of probiotic bacteria use in horses. An online search of five databases for studies reporting on the use of probiotic bacteria use in horses which were either healthy or had a gastrointestinal or extraintestinal disease was conducted. A total of 18 articles were eligible for full review. No clear benefits were identified to support supplementation of equids with probiotic bacteria to improve starch and fiber digestion, nor for the treatment of colic or prevention of salmonellosis. Conflicting results were seen with the management of scouring in neonatal foals. Exacerbation of diarrhea and additional adverse events were reported in response to the administration of high doses of novel probiotic bacterial species. Probiotic bacteria given to exercising horses, improved aerobic fitness and stamina. The majority of probiotic bacterial species used in equine studies are bacterial species commonly used for human consumption and indigenous to the human gastrointestinal microbiota. There is a paucity of evidence to support the use of probiotic bacteria in the health maintenance and disease management of horses. While there are unclear and conflicting results associated with probiotic bacteria use for gastrointestinal conditions in both horses and foals, the administration of multistrain bacterial formulations to increase stamina in exercising horses shows promise.

Effect of Feeding Fructooligosaccharides and Enterococcus faecium and Their Interaction on Digestibility, Blood, and Immune Parameters of Adult Horses

The objectives of this study were to determine the effects of dietary prebiotic fructooligosaccharides (FOS) from inulin and Enterococcus faecium on nutrient digestibility, fecal pH, and some blood parameters. In this experiment, twelve adult Kurdish horses with average bogy weight of 416 ± 43.3 kg and age averaging 6 ± 1.8 year were used in a replicated 4 × 4 Latin Square experiment with a 2 × 2 factorial design during 4 periods of 28 days, including 21 days for dietary adaptation and 7 days for sampling. Horses were offered 1 of 4 treatments: (1) no FOS or 2.5 × 10¹¹ colony forming units (CFU) of Enterococcus faecium supplementation (Con), (2) 10 g of FOS without Enterococcus faecium supplementation (Pre), (3) 10 g of Enterococcus faecium without FOS supplementation (Pro), and (4) 10 g of FOS plus 10 g of Enterococcus faecium supplementation (Mix). Results showed that fecal pH decreased in horses fed Pre or Pro treatments compared with those not supplemented (P < .05). Also, triglyceride and cholesterol decreased when Pre was added to the diets (P < .05). The concentration of triglyceride and cholesterol decreased in horses fed the Mix and Pro diets. Pre × Pro supplementation interactions were significant for high-density lipoprotein (HDL) concentration and tended to be significant for low-density lipoprotein (LDL) concentration, and horses fed the Mix treatment had the greatest and the lowest concentration of HDL and LDL, respectively (P < .01). The IgM concentration was greater in horses fed Pre or Pro compared with those not supplemented (P < .05). The treatments had no effect on IgA, IgG or liver enzymes concentration. Moreover, results indicated that FOS and Enterococcus faecium adding may interact to affect blood parameters, but did not affect nutrient digestibility under our experimental conditions, therefore further researches with higher supplementary doses are warranted.

Equine nutrition in the post-operative colic: Survey of Diplomates of the American Colleges of Veterinary Internal Medicine and Veterinary Surgeons, and European Colleges of Equine Internal Medicine and Veterinary Surgeons

Background

Evidence is lacking concerning re‐introduction of feed and water following colic surgery.

Objectives

To describe current approaches of European and American specialists to re‐introduction of feed and water in adult horses following surgical treatment of common intestinal lesions, assuming an uncomplicated recovery.

Study design

Cross‐sectional survey.

Methods

Electronic invitations, with a link to the online survey, were sent to 1,430 large animal specialists, including Diplomates of the ECVS, ACVS, ECEIM and ACVIM colleges.

Results

The response rate was 12.6% including partial respondent data. Responses for each multiple‐choice question were between 123 and 178. Results are expressed as the percentage of the total number of responses and as a range where specific lesions are grouped together. Respondents reported that horses with large intestinal displacements were offered free choice water (63%‐65%) within 3 hours (55%‐63%), whereas horses with a small intestinal strangulating lesion were offered < 2 L water (64%‐74%) 12‐24 hours (28%‐34%) post‐operatively. Horses with a large colon displacement were offered feed within 3 hours of surgery (16%) with the majority offered feed 6‐12 hours (35%‐36%) post‐operatively. Horses with small intestinal strangulating lesions and small colon lesions were offered feed 24‐48 hours (34%‐42%) after surgery. Following small intestinal, small colon or caecal lesions, horses were re‐introduced feed in handfuls (79%‐93%) and initially with grass (41%‐54%). Horses with large colon displacements were mostly fed handfuls (49%‐50%) of forage initially, but a number of respondents would offer larger quantities such as a small bucket (35%‐37%) and predominantly of hay (50%‐51%).

Main limitations

Low response rate. This study did not take into account common post‐operative complications that may alter the clinical approach.

Conclusions

This post‐operative colic nutrition survey is the first to describe current clinical practice. Further research is required to investigate nutritional strategies in post‐operative colic cases.

No Worm Is an Island; The Influence of Commensal Gut Microbiota on Cyathostomin Infections

Simple Summary

There is increasing evidence for the importance of gut bacteria in animal health and disease. This is particularly relevant for gastrointestinal infections, such as parasitic worms, which share a niche with gut bacteria. Parasitic worms are highly prevalent in domestic horses and are a significant cause of disease in this population. This commentary explores the complex relationships between the most common parasitic worm in horses (cyathostomins) and gut bacteria, based on recent studies in horses and other species. We propose novel theories and avenues for research that harness these relationships and have the potential to improve control of parasitic worms, and overall equine health, in the future.

Abstract

The importance of the gut microbiome for host health has been the subject of intense research over the last decade. In particular, there is overwhelming evidence for the influence of resident microbiota on gut mucosal and systemic immunity; with significant implications for the outcome of gastrointestinal (GI) infections, such as parasitic helminths. The horse is a species that relies heavily on its gut microbiota for GI and overall health, and disturbances in this complex ecosystem are often associated with life-threatening disease. In turn, nearly all horses harbour parasitic helminths from a young age, the most prevalent of which are the small strongyles, or cyathostomins. Research describing the relationship between gut microbiota and cyathostomin infection is in its infancy, however, to date there is evidence of meaningful interactions between these two groups of organisms which not only influence the outcome of cyathostomin infection but have long term consequences for equine host health. Here, we describe these interactions alongside supportive evidence from other species and suggest novel theories and avenues for research which have the potential to revolutionize our approach to cyathostomin prevention and control in the future.

The evaluation of the effect of probiotics on the healing of equine distal limb wounds

The effect of dressings saturated with either a standardized suspension of probiotic bacteria or saline on healing of traumatic distal limb wounds in horses was evaluated for 24 days, and the systemic inflammatory effect was assessed. The wounds were divided in two groups based on the phase of healing: wounds with an incomplete (ICGB) or a complete granulation bed (CGB). The wound area was expressed as percentage of the wound area at day 0 and defined as relative wound area. The mean relative wound area decreased faster in probiotic than saline treated wounds. The difference was most obvious in CGB and increased rapidly from day 0 until day 12 up to 30%, and stabilized around 25% thereafter until the end of the observation period, but it was not statistically significant because of the large variation within the treatment groups. The mean wound area of CGB decreased to 28.4% (range: 6.3 to 49.3) with probiotic and to 51.9% (range: 29.3 to 81.7) with saline treatment at day 24. Additionally, the rate to 50% healing in CGB was 3.4 faster with probiotic compared to saline treatment, whereas in ICGB this was 1.9 faster. Topical probiotics did not increase serum amyloid A and white blood cell counts. Although the mentioned differences were not statistically significant, the clinical relevance of the effect of treatment with probiotics in CGB wounds is clear, supported by the differences in mean wound area in course of time and the time required to reach 50% healing (day 12 for probiotic vs more than day 24 for saline treated wounds). Thus the probiotic treated wounds reached 50% reduction in wound area in half of the time of the saline treated wounds. The topical use of probiotics can be considered as safe as it did not cause a systemic effect.

The effect of supplementing pony diets with yeast on 1. In vivo and in vitro digestibility, faecal pH and particle size

Fibre is essential to maintain healthy gut; however, energy demands of performance horses can be too high to be met by forages alone. Yeast may support the function of cellulolytic bacteria to digest fibre. The aim of this work was to determine the effect of an oral supplement (VistaEQ) containing 4% live yeast on the in vitro and in vivo digestibility of high-starch (HS) and high-fibre diets (HF). Eight ponies were used in a 4 × 4 Latin square design consisting of 4- × 19-day periods and four diets: HF, HF + yeast (HFY), HS and HS + yeast (HSY). In vivo apparent digestibility (AD) was estimated using total collection technique, and faecal particle size was measured using NASCO digestive analyser. Faeces from the ponies were subsequently used as an inoculum in ANKOM RF gas production system to assess fermentation kinetics in vitro. Each module contained 1 g of feed substrate DM in the following combinations: 50% grass hay and 50% alfalfa (HF_50 : 50) or concentrate (HS_50 : 50), and 75% grass hay and 25% alfalfa (HF_75 : 25) or concentrate (HS_75 : 25) with or without yeast. Yeast was able to induce more gas production from HF_75 : 25, HS_75 : 25 and HF_50 : 50 feed substrates incubated with respective faecal inoculum base. Yeast did not affect pH in vitro when the substrates were incubated in 50 : 50 ratio, while the pH was higher for HF_75 : 25 incubated with correspondent faecal inoculum compared to HS_75 : 25 and HSY_75 : 25. Yeast had no effects on ADF and CP AD of either diet. Yeast addition increased DM (HF: 0.2%, HS: 0.4%), organic matter (HF: 0.7%, HS: 1.3%), NDF (HF: 0.5%, HS: 1.5%), total detergent fibre (HF: 0.7%; HS: 0.4%) (P < 0.05) and also tended to increase hemicellulose AD (HF: 0.9%, HS: 1.2%) (P < 0.10). Faecal pH in vivo was higher for both HF diets compared to HS diet without yeast supplementation (P < 0.001, HF and HFY: 6.8; HS: 6.6, HSY: 6.7). However, no difference was observed in faecal pH when HSY was compared to both HF diets. Yeast had no effect on the size of the faecal particles (P > 0.05). Yeast increased in vitro gas production, suggesting more energy could be extracted from the feed, and the in vivo AD of some of the nutrients when HF and HS diets were fed.

The fecal microbiota of healthy donor horses and geriatric recipients undergoing fecal microbial transplantation for the treatment of diarrhea

BACKGROUND AND AIMS

Fecal microbial transplantation (FMT), a treatment for certain gastrointestinal conditions associated with dysbiosis in people, is also empirically employed in horses with colitis. This study used microbiota high-throughput sequencing to compare the fecal microbial profile of healthy horses to that of geriatric microbial transplant recipients experiencing diarrhea and tested whether FMT restores microbiota diversity.

METHODS

To evaluate the effect of environment and donor characteristics on the intestinal microbiota, fecal samples were collected per rectum from 15 healthy young-adult (2-12 years) and 15 geriatric (≥20 years) horses. Additionally, FMT was performed for 3 consecutive days in 5 geriatric horses with diarrhea using feces from the same healthy donor. Fecal samples were collected from both donor and recipient prior to each FMT and from recipients 24 hours following the last FMT. The profile of the fecal bacterial microbiota was compared using 16S amplicon sequencing.

RESULTS AND CONCLUSIONS

In contrast to diet and farm location, age did not significantly affect the healthy equine fecal microbiota, indicating that both healthy geriatric and young-adult horses may serve as FMT donors. The fecal microbiota of horses with diarrhea was significantly more variable in terms of β-diversity than that of healthy horses. An inverse correlation between diarrhea score and relative abundance of Verrucomicrobia was identified in surviving FMT recipients. At study completion, the fecal microbiota of horses which responded to FMT had a higher α-diversity than prior to treatment and was phylogenetically more similar to that of the donor.

Factors Influencing Equine Gut Microbiota: Current Knowledge

Gastrointestinal microbiota play a crucial role in nutrient digestion, maintaining animal health and welfare. Various factors may affect microbial balance often leading to disturbances that may result in debilitating conditions such as colic and laminitis. The invention of next-generation sequencing technologies and bioinformatics has provided valuable information on the effects of factors influencing equine gut microbiota. Among those factors are nutrition and management (e.g., diet, supplements, exercise), medical substances (e.g., antimicrobials, anthelmintics, anesthetics), animal-related factors (breed and age), various pathological conditions (colitis, diarrhea, colic, laminitis, equine gastric ulcer syndrome), as well as stress-related factors (transportation and weaning). The aim of this review is to assimilate current knowledge on equine microbiome studies, focusing on the effect of factors influencing equine gastrointestinal microbiota. Decrease in microbial diversity and richness leading to decrease in stability; decrease in Lachnospiraceae and Ruminococcaceae family members, which contribute to gut homeostasis; increase in Lactobacillus and Streptococcus; decrease in lactic acid utilizing bacteria; decrease in butyrate-producing bacteria that have anti-inflammatory properties may all be considered as a negative change in equine gut microbiota. Shifts in Firmicutes and Bacteroidetes have often been observed in the literature in response to certain treatments or when describing healthy and unhealthy animals; however, these shifts are inconsistent. It is time to move forward and use the knowledge now acquired to start manipulating the microbiota of horses.

The gut microbiome of horses: current research on equine enteral microbiota and future perspectives

Understanding the complex interactions of microbial communities including bacteria, archaea, parasites, viruses and fungi of the gastrointestinal tract (GIT) associated with states of either health or disease is still an expanding research field in both, human and veterinary medicine. GIT disorders and their consequences are among the most important diseases of domesticated Equidae, but current gaps of knowledge hinder adequate progress with respect to disease prevention and microbiome-based interventions. Current literature on enteral microbiomes mirrors a vast data and knowledge imbalance, with only few studies tackling archaea, viruses and eukaryotes compared with those addressing the bacterial components.Until recently, culture-dependent methods were used for the identification and description of compositional changes of enteral microorganisms, limiting the outcome to cultivatable bacteria only. Today, next generation sequencing technologies provide access to the entirety of genes (microbiome) associated with the microorganisms of the equine GIT including the mass of uncultured microbiota, or "microbial dark matter".This review illustrates methods commonly used for enteral microbiome analysis in horses and summarizes key findings reached for bacteria, viruses and fungi so far. Moreover, reasonable possibilities to combine different explorative techniques are described. As a future perspective, knowledge expansion concerning beneficial compositions of microorganisms within the equine GIT creates novel possibilities for early disorder diagnostics as well as innovative therapeutic approaches. In addition, analysis of shotgun metagenomic data enables tracking of certain microorganisms beyond species barriers: transmission events of bacteria including pathogens and opportunists harboring antibiotic resistance factors between different horses but also between humans and horses will reach new levels of depth concerning strain-level distinctions.

Dysbiosis associated with acute helminth infections in herbivorous youngstock - observations and implications

A plethora of data points towards a role of the gastrointestinal (GI) microbiota of neonatal and young vertebrates in supporting the development and regulation of the host immune system. However, knowledge of the impact that infections by GI helminths exert on the developing microbiota of juvenile hosts is, thus far, limited. This study investigates, for the first time, the associations between acute infections by GI helminths and the faecal microbial and metabolic profiles of a cohort of equine youngstock, prior to and following treatment with parasiticides (ivermectin). We observed that high versus low parasite burdens (measured via parasite egg counts in faecal samples) were associated with specific compositional alterations of the developing microbiome; in particular, the faecal microbiota of animals with heavy worm infection burdens was characterised by lower microbial richness, and alterations to the relative abundances of bacterial taxa with immune-modulatory functions. Amino acids and glucose were increased in faecal samples from the same cohort, which indicated the likely occurrence of intestinal malabsorption. These data support the hypothesis that GI helminth infections in young livestock are associated with significant alterations to the GI microbiota, which may impact on both metabolism and development of acquired immunity. This knowledge will direct future studies aimed to identify the long-term impact of infection-induced alterations of the GI microbiota in young livestock.

Fecal coagulase-negative staphylococci from horses, their species variability, and biofilm formation

The intestinal microbiota has enormous impact on the health and performance of horses. Staphylococci belong in the phylum Firmicutes, and their occurrence, especially of methicillin-resistant strains and species, has been reported in horses previously. Moreover, biofilm formation is one of the virulence factors; it has been not completely studied in fecal coagulase-negative staphylococci (CoNS) from horses. Therefore, this study was focused on biofilm formation by various species of fecal CoNS from horses because it has been never reported before. In addition, their antibiotic profile was tested. Horses (42) of various breeds from Slovakia/Poland were sampled. Variability in the species of CoNS was detected in feces of horses. Thirty-two strains were identified by using the MALDI-TOF system and classified into nine species and three subspecies of CoNS: Staphylococcus capitis, S. cohnii subsp. cohnii, S. cohnii subsp. urealyticus, S. cohnii subsp. casei, S. epidermidis, S. haemolyticus, S. pasteuri, S. sciuri, S. vitulinus, S. warneri, and S. xylosus. The most frequent species was S. vitulinus. Twenty-two strains showed high biofilm production; 10 strains showed low-grade biofilm production. The highest biofilm formation was measured in the species S. xylosus. Eleven strains (of 32) were methicillin-resistant; the others were susceptible to methicillin.

Antimicrobial Stewardship in Veterinary Medicine

While antimicrobial resistance is already a public health crisis in human medicine, therapeutic failure in veterinary medicine due to antimicrobial resistance remains relatively uncommon. However, there are many pathways by which antimicrobial resistance determinants can travel between animals and humans: by close contact, through the food chain, or indirectly via the environment. Antimicrobial stewardship describes measures that can help mitigate the public health crisis and preserve the effectiveness of available antimicrobial agents. Antimicrobial stewardship programs have been principally developed, implemented, and studied in human hospitals but are beginning to be adapted for other applications in human medicine. Key learning from the experiences of antimicrobial stewardship programs in human medicine are summarized in this article-guiding the development of a stewardship framework suitable for adaptation and use in both companion animal and livestock practice. The antimicrobial stewardship program for veterinary use integrates infection prevention and control together with approaches emphasizing avoidance of antimicrobial agents. The 5R framework of continuous improvement that is described recognizes the importance of executive support; highly motivated organizations and teams (responsibility); the need to review the starting position, set objectives, and determine means of measuring progress and success; and a critical focus on reducing, replacing, and refining the use of antimicrobial agents. Significant issues that are currently the focus of intensive research include improved detection and diagnosis of infections, refined dosing regimens that are simultaneously effective while not selecting resistance, searches for alternatives to antimicrobial agents, and development of improved vaccines to enhance immunity and reduce disease.

Probiotic supplementation in trained trotter horses: effect on blood clinical pathology data and urine metabolomic assessed in field

The attention of sports community toward probiotic supplementation as a way to promote exercise and training performance, together with good health, has increased in recent years. This has applied also to horses, with promising results. Here, for the first time, we tested a probiotic mix of several strains of live bacteria typically employed for humans to improve the training performance of Standardbred horses in athletic activity. To evaluate its effects on the horse performance, we measured lactate concentration in blood, a translational outcome largely employed for the purpose, combined with the study of hematological and biochemical parameters, together with urine from a metabolomics perspective. The results showed that the probiotic supplementation significantly reduced postexercise blood lactate concentration. The hematological and biochemical parameters, together with urine molecular profile, suggested that a likely mechanism underlying this positive effect was connected to a switch of energy source in muscle from carbohydrates to short-chain fatty acids. Three sulfur-containing molecules differently concentrated in urines in connection to probiotics administration suggested that such switch was linked to sulfur metabolism. NEW & NOTEWORTHY Probiotic supplementation could reduce postexercise blood lactate concentration in Standardbred horses in athletic activity. Blood parameters, together with urine molecular profile, suggest the mechanism underlying this positive effect is connected to a switch of energy source in muscle from carbohydrates to short-chain fatty acids. Sulfur-containing molecules found in urines in connection to probiotics administration suggested that such switch was linked to sulfur metabolism.

Alterations in Intestinal Permeability: The Role of the "Leaky Gut" in Health and Disease

All species, including horses, suffer from alterations that increase intestinal permeability. These alterations, also known as "leaky gut," may lead to severe disease as the normal intestinal barrier becomes compromised and can no longer protect against harmful luminal contents including microbial toxins and pathogens. Leaky gut results from a variety of conditions including physical stressors, decreased blood flow to the intestine, inflammatory disease, and pathogenic infections, among others. Several testing methods exist to diagnose these alterations in both a clinical and research setting. To date, most research has focused on regulation of the host immune response due to the wide variety of factors that can potentially influence the intestinal barrier. This article serves to review the normal intestinal barrier, measurement of barrier permeability, pathogenesis and main causes of altered permeability, and highlight potential alternative therapies of leaky gut in horses while relating what has been studied in other species. Conditions resulting in barrier dysfunction and leaky gut can be a major cause of decreased performance and also death in horses. A better understanding of the intestinal barrier in disease and ways to optimize the function of this barrier is vital to the long-term health and maintenance of these animals.

Probiotic isolates from unconventional sources: a review

The use of probiotics for human and animal health is continuously increasing. The probiotics used in humans commonly come from dairy foods, whereas the sources of probiotics used in animals are often the animals’ own digestive tracts. Increasingly, probiotics from sources other than milk products are being selected for use in people who are lactose intolerant. These sources are non-dairy fermented foods and beverages, non-dairy and non-fermented foods such as fresh fruits and vegetables, feces of breast-fed infants and human breast milk. The probiotics that are used in both humans and animals are selected in stages; after the initial isolation of the appropriate culture medium, the probiotics must meet important qualifications, including being non-pathogenic acid and bile-tolerant strains that possess the ability to act against pathogens in the gastrointestinal tract and the safety-enhancing property of not being able to transfer any antibiotic resistance genes to other bacteria. The final stages of selection involve the accurate identification of the probiotic species.

Equine faecal microbiota transplant: Current knowledge, proposed guidelines and future directions

While certainly not a novel concept, faecal microbiota transplant (FMT) has recently garnered renewed interest in veterinary medicine due to its remarkable success in treating recurrent Clostridium difficile infection (CDI) in man. There is a dearth of information on indications and efficacy of FMT for the treatment of gastrointestinal disorders in the horse; however, based on evidence in man and other veterinary species, and anecdotal reports in horses, FMT may be a useful treatment for selected cases of acute and chronic diarrhoea and inflammatory bowel disease (IBD) in the horse. In the absence of evidence, expert opinion is offered on case selection and FMT procedure. More research is needed to explore the efficacy, indications and optimal preparation, storage and delivery of FMT to horses.

The longitudinal effect of a multi-strain probiotic on the intestinal bacterial microbiota of neonatal foals

REASONS FOR PERFORMING THE STUDY

The microbiota plays a key role in health and disease. Probiotics are a potential way to therapeutically modify the intestinal microbiota and prevent disease.

OBJECTIVES

The aim of this study was to investigate the effects of probiotics on the bacterial microbiota of foals during and after administration.

STUDY DESIGN

Randomised placebo controlled field trial.

METHODS

Thirty-eight healthy neonatal foals enrolled in a previous study were selected. The foals had received a multi-strain probiotic (four Lactobacillus spp. 3-4 × 10³ colony-forming units (cfu)/g each, Bifidobacterium animalis spp. lactis, 1 × 10^3-4 cfu/g) or placebo once daily for 3 weeks. A total of 3 faecal samples were collected from each foal at 2-week intervals and assessed via metagenomic sequencing. The Wilcoxon test was used to compare data between treatment groups.

RESULTS

There were no changes on the phylum, order or class level between treatment groups at any age (all P>0.05) but some significant changes in relative abundance of families. Probiotic administration did not result in an increased relative abundance of lactobacilli or bifidobacteria at any age (Lactobacillus: P = 0.9, P = 0.1 and P = 0.2, Bifidobacterium: P = 0.3, P = 0.6 and P = 0.1 for Weeks 2, 4 and 6, respectively). Lactobacillus was enriched in the probiotic group at Week 6 on LEfSe analysis (linear discriminant analysis score 0.34, P = 0 .02). There was no effect on alpha diversity (all P>0.2) or community structure when parsimony and unifrac analysis were applied (all P>0.6).

CONCLUSIONS

There were limited effects of probiotic treatment on the bacterial microbiota of foals. The studied probiotic based on lactobacilli and bifidobacteria has a limited potential for therapeutic modification of the gastrointestinal microbiota.

Effect of a probiotic on prevention of diarrhea and Clostridium difficile and Clostridium perfringens shedding in foals

Background

Up to 60% of foals develop diarrhea within 6 months after birth. Preventive measures are limited but potentially probiotics could be used.

Objective

To evaluate the effect of a newly designed probiotic on the incidence of foal diarrhea in a randomized field trial.

Animals

Seventy‐two healthy neonatal foals.

Methods

Randomized, placebo‐controlled field trial. Foals were administered a placebo or probiotic for 3 weeks and monitored for an additional week. A total of 3 fecal samples were taken from each foal at biweekly intervals. Statistical modeling was applied for comparison of incidence and duration of diarrhea and fecal shedding of Clostridium perfringens and Clostridium difficile between treatment and age groups.

Results

The overall incidence of diarrhea was 41 of 72 (59%) and did not differ (P = 0.37) between treatment groups. Foals treated with probiotics were more likely to develop diarrhea requiring veterinary intervention (P = 0.007). Age had a significant effect on incidence of diarrhea (P < 0.001); foals 8–15 days old having the highest probability of developing diarrhea. Duration of diarrhea and soft feces were not significantly different between groups. The prevalence of C. perfringens shedding was 55% with no difference between treatment groups (P = 0.23). The prevalence of C. difficile shedding was 11%.

Conclusion and Clinical Importance

There was no benefit of administering a 3‐week course of probiotics, but potential adverse effects were noted. Whether the probiotics lacked a clinical effect, or the choice of strains or dose was inadequate, is unknown. Clostridial shedding was not influenced by probiotics despite in vitro activity of probiotics.