Characterization and Functional Test of Canine Probiotics

Multi-functional properties of lactic acid bacteria strains derived from canine feces

Introduction

Probiotics, especially Lactic Acid Bacteria (LAB), can promote the health of host animals in a variety of ways, such as regulating intestinal flora and stimulating the host's immune system.

Methods

In this study, 206 LAB strains were isolated from 48 canine fecal samples. Eleven LAB strains were selected based on growth performance, acid and bile salt resistance. The 11 candidates underwent comprehensive evaluation for probiotic properties, including antipathogenic activity, adhesion, safety, antioxidant capacity, and metabolites.

Results

The results of the antipathogenic activity tests showed that 11 LAB strains exhibited strong inhibitory effect and co-aggregation ability against four target pathogens (E. coli, Staphylococcus aureus, Salmonella braenderup, and Pseudomonas aeruginosa). The results of the adhesion test showed that the 11 LAB strains had high cell surface hydrophobicity, self-aggregation ability, biofilm-forming ability and adhesion ability to the Caco-2 cells. Among them, Lactobacillus acidophilus (L177) showed strong activity in various adhesion experiments. Safety tests showed that 11 LAB strains are sensitive to most antibiotics, with L102, L171, and L177 having the highest sensitivity rate at 85.71%, and no hemolysis occurred in all strains. Antioxidant test results showed that all strains showed good H2O2 tolerance, high scavenging capacity for 1, 1-diphenyl-2-trinitrophenylhydrazine (DPPH) and hydroxyl (OH-). In addition, 11 LAB strains can produce high levels of metabolites including exopolysaccharide (EPS), γ-aminobutyric acid (GABA), and bile salt hydrolase (BSH).

Discussion

This study provides a thorough characterization of canine-derived LAB strains, highlighting their multifunctional potential as probiotics. The diverse capabilities of the strains make them promising candidates for canine dietary supplements, offering a holistic approach to canine health. Further research should validate their efficacy in vivo to ensure their practical application.

The Function of Probiotics and Prebiotics on Canine Intestinal Health and Their Evaluation Criteria

Maintaining homeostasis within the intestinal microbiota is imperative for assessing the health status of hosts, and dysbiosis within the intestinal microbiota is closely associated with canine intestinal diseases. In recent decades, the modulation of canine intestinal health through probiotics and prebiotics has emerged as a prominent area of investigation. Evidence indicates that probiotics and prebiotics play pivotal roles in regulating intestinal health by modulating the intestinal microbiota, fortifying the epithelial barrier, and enhancing intestinal immunity. This review consolidates literature on using probiotics and prebiotics for regulating microbiota homeostasis in canines, thereby furnishing references for prospective studies and formulating evaluation criteria.

Lactobacillus johnsonii CPN23 vis-à-vis Lactobacillus acidophilus NCDC15 Improves Gut Health, Intestinal Morphometry, and Histology in Weaned Wistar Rats

The present investigation was carried out with the aim to establish the comparative efficacy of a canine-sourced probiotic meant for canine feeding and a conventional dairy-sourced probiotic. For this purpose, canine-origin Lactobacillus johnsonii CPN23 and dairy-origin Lactobacillus acidophilus NCDC15 were evaluated for potential probiotics health benefits in the rat model. Forty-eight weaned Wistar rats enrolled in this experiment of 8 weeks were fed a basal diet and divided into three dietary treatments. Rats of group I enrolled as control (CON) were given MRS placebo at 1 mL/head/day, while rats of group II (LAJ) and III (LAC) were administered with overnight MRS broth grown-culture of L. johnsonii CPN23 and L. acidophilus NCDC15, respectively, at 1 mL/head/day (108 cfu/mL). The average daily gain and net gain in body weight were significantly higher (p < 0.05) in LAJ and LAC than in CON. Fecal and digesta biochemical attributes altered (p < 0.05) positively in response to both probiotics. Total fecal and pooled digesta SCFAs were higher (p < 0.05) in both LAJ and LAC than in CON. The microbial population in cecal and colonic digesta responded (p < 0.05) positively to both probiotics. The diameter of intestinal segments was higher (p < 005) in LAJ as compared to CON. The number and height of villi in jejunum tended to be higher in LAJ as compared to CON. The humoral immune response to sheep erythrocytes as well as chicken egg-white lysozyme was higher in LAJ as compared to CON. Overall, the results of the study have demonstrated the effectiveness of the canine-sourced L. johnsonii CPN23 as a potential probiotic, with a comparatively better response than the dairy-sourced L. acidophilus NCDC15. It could thus be recommended for use in feeding dogs to help augment their health.

Characterization of feline-originated probiotics Lactobacillus rhamnosus CACC612 and Bifidobacterium animalis subsp. lactis CACC789 and and evaluation of their host response

BACKGROUND

Probiotics are beneficial for animal health and new potential probiotics need to be characterized for their prospective use in improving animal health. In this study, 32 bacterial strains were isolated from a Norwegian forest cat (castrated, 12 years old) and a Persian cat (castrated, 10 years old), which were privately owned and had indoor access.

RESULTS

Lactobacillus rhamnosus CACC612 (CACC612) and Bifidobacterium animalis subsp. lactis CACC789 (CACC789) were selected as potential probiotics; characterization of the two strains showed equivalent acid tolerance, similar cell adhesion rates on the HT-29 monolayer cell line, and superior bile tolerance compared to Lactobacillus rhamnosus GG (LGG). Subsequently, they exhibited inhibitory effects against a broad spectrum of pathogenic bacteria, including E. coli (KCTC 2617), Salmonella Derby (NCCP 12,238), Salmonella Enteritidis (NCCP 14,546), Salmonella Typhimurium (NCCP 10,328), Clostridium difficile JCM 1296T. From evaluating host effects, the viability of the feline macrophage cell line (Fcwf-4) increased with the treatment of CACC612 or CACC789 (P < 0.05). The induced expression of immune-related genes such as IFN-γ, IL1β, IL2, IL4, and TNF-α by immune stimulation was significantly attenuated by the treatment of CACC612 or CACC789 (P < 0.05). When 52 clinical factors of sera from 21 healthy cats were analyzed using partial least squares discriminant analysis (PLS-DA), the animals were obviously clustered before and after feeding with CACC612 or CACC789. In addition, hemoglobin and mean corpuscular hemoglobin concentration (MCHC) significantly increased after CACC612 feeding (P < 0.05).

CONCLUSIONS

In this study, feline-originated probiotics were newly characterized and their potentially probiotic effects were evaluated. These results contribute to our understanding of the functional effects of feline-derived probiotics and support their industrial applications.

Prevalence of Pentatrichomonas hominis in foxes and raccoon dogs and changes in the gut microbiota of infected female foxes in the Hebei and Henan Provinces in China

Pentatrichomonas hominis (P. hominis) is a zoonotic parasite that affects a wide range of hosts, causing gastrointestinal diseases. The present study aimed to evaluate the prevalence of P. hominis among caged foxes and raccoon dogs and the effect of P. hominis on the gut microbiota in female foxes. A total of 893 fresh fecal samples were collected from the Hebei and Henan Provinces in China. P. hominis was screened based on 18S rRNA gene expression via nested PCR. The difference in the gut microbiota between nine P. hominis-positive and nine P. hominis-negative samples was investigated by 16S rRNA gene sequencing. The total prevalence of P. hominis infection in foxes and raccoon dogs was 31.7% (283/893). The prevalence rates of P. hominis infection were 28.2% (88/312) and 33.6% (195/581) in foxes and raccoon dogs, respectively. Phylogenetic analysis revealed that all P. hominis strains detected in foxes and raccoon dogs in the present study were the zoonotic genotype CC1. Moreover, compared with those in the P. hominis-negative group, the diversity of the gut microbiota in the P. hominis-positive group was lower, and the abundance of Firmicutes and the ratio of Firmicutes/Bacteroidetes (F/B) in the P. hominis-positive group were lower than those in the P. hominis-negative group. We speculate that these differences may be due to indigestion and diarrhea in infected female foxes. Overall, the present study evaluated the prevalence of P. hominis in foxes and raccoon dogs in the Henan and Hebei Provinces and revealed that P. hominis infection interrupted the diversity of the gut microbiota in female foxes.

Identification and evaluation of probiotic potential of Bifidobacterium breve AHC3 isolated from chicken intestines and its effect on necrotizing enterocolitis (NEC) in newborn SD rats

Necrotizing enterocolitis (NEC) is a severe intestinal disease of the newborn infants, associated with high morbidity and mortality. It has been reported that Bifidobacterium could protect the intestinal barrier function and reduce the risk of NEC. This study aimed to evaluate the probiotic potential of Bifidobacterium strains isolated from the chicken intestines and its effect on necrotizing enterocolitis in newborn SD rats. Out of 32 isolates, B. breve AHC3 not only exhibited excellent probiotic potential, including tolerance to artificial simulated gastric conditions, adhesion to HT-29 cells, antioxidant capacity and antibacterial activity, but also possessed reliable safety. Additionally, NEC model was established to further investigate the effect of B. breve AHC3 on necrotizing enterocolitis in newborn SD rats. It was illustrated that administration of B. breve AHC3 significantly not only reduced the incidence of NEC (from 81.25% to 34.38%) (P< 0.05), but also alleviated the severity of ileal injury (P< 0.05). Compared with NEC model, B. breve AHC3 could significantly decrease the level of proinflammatory factor TNF-α (P< 0.05) and increase the level of antiinflammatory factor IL-10 (P< 0.05) in the ileum of NEC rats. Through the intervention of B. breve AHC3, the gray value of inducible nitric oxide synthase (iNOS) in intestinal tissue of NEC rats was significantly reduced (P< 0.05). It was indicated that B. breve AHC3 exhibited prominent probiotic potential and reliable safety. In the neonatal SD rat model of NEC, B. breve AHC3 had an available protective effect on the intestinal injury of NEC, which might be related to reducing the inflammatory reaction in the ileum and inhibiting the expression of iNOS in intestinal tissue cells. B. breve AHC3 could be used as a potential treatment for human NEC.

Gut Probiotics and Health of Dogs and Cats: Benefits, Applications, and Underlying Mechanisms

Pets (mostly domestic dogs and cats) play an important role in the daily lives of humans and their health has attracted growing attention from pet owners. The intestinal microbiota, a complex microbial community with barrier-protective, nutritional, metabolic, and immunological functions, is integral to host health. Dysbiosis has been related to a variety of diseases in humans and animals. Probiotics have been used in functional foods and dietary supplements to modulate intestinal microbiota and promote host health, which has been introduced in pet dogs and cats in recent years. Various canine- and feline-derived probiotic strains have been isolated and characterized. The administration of probiotics has shown positive effects on the gut health and can alleviate some intestinal diseases and disorders in dogs and cats, although the underlying mechanisms are largely unresolved. In this review, we summarize the current knowledge on the benefits of probiotics and discuss their possible mechanisms in dogs and cats in order to provide new insights for the further development and application of probiotics in pets.

Complete genome sequence of Pediococcus acidilactici CACC 537 isolated from canine

Pedi coccus acidilactici CACC 537 was isolated from canine feces and reported to have probiotic properties. We aimed to characterize the potential probiotic properties of this strain by functional genomic analysis. Complete genome sequencing of P. acidilactici CACC 537 was performed using a PacBio RSII and Illumina platform, and contained one circular chromosome (2.0 Mb) with a 42% G + C content. The sequences were annotation revealed 1,897 protein-coding sequences, 15 rRNAs, and 56 tRNAs. It was determined that P. acidilactici CACC 537 genome carries genes known to be involved in the immune system, defense mechanisms, restriction-modification (R-M), and the CRISPR system. CACC 537 was shown to be beneficial in preventing pathogen infection during the fermentation process, help host immunity, and maintain intestinal health. These results provide for a comprehensive understanding of P. acidilactici and the development of industrial probiotic feed additives that can help improve host immunity and intestinal health.

Effects of hydrolyzed chicken liver on digestibility, fecal and urinary characteristics, and fecal metabolites of adult dogs

High-protein low-carbohydrate diets have been widely used for adult maintenance dogs, as well as in specific weight loss diets and maintenance programs. However, increasing dietary protein may increase undigested protein in the hindgut, modifying intestinal fermentation and fecal metabolite concentrations. The aim of this study was to evaluate the effects of protein source and concentration on apparent total tract digestibility (ATTD) of nutrients, metabolizable energy (ME), fecal and urinary characteristics, and fecal metabolites of dogs. Twelve healthy adult dogs were distributed into six treatments (n = 6 per diet) in a balanced incomplete Latin square design consisting of three periods of 30 days each. Six diets, varying in protein source [poultry byproduct meal (PBPM) and hydrolyzed chicken liver powder (HCLP)] and concentration [24, 32, and 40% crude protein (CP) on dry matter (DM) basis] were tested: PBPM24 (PBPM based diet with 24% CP); PBPM32 (PBPM with 32% CP); PBPM40 (PBPM with 40% CP); HCLP24 (HCLP based diet with 24% CP); HCLP32 (HCLP with 32% CP); HCLP40 (HCLP with 40% CP). The ATTD of CP was greater in dogs-fed HCLP and higher protein concentrations diets (P < 0.05). However, dogs-fed HCLP diets had lower ATTD of fat and carbohydrates, and ME (P < 0.05). Similarly, high-protein diets reduced the ATTD of DM, OM, fat, carbohydrates, and energy (P < 0.05). High-protein diets increased the daily fecal output and moisture (P = 0.004 and P < 0.05, respectively), as well as the fecal score (P < 0.0001), verified as soft, moist stools, but still within the ideal range. Fecal valerate concentration was greater in dogs-fed PBPM at 32% CP (P = 0.007). Fecal isobutyrate tended to increase in dogs-fed PBPM and high-protein diets (P < 0.10). Also, dogs-fed PBPM and high-protein diets had greater fecal concentrations of isovalerate, branched-chain fatty acids (BCFA), and ammonia (P < 0.05). Finally, the fecal lactate concentration increased in dogs-fed HCLP and high-protein diets (P < 0.05). The HCLP increased the ATTD of CP, being a highly digestible protein. Although the inclusion of HCLP slightly increased fecal score and moisture, it decreased the amount of fecal metabolites of protein fermentation ammonia and BCFA, both of which are associated with proteolytic fermentation in the colon.

Evaluation of the Anticancer and Probiotic Potential of Autochthonous (Wild) Lacticaseibacillus paracasei Strains from New Ecological Niches as a Possible Additive for Functional Dairy Foods

Probiotics such as Lactobacillus spp. could modulate the intestinal microbiota composition, supporting gastrointestinal tract barrier function and benefiting human health. To evaluate the anticancer and probiotic properties of potentially active autochthonous Lacticaseibacillus paracasei strains on proliferating and differentiated enterocytes, human colon adenocarcinoma cell line HT29 was used as a model. The lactic acid bacteria (LAB) were isolated from new ecological niches—mountain anthills populated by redwood ants (Formica rufa L.). Human colorectal adenocarcinoma cells (HT29, ATCC, HTB-38™) were treated for twenty-four hours with supernatants (SNs) derived from four strains of Lacticaseibacillus paracasei: P4, C8, C15 and M2.1. An MTT assay, alkaline phosphatase activity, IAP, Bax and Bcl-2 gene expression analysis (RT-qPCR) and the Bax/Bcl-2 ratio were evaluated. The MTT assay revealed that the observed effects varied among groups. However, 10% neutralized supernatants from P4, C8, C15 and M2.1 strains did not show cytotoxic effects. In contrast to non-differentiated cells, a significant (p < 0.001) rise in ALP activity in all treatments, with an average of 18%, was established in differentiated cells. The IAP expression was remarkably downregulated in the differentiated M2.1 group (p < 0.05) and upregulated in the non-differentiated P4 (p < 0.05) and M2.1 (p < 0.05) groups. The Bax/Bcl-2 quantity expression ratio in P4 was significantly (p < 0.05) upregulated in proliferating cancer cells, but in P4- and M2.1-differentiated cells these values were downregulated (p < 0.05). The obtained results indicate that the isolated L. paracasei strains possess anticancer and probiotic properties and could be used as additives for functional dairy foods and thus benefit human health.

Levilactobacillus brevis from carnivores can ameliorate hypercholesterolemia: in vitro and in vivo mechanistic evidence

AIMS

To explore the probiotic and hypocholesterolemic potential of two Levilactobacillus brevis strains of carnivore origin along with selected underlying mechanisms.

METHODS AND RESULTS

L. brevis MT950194 and L. brevis MW365351 were analyzed in vitro for oro-gastro-intestinal stress tolerance, cholesterol reduction, cholesterol adsorption (through scanning electron microscopy) and bile salt hydrolase (BSH) activity. Strains could survive (> 80%) in oro-gastro-intestinal conditions, reduce high amount of cholesterol (35% and 54%) from media containing bile salts (0.3%) as compared with Lactobacillus acidophilus ATCC4356 and presented least pathogenicity towards mammalian cells. Exopolysaccharide production, cell surface cholesterol adherence and BSH activity were witnessed as possible cholesterol lowering mechanisms. In in vivo experiment, the treatments of hypercholesterolemic rats with L. brevis MT950194, L. brevis MW365351 and their mixture led to significant (p < 0.05) reduction in serum and hepatic cholesterol, low density lipids, cholesterol ratio, liver steatosis, and size of adipocytes. It further ameliorated diet induced changes in hepatic enzymes.

CONCLUSIONS

L. brevis MT950194 and L. brevis MW365351 from carnivores have probiotic pharmacological potential and can reduce serum cholesterol through surface adherence and BSH production.

SIGNIFICANCE AND IMPACT OF STUDY

These strains may be utilized in treating hypercholesterolemia and production of low fat functional foods.

Prevalence and genetic diversity of Giardia duodenalis in pet dogs from Zhengzhou, central China and the association between gut microbiota and fecal characteristics during infection

As a common zoonotic intestinal parasite, Giardia duodenalis could infect humans and various mammals worldwide, including pet dogs, leading to giardiasis. This study detected the infection of G. duodenalis in asymptomatic pet dogs in Zhengzhou, and evaluated the possibility of zoonosis and the relationship between gut microbiota and fecal characteristics. We randomly collected 448 fresh fecal samples from Zhengzhou, and G. duodenalis was screened based on the beta-giardin (bg), glutamate dehydrogenase (gdh), and triose phosphate isomerase (tpi) genes. The difference of gut microbiota between five G. duodenalis-positive and five G. duodenalis-negative samples was investigated by 16S rRNA gene sequencing. The overall prevalence of G. duodenalis was 7.1% (32/448) based on bg, gdh, and tpi locus, two G. duodenalis assemblages (C = 13, D = 14) and five (15.6%) mixed infection (C + D) were identified. Moreover, compared with the G. duodenalis-negative group, the diversity of gut microbiota increased in G. duodenalis-positive group. The decrease of Lactobacillus spp. and considerable increase of Prevotella spp. were associated with the fecal characteristics. These results show that the transmission of zoonotic giardiasis between humans and pet dogs is rare in Zhengzhou, central China, and support the use of Lactobacillus spp. as a potential probiotic agent to improve intestinal health in dogs, or even humans, by treating G. duodenalis. Therefore, the public health significance of G. duodenalis to humans, companion animals, and the environment should be further evaluated from One Health perspective.

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Prevalence of G. duodenalis was 7.1% in pet dogs in Zhengzhou, central China.

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G. duodenalis assemblage D infection is associated to higher gut microbial diversity.

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The abundance of Prevotella and Lactobacillus may affect fecal characteristics.

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Lactobacillus may be used as a potential feed additive to treat giardiasis.

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Effective strategies should be taken to minimize the threat posed by G. duodenalis.

Compositional Quality and Possible Gastrointestinal Performance of Marketed Probiotic Supplements

The local pharmacies and shops are brimming with various probiotic products that herald a range of health benefits. The poor quality of probiotic products in both dosage and species is symptomatic of this multi-billion-dollar market making it difficult for consumers to single out reliable ones. This study aims to fill the potential gap in the labeling accuracy of probiotic products intended for human consumption. We describe a combinatorial approach using classical culture-dependent technique to quantify and molecular techniques (16 s rRNA gene sequencing, multilocus sequence, and ribotyping) for strain recognition of the microbial contents. The full gamut of probiotic characteristics including acid, bile and lysozyme tolerances, adhesiveness, anti-pathogenicity, and degree of safeness were performed. Their capacity to endure gastro-intestinal (GIT) stresses and select drugs was assessed in vitro. Our results forced us to declare that the local probiotic market is essentially unregulated. Almost none of the probiotic products tested met the label claim. Some (11%) have no viable cells, and a quarter (27%) showing significant inter-batch variation. A lower microbial count was typical with undesirables constituting a quarter of the total (~ 27%). Half of the products contained antibiotic-resistant strains; the unregulated use of these probiotics carries the risk of spreading antibiotic resistance to gut pathobionts. Poor tolerance to gut conditions and mediocre functionalism make the case worse. The current regulatory systems do not take this discrepancy into account. We recommend an evidence-based regular market surveillance of marketed probiotics to ensure the authenticity of the claims and product effectiveness.

Complete genome sequence of Bacillus coagulans CACC834 isolated from canine

Bacillus coagulans CACC 834 was isolated from canine feces, and its potential probiotic properties were characterized by functional genome analysis. Whole-genome sequencing of B. coagulans CACC 834 was performed using the PacBio RSII platforms. The complete genome assembly consisted of one circular chromosome (3.1 Mb) with guanine (G) + cytosine (C) content of 47.1%. Annotation revealed 3,181 protein-coding sequences (CDSs), 30 rRNAs, and 83 tRNAs. Gene associated 11% of the genes were involved in replication, recombination, and repair. We also annotated various stress-related, acid resistance, bile salt resistance and adhesion-related domains in this strain, which likely provide support in exerting probiotic action by survival under gastrointestinal tract. These results add to our comprehensive understanding of B. coagulans and suggest potential mammal-related industrial applications.

Antioxidant and Anti-Inflammatory Effect and Probiotic Properties of Lactic Acid Bacteria Isolated from Canine and Feline Feces

Oxidative stress is a phenomenon caused by an imbalance between the production of reactive oxygen species and antioxidant defenses. It plays an important role in numerous disease states, including chronic kidney disease, neurological disorders, cardiovascular diseases, diabetes, and cancer. Lactic acid bacteria (LAB) are known to have prominent antioxidant properties. Therefore, this study aimed to measure the antioxidant activity and anti-inflammatory potential of LAB isolated from animals for the efficient use of probiotics with host specificity. Antioxidant activity measurements of sixteen strains revealed that ABTS radical scavenging activities ranged from 26.3 to 57.4%, and DPPH free radical scavenging activities ranged from 4.7 to 13.5%. Based on the antioxidant activity assessment, five strains (Enterococcus faecium MG9003(YH9003), Enterococcus faecium MG9007(YH9007), Lactobacillus reuteri MG9012(YH9012), Lactobacillus fermentum MG9014(YH9014), and Pediococcus pentosaceus MG9015(YH9015)) were selected with the consideration of fermentation productivity (>1 × 10⁹ CFU/g). The selected strains exhibited nitric oxide inhibition and inhibited inducible nitric oxide synthase and cyclooxygenase expression. Furthermore, probiotic properties, including intestinal adhesion and stability, were identified. Our results show that the selected animal-derived strains can be effective probiotic candidates for potential effects on animal hosts.