Dogs' Microbiome From Tip to Toe

Aerobic Vaginal Microflora in Gestational and Non-Gestational Bitches (Canis lupus familiaris)

The vaginal tract comprises commensal microorganisms, which play an essential role in the health of the reproductive tract. Any dysbiosis in the vaginal microenvironment may lead to severe urinary tract infections or even infertility. This study aimed to evaluate the aerobic bacterial flora isolated from vaginal samples from 100 lactating bitches in the antepartum period (n = 3), postpartum period (n = 80), and with Lactatio sine graviditate (n = 17). Before vaginal swabs, all the bitches went through a gynecology consult, along with milk and blood sampling. Standard microbiological techniques were used for bacterial isolation. Among the 100 vaginal samples analyzed, 82% had a positive microbiological outcome, while 18% were negative. The microbiologic profile listed 17 different genera. The main isolated bacterial families were Micrococcaceae, Staphylococcaceae, Morganellaceae, Bacillaceae, and Rhizobiaceae. At the same time, strains like Agrobacterium radiobacter, Ochrobactrum anthropi, Chromobacterium violaceum, Burkholderia mallei, Bacillus pumllus, or Staphylococcus xylosus were isolated for the first time from the vaginal secretion of lactating bitches. The microbiological data demonstrates that lactating bitches' vaginal discharge is heterogeneous and may be affected by coitus, sampling season, age, and reproductive status.

Microbiota insights into pet ownership and human health

The relationship between pet and owner has already been studied in several studies. Reviewing and summarizing studies on human and pet microbiota and their effects due to keeping pets is the purpose of the current study. Microbiota of the gut, oral cavity, and skin are unique to each individual, and this is also true of their pets (cats and dogs). Microbiota homeostasis is essential for the health of pets and their owners. Dysbiosis or imbalances in the microbiota can increase the risk of disorder progressions such as IBD or Clostridium difficile infections, among others. The microbial communities of humans change as a result of various factors, such as keeping pets. Pet owners frequently contact domestic dogs and cats, which affects their microbiota. As a result of keeping pets, the microbiota of different areas of the human body has changed, which has been associated with a decrease in pathogenic bacteria and an increase in beneficial bacteria.

Squid meal and shrimp hydrolysate as novel protein sources for dog food

The world's growing pet population is raising sustainability and environmental concerns for the petfood industry. Protein-rich marine by-products might contribute to mitigating negative environmental effects, decreasing waste, and improving economic efficiency. The present study evaluated two marine by-products, squid meal and shrimp hydrolysate, as novel protein sources for dog feeding. Along with the analysis of chemical composition and antioxidant activity, palatability was evaluated by comparing a commercial diet (basal diet) and diets with the inclusion of 150 g kg-1 of squid meal or shrimp hydrolysate using 12 Beagle dogs (2.2 ± 0.03 years). Two in vivo digestibility trials were conducted with six dogs, three experimental periods (10 days each) and three dietary inclusion levels (50, 100 and 150 g kg-1) of squid meal or shrimp hydrolysate in place of the basal diet to evaluate effects of inclusion level on apparent total tract digestibility (ATTD), metabolizable energy content, fecal characteristics, metabolites, and microbiota. Both protein sources presented higher protein and methionine contents than ingredients traditionally used in dog food formulation. Shrimp hydrolysate showed higher antioxidant activity than squid meal. First approach and taste were not affected by the inclusion of protein sources, but animals showed a preference for the basal diet. Effects on nutrient intake reflected the chemical composition of diets, and fecal output and characteristics were not affected by the increasing inclusion levels of both protein sources. The higher ATTD of dry matter, most nutrients and energy of diets with the inclusion of both by-products when compared to the basal diet, suggests their potential to be included in highly digestible diets for dogs. Although not affected by the inclusion level of protein sources, when compared to the basal diet, the inclusion of squid meal decreased butyrate concentration and shrimp hydrolysate increased all volatile fatty acids, except butyrate. Fecal microbiota was not affected by squid meal inclusion, whereas inclusion levels of shrimp hydrolysate significantly affected abundances of Oscillosperaceae (UCG-005), Firmicutes and Lactobacillus. Overall, results suggest that squid meal and shrimp hydrolysate constitute novel and promising protein sources for dog food, but further research is needed to fully evaluate their functional value.

Early life programming by diet can play a role in risk reduction of otitis in dogs

Introduction

Otitis in dogs is often chronic while local treatment primarily consists of flushing, antibiotics, and/or antifungals. We were interested in finding early life variables that associate with otitis later in life, preferably some that could be modified.

Methods

A cross-sectional hypothesis-driven study with longitudinal data was performed to search for associations between pre- and postnatal exposures, and the incidence of owner-reported otitis in dogs at over 1 year of age. The multivariate logistic regression analysis study included data from 3,064 dogs and explored 26 different early life variables at four early life stages: prenatal, neonatal, postnatal, and puppyhood. We compared two feeding patterns, a non-processed meat-based diet (NPMD, raw) and an ultra-processed carbohydrate-based diet (UPCD, dry).

Results

We report that eating a NPMD diet significantly decreased the risk of otitis later in life, while eating a UPCD diet significantly increased the risk. This was seen in different life stages of mother or puppy: The maternal diet during pregnancy (p=0.011) and the puppies' diet from 2 to 6 months of age (p=0.019) were both significantly associated with otitis incidence later in life, whereas the puppies' first solid diet, was associated in the same way, but did not reach significance (p=0.072). Also, analyzing food ratios showed that when puppies were consuming >25% of their food as NPMD it significantly decreased their incidence of otitis later in life, while a ratio of >75% UPCD in their diet significantly increased their risk of otitis. Also, if the dog was born in the current family, was exposed to sunlight for more than 1 hour daily, and was raised on a dirt floor during puppyhood, there was a lower risk of otitis development later in life.

Discussion

The findings only suggest causality, and further studies are required. However, we propose that veterinarians, breeders, and owners can impact otitis risk by modifying factors such as diet and environment.

Longitudinal examination of urine pH, specific gravity, protein, culture, and antimicrobial resistance profiles in healthy dogs

BACKGROUND

Urine is routinely evaluated in dogs to assess health. Reference ranges for many urine properties are well established, but the scope of variation in these properties over time within healthy dogs is not well characterized.

OBJECTIVES

Longitudinally characterize urine properties in healthy dogs over 3 months.

ANIMALS

Fourteen healthy client-owned dogs.

METHODS

In this prospective study, dogs were evaluated for health; then, mid-stream free-catch urine was collected from each dog at 12 timepoints over 3 months. Urine pH, urine specific gravity (USG), protein, cultures, and antimicrobial resistance profiles were assessed at each timepoint.

RESULTS

Urine pH varied within and between dogs over time (Friedman's test: within P = .03; between P < .005). However, USG, protein, and bacterial diversity of urine were consistent within dogs over time, and only varied between dogs (Kruskal-Wallis: between all P < .005). Antimicrobial resistant isolates were identified in 12 out of 14 dogs with 34 of 48 of the isolates demonstrating resistance to amoxicillin.

CONCLUSIONS AND CLINICAL IMPORTANCE

Urine pH should be assessed at multiple timepoints via pH meter before making clinical decisions. Mid-stream free-catch urine with high concentrations of bacteria (>105  CFU/mL) should not be considered the only indicator of urinary tract infection. Bacterial isolates from dogs in this study had widespread resistance to amoxicillin/oxacillin underscoring the need for antimicrobial stewardship.

Microbial associations and transfers across the One Health Triad effects on human and animal adiposity and temperament: a protocol for an observational pilot study

Introduction

It is known that humans and pet dogs harbor microbial communities that are important regulators of health and disease. Pet dogs have been shown to promote microbial exchange between members of a household, a process that may have lasting health implications. Infancy marks a unique period of development as environmental exploration and introduction to complementary foods occur. This may lead to greater opportunities for microbial transfer between pet dogs and human infants due to a more confined shared environment, similar means of mobility, greater physical contact, and increased frequency of shared foods. This human-animal bond has led to extensive research in the areas of childhood allergies and behavioral health; however, there is a paucity in the available literature that has evaluated how this unique ecological relationship may impact both human and animal health.

Methods

Infants who reside in a household with a pet dog will be recruited from the greater Phoenix metropolitan area for this longitudinal, observational pilot study and followed through the complementary feeding period. Infant and pet dog fecal, salivary, and skin samples, as well as environmental samples from feeding areas/surfaces and main indoor play areas from both infants and pet dogs will be collected through in-home visits before (~5 mos), during (~9 mos), and after (~12 mos) the complementary feeding (CF) period. Anthropometrics, temperament, and dietary habits of both infants and pet dogs along with assessment of the home condition will also be collected. Microbial comparisons between infant and pet dog samples and evaluation of microbial changes during the CF period will be evaluated. Further, we will assess relationships between microbial composition and adiposity and temperament of both infants and pet dogs.

Discussion

The proposed observational pilot study will advance the available science by exploring how microbial communities are associated and change between infants and pet dogs before, during, and after the CF period, a unique period of human growth and development. Findings from this study will provide insights into the impact these ecological relationships have on each other and how transfer across the One Health Triad impacts human and animal health.

Bacterial community associated with gingivitis and periodontitis in dogs

Periodontal disease is a chronic condition characterized by bacterial adhesion, followed by biofilm formation, and subsequently by an inflammatory process that progresses to gingivitis and later to periodontitis. The variations in the oral microbiota have been associated with the progression of this disease. This study evaluated the alteration of the cultivable oral microbiota in dogs with different oral health status. Thirty dogs were selected and divided into three groups: healthy, gingivitis, and periodontitis. The collected oral samples were seeded, and colonies with distinct phenotypic characteristics were isolated and classified using sequencing of the 16S rRNA gene. The DNA sequences were aligned, and a phylogenetic tree was constructed. Simpson's diversity index was calculated, and a dissimilarity matrix based on the Jaccard similarity index was used to plot a principal coordinate analysis. A total of 119 bacteria with different colony morphologies were isolated and classified into 4 phyla, 29 genera, and 45 species based on phylogenetic analysis. The results indicated an increase in bacteria belonging to the Proteobacteria phylum and a less extended decrease in Actinobacteria, Firmicutes, and Bacteroidetes phyla in dogs with periodontal disease (gingivitis and periodontitis) compared to healthy dogs. Representatives of the genera Neisseria sp., Corynebacterium sp., Pasteurella sp., and Moraxella sp. increased through the worsening of the periodontal disease, while Staphylococcus sp. decreased. All groups exhibited moderate to high levels of biodiversity index, and the plotted PCoA show a clear separation in the oral microbiome of dogs with periodontitis compared to dogs with gingivitis and the healthy group.

Effect of the Administration of a Lyophilised Faecal Capsules on the Intestinal Microbiome of Dogs: A Pilot Study

Faecal Microbiota Transplantation (FMT) is a promising strategy for modulating the gut microbiome. We aimed to assess the effect of the oral administration of capsules containing lyophilised faeces on dogs with diarrhoea for 2 months as well as evaluate their long-term influence on animals' faecal consistency and intestinal microbiome. This pilot study included five dogs: two used as controls and three with diarrhoea. Animals were evaluated for four months by performing a monthly faecal samples collection and physical examination, which included faecal consistency determination using the Bristol scale. The total number of viable bacteria present in the capsules was quantified and their bacterial composition was determined by 16S rRNA gene sequencing, which was also applied to the faecal samples. During the assay, no side effects were reported. Animals' faecal consistency improved and, after ending capsules administration, Bristol scale values remained stable in two of the three animals. The animals' microbiome gradually changed toward a composition associated with a balanced microbiota. After FMT, a slight shift was observed in its composition, but the capsules' influence remained evident during the 4-month period. Capsules administration seems to have a positive effect on the microbiota modulation; however, studies with more animals should be performed to confirm our observations.

Fecal microbiota of the synanthropic golden jackal (Canis aureus)

The golden jackal (Canis aureus), is a medium canid carnivore widespread throughout the Mediterranean region and expanding into Europe. This species thrives near human settlements and is implicated in zoonoses such as rabies. This study explores for the first time, the golden jackal fecal microbiota. We analyzed 111 fecal samples of wild golden jackals using 16S rRNA amplicon sequencing the connection of the microbiome to animal characteristics, burden of pathogens and geographic and climate characteristics. We further compared the fecal microbiota of the golden jackal to the black-backed jackal and domestic dog. We found that the golden jackal fecal microbiota is dominated by the phyla Bacteroidota, Fusobacteriota and Firmicutes. The golden jackal fecal microbiota was associated with different variables, including geographic region, age-class, exposure to rabies oral vaccine, fecal parasites and toxoplasmosis. A remarkable variation in the relative abundance of different taxa was also found associated with different variables, such as age-class. Linear discriminant analysis effect size (LEfSe) analysis found abundance of specific taxons in each region, Megasphaera genus in group 1, Megamonas genus in group 2 and Bacteroides coprocola species in group 3. We also found a different composition between the fecal microbiota of the golden jackal, blacked-backed jackal and the domestic dog. Furthermore, LEfSe analysis found abundance of Fusobacterium and Bacteroides genera in the golden jackal, Clostridia class in blacked-backed jackal and Megamonas genus in domestic dog. The golden jackal fecal microbiota is influenced by multiple factors including host traits and pathogen burden. The characterization of the microbiota of this thriving species may aid in mapping its spread and proximity to human settlements. Moreover, understanding the jackal microbiota could inform the study of potential animal and human health risks and inform control measures.

Insect-based diets (house crickets and mulberry silkworm pupae): A comparison of their effects on canine gut microbiota

Background and Aim

The gut microbiome plays an important role in the overall health and well-being of dogs, influencing various physiological processes such as metabolism, nutrient absorption, and immune function. Edible insects are a sustainable and nutritious alternative protein source attracting increasing attention as a potential component of animal feeds, including pet food. However, little is known about the effects of insect-based diets on the gut microbiota of dogs. This study aimed to examine the fecal microbiota of dogs fed a diet that substituted common protein sources (poultry meal) with the house cricket (Acheta domesticus [AD]) or mulberry silkworm pupae (Bombyx mori pupae [BMp]) at different levels.

Materials and Methods

Fifteen healthy adult mixed-breed dogs were systemically randomized and assigned into each block under a completed randomized block design into the following five experimental dietary groups: control diet, 10% AD, 20% AD, 7% BMp, or 14% BMp for 29 days. The amounts fed to the dogs were based on the daily energy requirement. Fecal samples were collected on days 14 and 29 and analyzed for bacterial community structure using 16S ribosomal ribonucleic acid gene sequencing.

Results

At the phylum and genus levels, microbiota and their diversity were generally relatively similar among all treatments. The diets containing insects did not significantly alter the major phyla in the gut microbiome of dogs (p > 0.05). A few significant changes were found in the relative abundance of bacterial genera, with the levels of Allobaculum and Turicibacter being reduced in dogs fed a higher level of BMp. In contrast, only a decrease in Turicibacter was found in dogs fed the lower level of AD than the control diet (p < 0.05). Corynebacterium and Lactobacillus levels in the dogs fed 14% BMp were significantly increased compared with those in the control group (p < 0.05).

Conclusion

These findings suggest that insect-based diets may slightly alter the gut microbiota of dogs. Further research is needed to fully understand the mechanisms by which insect-based diets influence the gut microbiota of dogs and the long-term potential health implications.

Effects of Softening Dry Food with Water on Stress Response, Intestinal Microbiome, and Metabolic Profile in Beagle Dogs

Softening dry food with water is believed to be more beneficial to the intestinal health and nutrients absorption of dogs by some owners, but there appears to be little scientific basis for this belief. Thus, this study aimed to compare feeding dry food (DF) and water-softened dry food (SDF) on stress response, intestinal microbiome, and metabolic profile in dogs. Twenty healthy 5-month-old beagle dogs were selected and divided into two groups according to their gender and body weight using a completely randomized block design. Both groups were fed the same basal diet, with one group fed DF and the other fed SDF. The trial lasted for 21 days. The apparent total tract digestibility (ATTD) of nutrients, inflammatory cytokines, stress hormones, heat shock protein-70 (HSP-70), fecal microbiota, short-chain fatty acids (SCFAs), branch-chain fatty acids (BCFAs), and metabolomics were measured. Results showed that there was no significant difference in body weight, ATTD, and SCFAs between the DF and SDF groups (p > 0.05), whereas feeding with SDF caused a significant increase in serum cortisol level (p < 0.05) and tended to have higher interleukin-2 (p = 0.062) and HSP-70 (p = 0.097) levels. Fecal 16S rRNA gene sequencing found that the SDF group had higher alpha diversity indices (p < 0.05). Furthermore, the SDF group had higher levels of Streptococcus, Enterococcus, and Escherichia_Shigella, and lower levels of Faecalibacterium (p < 0.05). Serum and fecal metabolomics further showed that feeding with SDF significantly influenced the purine metabolism, riboflavin metabolism, and arginine and proline metabolism (p < 0.05). Overall, feeding with SDF caused higher cortisol level and generated effects of higher intestinal microbial diversity in dogs, but it caused an increase in some pathogenic bacteria, which may result in intestinal microbiome disturbance and metabolic disorder in dogs. In conclusion, feeding with SDF did not provide digestive benefits but caused some stress and posed a potential threat to the intestinal health of dogs. Thus, SDF is not recommended in the feeding of dogs.

Characterization of the oral and fecal microbiota associated with atopic dermatitis in dogs selected from a purebred Shiba Inu colony

Atopic dermatitis (AD) is a chronic and relapsing multifactorial inflammatory skin disease that also affects dogs. The oral and gut microbiota are associated with many disorders, including allergy. Few studies have addressed the oral and gut microbiota in dogs, although the skin microbiota has been studied relatively well in these animals. Here, we studied the AD-associated oral and gut microbiota in 16 healthy and nine AD dogs from a purebred Shiba Inu colony. We found that the diversity of the oral microbiota was significantly different among the dogs, whereas no significant difference was observed in the gut microbiota. Moreover, a differential abundance analysis detected the Family_XIII_AD3011_group (Anaerovoracaceae) in the gut microbiota of AD dogs; however, no bacterial taxa were detected in the oral microbiota. Third, the comparison of the microbial co-occurrence patterns between AD and healthy dogs identified differential networks in which the bacteria in the oral microbiota that were most strongly associated with AD were related with human periodontitis, whereas those in the gut microbiota were related with dysbiosis and gut inflammation. These results suggest that AD can alter the oral and gut microbiota in dogs.

Effects of Saccharomyces boulardii Supplementation on Nutritional Status, Fecal Parameters, Microbiota, and Mycobiota in Breeding Adult Dogs

Simple Summary

The aim of this study was to evaluate the effect of the administration of Saccharomyces boulardii on the nutritional, immunological, inflammatory, stress status, and the gut composition in 25 healthy adult American Staffordshire Terrier dogs. Supplementation with S. boulardii significantly improved the intestinal status and induced a reduction of stress, a common condition affecting animals managed in a breeding environment.

Abstract

The aim of this study was to evaluate the effect of the administration of Saccharomyces boulardii on the nutritional, immunological, inflammatory, and stress status and on the composition of the gut microbiota and mycobiota in healthy adult dogs. A total of 25 American Staffordshire Terrier dogs were selected and randomly assigned to two groups: control (CTR, n = 12) and treated (TRT, n = 13) groups. No significant differences were found between the two groups regarding body weight, body condition score, and fecal score. No significant differences in microbiota/mycobiota, short chain fatty acids, indole/skatole, histamine, zonulin, or lactoferrin were detected. Indeed, supplementation with S. boulardii significantly decreased fecal calprotectin Immunoglobulin A, indicating an improvement in the gut well-being. Interestingly, fecal cortisol significantly decreased in dogs belonging to the TRT group compared to the CTR, suggesting both an improvement of the intestinal status and a reduction of stress, a common condition affecting animals managed in a breeding environment.

Antimicrobial Resistance in Companion Animals: A New Challenge for the One Health Approach in the European Union

Antimicrobial resistance (AMR) and the increase in multi-resistant bacteria are among the most important threats to public health worldwide, according to the World Health Organisation (WHO). Moreover, this issue is underpinned by the One Health perspective, due to the ability of AMR to be transmitted between animals and humans living in the same environment. Therefore, since 2014 different surveillance and control programmes have been established to control AMR in commensal and zoonotic bacteria in production animals. However, public health authorities' reports on AMR leave out companion animals, due to the lack of national programmes and data collection by countries. This missing information constitutes a serious public health concern due to the close contact between companion animals, humans and their surrounding environment. This absence of control and harmonisation between programmes in European countries leads to the ineffectiveness of antibiotics against common diseases. Thus, there is a pressing need to establish adequate surveillance and monitoring programmes for AMR in companion animals and further develop alternatives to antibiotic use in this sector, considering the impact this could have on the gut microbiota. In this context, the aim of this review is to evaluate the current control and epidemiological situations of AMR in companion animals in the European Union (EU), as well as the proposed alternatives to antibiotics.