Clostridium Hiranonis, a Bile Acid 7α-Dehydroxylating Bacterium in Dogs

Bile acids (BAs) are bioactive molecules that are crucial for the absorption of fat-soluble nutrients and regulation of host metabolism, including glucose, lipid, and energy homeostasis. BAs are synthesized in the liver and are further metabolized by microbiota in the gut. Previous studies have shown that an alteration of gastrointestinal microbiota, referred to as dysbiosis, can alter the bile acid profiles. This aim of this project was to identify and characterize Clostridium hiranonis, a bile acid 7α-dehydroxylating bacterium from canine feces, and to study the association between C. hiranonis and secondary bile acids (SBAs). Firstly, this study evaluated the fecal microbiome of dogs with exocrine pancreatic insufficiency (EPI) based on 16S rRNA sequencing. The fecal microbiota of dogs with EPI was different when compared to healthy control dogs. In dogs with EPI, the bacterial families, Lachnospiraceae and Ruminococcaceae were decreased, while Lactobacillus, Bifidobacterium, and Enterococcus were increased in dogs with EPI. At the species level, Blautia producta, Clostridium hiranonis, Faecalibacterium prausnitzii, Ruminoccocus gnavus, and Collinsella stercoris were decreased in dogs with EPI. Secondly, this study isolated, identified, and characterized C. hiranonis from canine feces. The canine isolates were similar to the reference strain C. hiranonis DSM 13275 based on morphological, biochemical, and fatty acid profiles. Based on whole genome sequencing results, these isolates possess genes for the enzymes choloylglycine hydrolase, and bile acid 7α- dehydratase, which are essential for deconjugation and bile acid 7α-dehydroxylation of primary bile acids. Finally, this study examined the correlation between C. hiranonis and SBAs in canine fecal samples. Results show that C. hiranonis and SBA concentrations are significantly correlated in canine feces. The ROC analysis showed that the fecal abundance of C. hiranonis can be used to discern between normal and low fecal SBAs with a sensitivity of 88% and specificity of 90% in dogs. In conclusion, this is the first study to isolate and characterize C. hiranonis from canine feces and to find a significant correlation between SBA concentrations and abundance of C. hiranonis in canine feces

Weaned beef calves fed selenium-biofortified alfalfa hay have an enriched nasal microbiota compared with healthy controls

Selenium (Se) is an essential trace mineral important for immune function and overall health of cattle. The nasopharyngeal microbiota in cattle plays an important role in overall respiratory health, especially when stresses associated with weaning, transport, and adaptation to a feedlot affect the normal respiratory defenses. Recent evidence suggests that cattle diagnosed with bovine respiratory disease complex have significantly less bacterial diversity. The objective of this study was to determine whether feeding weaned beef calves Se-enriched alfalfa (Medicago sativa) hay for 9 weeks in a preconditioning program prior to entering the feedlot alters nasal microbiota. Recently weaned beef calves (n = 45) were blocked by sex and body weight, randomly assigned to 3 treatment groups with 3 pens of 5 calves per treatment group, and fed an alfalfa hay based diet for 9 weeks. Alfalfa hay was harvested from fields fertilized with sodium selenate at a rate of 0, 45.0 or 89.9 g Se/ha. Blood samples were collected biweekly and analyzed for whole-blood Se concentrations. Nasal swabs were collected during week 9 from one or two calves from each pen (total n = 16). Calculated Se intake from dietary sources was 3.0, 15.6, and 32.2 mg Se/head/day for calves consuming alfalfa hay with Se concentrations of 0.34 to 2.42 and 5.17 mg Se/kg dry matter, respectively. Whole-blood Se concentrations after 8 weeks of feeding Se-fertilized alfalfa hay were dependent upon Se-application rates (0, 45.0, or 89.9 g Se/ha) and were 155, 345, and 504 ng/mL (PLinear < 0.0001). Microbial DNA was extracted from nasal swabs and amplified and sequenced. Alpha rarefaction curves comparing the species richness (observed OTUs) and overall diversity (Chao1, Observed OTU, and Shannon index) between calves fed selenium-biofortified alfalfa hay compared with control calves showed that Se-supplementation tended to be associated with an enriched nasal microbiota. ANOSIM of unweighted UniFrac distances showed that calves fed high Se-biofortified alfalfa hay clustered separately when compared with control calves in the PCoA plot (R = 0.216, P = 0.04). The bacterial orders Lactobacillales and Flavobacteriales were increased in healthy control calves compared with Clostridiales and Bacteroidales being increased in calves fed Se-biofortified alfalfa hay. Although there were strong trends, no significant differences were noted for any of the bacterial taxa. Based upon these findings, we suggest that weaned beef calves fed Se-biofortified hay tend to have an enriched nasal microbiota. Feeding Se-biofortified alfalfa hay to weaned beef calves prior to entering the feedlot is a strategy for increasing nasopharyngeal microbial diversity

Weaned beef calves fed selenium-biofortified alfalfa hay have an enriched nasal microbiota compared with healthy controls

Selenium (Se) is an essential trace mineral important for immune function and overall health of cattle. The nasopharyngeal microbiota in cattle plays an important role in overall respiratory health, especially when stresses associated with weaning, transport, and adaptation to a feedlot affect the normal respiratory defenses. Recent evidence suggests that cattle diagnosed with bovine respiratory disease complex have significantly less bacterial diversity. The objective of this study was to determine whether feeding weaned beef calves Se-enriched alfalfa (Medicago sativa) hay for 9 weeks in a preconditioning program prior to entering the feedlot alters nasal microbiota. Recently weaned beef calves (n = 45) were blocked by sex and body weight, randomly assigned to 3 treatment groups with 3 pens of 5 calves per treatment group, and fed an alfalfa hay based diet for 9 weeks. Alfalfa hay was harvested from fields fertilized with sodium selenate at a rate of 0, 45.0 or 89.9 g Se/ha. Blood samples were collected biweekly and analyzed for whole-blood Se concentrations. Nasal swabs were collected during week 9 from one or two calves from each pen (total n = 16). Calculated Se intake from dietary sources was 3.0, 15.6, and 32.2 mg Se/head/day for calves consuming alfalfa hay with Se concentrations of 0.34 to 2.42 and 5.17 mg Se/kg dry matter, respectively. Whole-blood Se concentrations after 8 weeks of feeding Se-fertilized alfalfa hay were dependent upon Se-application rates (0, 45.0, or 89.9 g Se/ha) and were 155, 345, and 504 ng/mL (PLinear < 0.0001). Microbial DNA was extracted from nasal swabs and amplified and sequenced. Alpha rarefaction curves comparing the species richness (observed OTUs) and overall diversity (Chao1, Observed OTU, and Shannon index) between calves fed selenium-biofortified alfalfa hay compared with control calves showed that Se-supplementation tended to be associated with an enriched nasal microbiota. ANOSIM of unweighted UniFrac distances showed that calves fed high Se-biofortified alfalfa hay clustered separately when compared with control calves in the PCoA plot (R = 0.216, P = 0.04). The bacterial orders Lactobacillales and Flavobacteriales were increased in healthy control calves compared with Clostridiales and Bacteroidales being increased in calves fed Se-biofortified alfalfa hay. Although there were strong trends, no significant differences were noted for any of the bacterial taxa. Based upon these findings, we suggest that weaned beef calves fed Se-biofortified hay tend to have an enriched nasal microbiota. Feeding Se-biofortified alfalfa hay to weaned beef calves prior to entering the feedlot is a strategy for increasing nasopharyngeal microbial diversity

Fecal Microbial and Metabolic Profiles in Dogs With Acute Diarrhea Receiving Either Fecal Microbiota Transplantation or Oral Metronidazole

The aim was to characterize differences in fecal consistency, and fecal microbiota and metabolome profiles in dogs with acute diarrhea (AD) treated with either fecal microbiota transplantation as enema (FMT;n = 11) or oral metronidazole (MET;n = 7) for 7 days. On days 0, 7, and 28 fecal samples were obtained. Fecal samples from healthy dogs (HC;n = 14) were used for comparison. Samples were analyzed by the previously validated qPCR based canine Dysbiosis Index (DI;increased values indicate microbiota dysbiosis) and 16S rRNA gene sequencing. The fecal metabolome was analyzed using a previously validated targeted canine assay for fecal unconjugated bile acids, and untargeted metabolomics. Fecal consistency improved significantly in dogs treated with FMT and MET by day 7 and day 28 (p < 0.01) compared to day 0. However, on day 28 fecal consistency was significantly better in FMT compared to MET (p = 0.040). At day 0, dogs with AD had an altered microbiota indicated by significantly increased DI, decreased alpha-diversity, and altered beta-diversity. In the FMT group, the DI decreased over time, while MET led to a significant increase in the dysbiosis index at day 7 and 28 compared to FMT. Sequencing data revealed that in FMT microbial diversity and beta-diversity was similar to HC at day 28, while in MET these parameters were still significantly different from HC. In dogs treated with FMT, a decrease in cholic acid and the percentage of primary bile acids was observed, whereas treatment with metronidazole led to an increase in cholic acid at day 7 and an increase in percentage of primary bile acids over time. Based on untargeted metabolomics, dogs with AD had an altered fecal metabolome compared to HC. Dogs treated with FMT clustered closer to HC at day 28, while dogs treated with MET did not. In this pilot study, dogs with AD had significant differences in fecal microbiota and metabolome profiles. Dogs treated with MET still had altered microbial and metabolic profiles at day 28 compared to dogs treated with FMT or healthy dogs

Faecal Microbiota of Cats with Insulin-Treated Diabetes Mellitus

Microorganisms within the gastrointestinal tract significantly influence metabolic processes within their mammalian host, and recently several groups have sought to characterise the gastrointestinal microbiota of individuals affected by metabolic disease. Differences in the composition of the gastrointestinal microbiota have been reported in mouse models of type 2 diabetes mellitus, as well as in human patients. Diabetes mellitus in cats has many similarities to type 2 diabetes in humans. No studies of the gastrointestinal microbiota of diabetic cats have been previously published. The objectives of this study were to compare the composition of the faecal microbiota of diabetic and non-diabetic cats, and secondarily to determine if host signalment and dietary factors influence the composition of the faecal microbiota in cats. Faecal samples were collected from insulin-treated diabetic and non-diabetic cats, and Illumina sequencing of the 16S rRNA gene and quantitative PCR were performed on each sample. ANOSIM based on the unweighted UniFrac distance metric identified no difference in the composition of the faecal microbiota between diabetic and non-diabetic cats, and no significant differences in the proportions of dominant bacteria by phylum, class, order, family or genus as determined by 16S rRNA gene sequencing were identified between diabetic and non-diabetic cats. qPCR identified a decrease in Faecalibacterium spp. in cats aged over ten years. Cat breed or gender, dietary carbohydrate, protein or fat content, and dietary formulation (wet versus dry food) did not affect the composition of the faecal microbiota. In conclusion, the composition of the faecal microbiota was not altered by the presence of diabetes mellitus in cats. Additional studies that compare the functional products of the microbiota in diabetic and non-diabetic cats are warranted to further investigate the potential impact of the gastrointestinal microbiota on metabolic diseases such as diabetes mellitus in cats

Clostridium Hiranonis, a Bile Acid 7α-Dehydroxylating Bacterium in Dogs

Bile acids (BAs) are bioactive molecules that are crucial for the absorption of fat-soluble nutrients and regulation of host metabolism, including glucose, lipid, and energy homeostasis. BAs are synthesized in the liver and are further metabolized by microbiota in the gut. Previous studies have shown that an alteration of gastrointestinal microbiota, referred to as dysbiosis, can alter the bile acid profiles. This aim of this project was to identify and characterize Clostridium hiranonis, a bile acid 7α-dehydroxylating bacterium from canine feces, and to study the association between C. hiranonis and secondary bile acids (SBAs). Firstly, this study evaluated the fecal microbiome of dogs with exocrine pancreatic insufficiency (EPI) based on 16S rRNA sequencing. The fecal microbiota of dogs with EPI was different when compared to healthy control dogs. In dogs with EPI, the bacterial families, Lachnospiraceae and Ruminococcaceae were decreased, while Lactobacillus, Bifidobacterium, and Enterococcus were increased in dogs with EPI. At the species level, Blautia producta, Clostridium hiranonis, Faecalibacterium prausnitzii, Ruminoccocus gnavus, and Collinsella stercoris were decreased in dogs with EPI. Secondly, this study isolated, identified, and characterized C. hiranonis from canine feces. The canine isolates were similar to the reference strain C. hiranonis DSM 13275 based on morphological, biochemical, and fatty acid profiles. Based on whole genome sequencing results, these isolates possess genes for the enzymes choloylglycine hydrolase, and bile acid 7α- dehydratase, which are essential for deconjugation and bile acid 7α-dehydroxylation of primary bile acids. Finally, this study examined the correlation between C. hiranonis and SBAs in canine fecal samples. Results show that C. hiranonis and SBA concentrations are significantly correlated in canine feces. The ROC analysis showed that the fecal abundance of C. hiranonis can be used to discern between normal and low fecal SBAs with a sensitivity of 88% and specificity of 90% in dogs. In conclusion, this is the first study to isolate and characterize C. hiranonis from canine feces and to find a significant correlation between SBA concentrations and abundance of C. hiranonis in canine feces

Supranutritional Selenium-Yeast Supplementation of Beef Cows during the Last Trimester of Pregnancy Results in Higher Whole-Blood Selenium Concentrations in Their Calves at Weaning, but Not Enough to Improve Nasal Microbial Diversity

We previously reported that feeding Se-biofortified alfalfa hay to weaned beef calves in a preconditioning program increases whole-blood Se (WB-Se) concentrations and nasal microbiome abundance and diversity during the preconditioning period, decreases morbidity and mortality during the feedlot period, and increases carcass weight and quality at slaughter. The objective of the current study was to see whether similar improvements can be achieved through Se supplementation of dams during various pregnancy trimesters. In a two-year experimental study, 80 Angus-cross cows received once-weekly Se-yeast boluses containing 105 mg of Se, during either the first (TR-1), second (TR-2), or third (TR-3) pregnancy trimester, or were not bolused (CTR). Whole-blood Se concentrations were higher from CTR, to TR-1, to TR-2, and to TR-3 in newborn calves (all p &lt; 0.01). At weaning, only calves from TR-3 mothers had higher WB-Se concentrations compared with calves from CTR mothers (p = 0.02), and no significant differences in nasal microbiome abundance and diversity or nasal microbiota were observed. In the feedlot period, morbidity was low, and no differences were observed. At slaughter, no differences in carcass weight and quality were observed. In conclusion, Se supplementation of pregnant cows is effective for increasing WB-Se concentration of newborn calves, and the increase can be sustained until weaning for calves born to TR-3 dams. However, the increase in WB-Se concentrations is small and does not result in beneficial changes in the nasal microbiome. Thus, calves should be fed Se-biofortified forages again at weaning in a preconditioning program in order to diversify the nasal microbiome prior to entering the feedlot

Linear discriminant analysis of KEGG pathways encoded by the nasal microbiota and their associations with dietary Se treatment¹.

<p>Only a LDA score of >2.5 is shown.</p

Characterization of the nasal and oral microbiota of detection dogs

<div><p>Little is known about physiological factors that affect the sense of olfaction in dogs. The objectives of this study were to describe the canine nasal and oral microbiota in detection dogs. We sought to determine the bacterial composition of the nasal and oral microbiota of a diverse population of detection canines. Nasal and oral swabs were collected from healthy dogs (n = 81) from four locations—Alabama, Georgia, California, and Texas. Nasal and oral swabs were also collected from a second cohort of detection canines belonging to three different detection job categories: explosive detection dogs (SP-E; n = 22), patrol and narcotics detection dogs (P-NDD; n = 15), and vapor wake dogs (VWD-E; n = 9). To understand if the nasal and oral microbiota of detection canines were variable, sample collection was repeated after 7 weeks in a subset of dogs. DNA was extracted from the swabs and used for 454-pyrosequencing of the16S rRNA genes. Nasal samples had a significantly lower diversity than oral samples (<i>P</i><0.01). Actinobacteria and Proteobacteria were higher in nasal samples, while Bacteroidetes, Firmicutes, Fusobacteria, and Tenericutes were higher in oral samples. Bacterial diversity was not significantly different based on the detection job. No significant difference in beta diversity was observed in the nasal samples based on the detection job. In oral samples, however, ANOSIM suggested a significant difference in bacterial communities based on job category albeit with a small effect size (R = 0.1079, <i>P</i> = 0.02). Analysis of the composition of bacterial communities using LEfSe showed that within the nasal samples, <i>Cardiobacterium</i> and <i>Riemerella</i> were higher in VWD-E dogs, and <i>Sphingobacterium</i> was higher in the P-NDD group. In the oral samples <i>Enterococcus</i> and <i>Capnocytophaga</i> were higher in the P-NDD group. <i>Gemella</i> and <i>Aggregatibacter</i> were higher in S-PE, and <i>Pigmentiphaga</i>, <i>Chryseobacterium</i>, <i>Parabacteroides</i> amongst others were higher within the VWD-E group. Our initial data also shows that there is a temporal variation in alpha diversity in nasal samples in detection canines.</p></div

Relative abundance of the most prevalent bacterial phyla identified in the nasal samples of randomly chosen healthy control calves (n = 5) and calves fed either medium (n = 6) or high (n = 5) Se-enriched alfalfa hay for 8 weeks.

<p>Alfalfa hay was harvested from fields with no Se fertilization (control) or from fields fertilized with sodium-selenate at application rates of 45.0 (medium) or 89.9 (high) g Se/ha.</p