The Intestinal Microbiome in Dogs with Chronic Enteropathies and Cobalamin Deficiency or Normocobalaminemia-A Comparative Study.

Cobalamin deficiency is a common sequela of chronic enteropathies (CE) in dogs. Studies comparing the intestinal microbiome of CE dogs with cobalamin deficiency to those that are normocobalaminemic are lacking. Therefore, our aim was to describe the fecal microbiome in a prospective, comparative study evaluating 29 dogs with CE and cobalamin deficiency, 18 dogs with CE and normocobalaminemia, and 10 healthy control dogs. Dogs with cobalamin deficiency were also analyzed after oral or parenteral cobalamin supplementation. Overall microbiome composition (beta diversity) at baseline was significantly different in CE dogs with cobalamin deficiency when compared to those with normocobalaminemia (p = 0.001, R = 0.257) and to healthy controls (p = 0.001, R = 0.363). Abundances of Firmicutes and Actinobacteria were significantly increased (q = 0.010 and 0.049), while those of Bacteroidetes and Fusobacteria were significantly decreased (q = 0.002 and 0.014) in CE dogs with cobalamin deficiency when compared to healthy controls. Overall microbiome composition in follow-up samples remained significantly different after 3 months in both dogs receiving parenteral (R = 0.420, p = 0.013) or oral cobalamin supplementation (R = 0.251, p = 0.007). Because cobalamin supplementation, in combination with appropriate therapy, failed to restore the microbiome composition in the dogs in our study, cobalamin is unlikely to be the cause of those microbiome changes but rather an indicator of differences in underlying pathophysiology that do not influence clinical severity but result in a significant aggravation of dysbiosis.

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.

Effect of amoxicillin-clavulanic acid on clinical scores, intestinal microbiome, and amoxicillin-resistant Escherichia coli in dogs with uncomplicated acute diarrhea.

BACKGROUND: Despite limited evidence of efficacy, antibiotic treatment is still frequently prescribed in dogs with uncomplicated acute diarrhea (AD). OBJECTIVE: To assess whether amoxicillin-clavulanic acid has a clinical benefit, an effect on the fecal microbiome, and the proportion of amoxicillin-resistant Escherichia coli in dogs with AD. ANIMALS: Sixteen dogs with AD of <3 days duration. METHODS: Prospective, placebo-controlled, double-blinded study. Clinical scores were compared between client-owned dogs randomly assigned to an antibiotic (AG) or a placebo (PG) group. The intestinal microbiome was analyzed using quantitative PCR assays. Amoxicillin-resistant fecal E. coli were assessed semiquantitatively with microbiological methods. RESULTS: There was no difference in clinical recovery between treated dogs or controls (CADS index day 10: AG group median: 2 (range: 1-3; CI [1.4; 2.6]); PG group median: 1.6 (range: 1-3; CI [1.1; 2.4]); P > .99). All dogs gained normal clinical scores (CADS index ≤3) after 1 to 6 days (median 2 days) after presentation. There was no significant difference in the fecal dysbiosis index (during treatment: AG mean -2.6 (SD 3.0; CI [-5.1; 0.0]); PG mean -0.8 (SD 4.0; CI [-4.2; 2.5]; P > .99) or its bacterial taxa. The proportion of resistant fecal E. coli increased (to median: 100%; range: 35%-100%) during treatment with amoxicillin-clavulanic acid and was still increased (median: 10%; range 2%-67%) 3 weeks after treatment, both of which were significantly higher proportions than in the placebo group for both time points (during treatment AG median 100% versus PG median 0.2% (P < .001); after treatment AG median 10% versus PG median 0.0% (P = .002)). CONCLUSIONS AND CLINICAL IMPORTANCE: Our study suggests that treatment with amoxicillin-clavulanic acid confers no clinical benefit to dogs with AD, but predisposes the development of amoxicillin-resistant E. coli, which persist for as long as 3 weeks after treatment. These findings support international guideline recommendations that dogs with diarrhea should not be treated with antimicrobials unless there are signs of sepsis.

Impaired autophagy induces chronic atrophic pancreatitis in mice via sex- and nutrition-dependent processes.

BACKGROUND & AIMS: Little is known about the mechanisms of the progressive tissue destruction, inflammation, and fibrosis that occur during development of chronic pancreatitis. Autophagy is involved in multiple degenerative and inflammatory diseases, including pancreatitis, and requires the protein autophagy related 5 (ATG5). We created mice with defects in autophagy to determine its role in pancreatitis. METHODS: We created mice with pancreas-specific disruption of Atg5 (Ptf1aCreex1;Atg5F/F mice) and compared them to control mice. Pancreata were collected and histology, immunohistochemistry, transcriptome, and metabolome analyses were performed. ATG5-deficient mice were placed on diets containing 25% palm oil and compared with those on a standard diet. Another set of mice received the antioxidant N-acetylcysteine. Pancreatic tissues were collected from 8 patients with chronic pancreatitis (CP) and compared with pancreata from ATG5-deficient mice. RESULTS: Mice with pancreas-specific disruption of Atg5 developed atrophic CP, independent of ß-cell function; a greater proportion of male mice developed CP than female mice. Pancreata from ATG5-deficient mice had signs of inflammation, necrosis, acinar-to-ductal metaplasia, and acinar-cell hypertrophy; this led to tissue atrophy and degeneration. Based on transcriptome and metabolome analyses, ATG5-deficient mice produced higher levels of reactive oxygen species than control mice, and had insufficient activation of glutamate-dependent metabolism. Pancreata from these mice had reduced autophagy, increased levels of p62, and increases in endoplasmic reticulum stress and mitochondrial damage, compared with tissues from control mice; p62 signaling to Nqo1 and p53 was also activated. Dietary antioxidants, especially in combination with palm oil-derived fatty acids, blocked progression to CP and pancreatic acinar atrophy. Tissues from patients with CP had many histologic similarities to those from ATG5-deficient mice. CONCLUSIONS: Mice with pancreas-specific disruption of Atg5 develop a form of CP similar to that of humans. CP development appears to involve defects in autophagy, glutamate-dependent metabolism, and increased production of reactive oxygen species. These mice might be used to identify therapeutic targets for CP.

Carbohydrate-Free Peach (Prunus persica) and Plum (Prunus salicina) [corrected] Juice Affects Fecal Microbial Ecology in an Obese Animal Model.

BACKGROUND: Growing evidence shows the potential of nutritional interventions to treat obesity but most investigations have utilized non-digestible carbohydrates only. Peach and plum contain high amounts of polyphenols, compounds with demonstrated anti-obesity effects. The underlying process of successfully treating obesity using polyphenols may involve an alteration of the intestinal microbiota. However, this phenomenon is not well understood. METHODOLOGY/PRINCIPAL FINDINGS: Obese Zucker rats were assigned to three groups (peach, plum, and control, n = 10 each), wild-type group was named lean (n = 10). Carbohydrates in the fruit juices were eliminated using enzymatic hydrolysis. Fecal samples were obtained after 11 weeks of fruit or control juice administration. Real-time PCR and 454-pyrosequencing were used to evaluate changes in fecal microbiota. Over 1,500 different Operational Taxonomic Units at 97% similarity were detected in all rats. Several bacterial groups (e.g. Lactobacillus and members of Ruminococcacea) were found to be more abundant in the peach but especially in the plum group (plum juice contained 3 times more total polyphenolics compared to peach juice). Principal coordinate analysis based on Unifrac-based unweighted distance matrices revealed a distinct separation between the microbiota of control and treatment groups. These changes in fecal microbiota occurred simultaneously with differences in fecal short-chain acids concentrations between the control and treatment groups as well as a significant decrease in body weight in the plum group. CONCLUSIONS: This study suggests that consumption of carbohydrate-free peach and plum juice has the potential to modify fecal microbial ecology in an obese animal model. The separate contribution of polyphenols and non-polyphenols compounds (vitamins and minerals) to the observed changes is unknown.

Evaluation of the MYC_CANFA gene in Chinese Shar Peis with cobalamin deficiency.

BACKGROUND: A recent genome-wide scan using the canine minimal screening set 2 (MSS-2) showed that cobalamin deficiency appears to be hereditary in Chinese Shar Peis and is linked to the microsatellite markers DTR13.6 and REN13N11 on canine chromosome 13. OBJECTIVE: The goal of this study was to evaluate the MYC_CANFA gene, which is the closest known gene with a distance of approximately 0.06 megabases (Mb) to the microsatellite marker DTR13.6, for any mutations in this breed. METHODS: Microsatellite markers (Myc and G15987) for genotyping and primers for sequencing were used to evaluate the MYC_CANFA gene. The genotype and gene sequence were compared between cobalamin-deficient Shar Peis, Shar Peis with normal serum cobalamin concentrations, and the DNA sequences published as part of the Ensemble Genomic map. RESULTS: Neither the microsatellite markers (Myc and G15987) nor the sequences of the MYC_CANFA gene showed a significant difference among both groups of Shar Peis and the published canine DNA sequence. CONCLUSIONS: The data presented here suggest that cobalamin deficiency in Shar Peis is not related to any mutations of the MYC_CANFA gene according to the genotyping and sequencing results in this study. Further investigations are warranted to find a potential genomic locus in proximity to DTR13.6 and REN13N11 that shows mutations in cobalamin-deficient Shar Peis.

Exocrine pancreatic insufficiency in the cat.

Exocrine pancreatic insufficiency (EPI) is a syndrome caused by an insufficient amount of pancreatic digestive enzymes in the small intestine. Clinical signs most commonly reported in cats with EPI are weight loss, loose and voluminous stools, steatorrhea, polyphagia, and in some cases a greasy soiling of the hair coat in the perianal region. Serum feline trypsin-like immunoreactivity concentration is the diagnostic test of choice for the diagnosis of affected cats. Treatment of cats with EPI consists of enzyme supplementation with either a powdered pancreatic extract or raw pancreas. Most cats with EPI also have severely decreased serum cobalamin concentrations and may require lifelong parenteral cobalamin supplementation. Most cats respond well to therapy and can have a normal life expectancy and quality of life.

Association between serum cobalamin and methylmalonic acid concentrations in dogs.

The aim of this study was to evaluate the association between serum methylmalonic acid (MMA), a proposed marker of cellular cobalamin deficiency, and serum cobalamin concentrations in dogs. Serum samples from 555 dogs were grouped according to their serum cobalamin concentrations (<150 ng/L to 1000 ng/L). Additionally, serum samples were collected from 43 healthy dogs to calculate a reference interval for canine serum MMA. MMA was measured using a GC/MS method. Groups were compared using a Kruskal-Wallis test with Dunn's post test. Proportions of dogs above the upper limit of the reference interval were calculated and a χ2-test for trend was performed to evaluate the association between serum cobalamin and MMA concentrations. The reference interval for serum MMA was calculated to be 414.7-1192.5 nmol/L. Dogs with serum cobalamin concentrations <251 ng/L had significantly higher MMA concentrations (P<0.05) and the χ2-test for trend showed a trend for increasing serum MMA concentrations with decreasing serum cobalamin concentrations (P<0.0001). Additionally, a number of dogs with normal serum cobalamin concentrations had increased serum MMA concentrations, suggesting that some of these dogs may have cobalamin deficiency on a cellular level. Further studies are warranted to determine if these dogs should receive cobalamin supplementation.

Lipid metabolism and hyperlipidemia in dogs.

Lipid metabolism in dogs can be divided into exogenous and endogenous pathways and exhibits some unique characteristics compared to other species. Hyperlipidemia is common in dogs, and can be either primary or secondary to other diseases. Secondary hyperlipidemia is the most common form and can be a result of endocrine disorders, pancreatitis, cholestasis, protein-losing nephropathy, obesity, and high fat diets. Primary hyperlipidemia is less common and usually associated with certain breeds. Hypertriglyceridemia of Miniature Schnauzers is the most common type of primary hyperlipidemia in dogs in the United States, and appears to have a genetic basis although its etiology remains unknown. Possible complications of canine hyperlipidemia include pancreatitis, liver disease, atherosclerosis, ocular disease, and seizures. Management is achieved by administration of low fat diets with or without the administration of lipid-lowering agents such as omega-3 fatty acids, gemfibrozil, and niacin.

Pancreatic response in healthy dogs fed diets of various fat compositions.

OBJECTIVE: To indirectly assess the pancreatic response in healthy dogs that were fed diets of different fat compositions with or without supplemental pancreatic enzymes and medium-chain triglycerides (MCTs). ANIMALS: 10 healthy adult dogs. PROCEDURES: Dogs were fed 4 diets once in random order at 1-week intervals; food was withheld from the dogs for > or = 12 hours prior to the feeding of each diet. Diets A and B contained 16% and 5% crude fat, respectively; diet C was composed of diet A with pancreatic enzymes; and diet D was composed of diet B with pancreatic enzymes and MCTs. Serum canine trypsin-like immunoreactivity (cTLI) and canine pancreatic lipase immunoreactivity (cPLI) concentrations were measured before (0 hours) and at 1 to 2 and 6 hours after feeding. Serum gastrin concentration was measured at 0 hours and at 5 to 10 minutes and 1 to 2 hours after feeding. A gastrin assay validation study was performed to confirm accuracy of test results in dogs. Data were analyzed by use of a repeated-measures general ANOVA. RESULTS: Serum cTLI, cPLI, or gastrin concentrations in the dogs did not differ among the different diets fed, among dogs, or over time. When multiple comparisons were analyzed, diet D caused the least amount of measurable pancreatic response, although this difference was not significant. CONCLUSIONS AND CLINICAL RELEVANCE: Results did not indicate a significant effect of dietary fat content or addition of supplemental MCT oil or pancreatic enzymes in diets on serum cTLI, cPLI, or gastrin concentrations in healthy dogs.

Oral bleeding associated with pancreatic enzyme supplementation in three dogs with exocrine pancreatic insufficiency.

Three dogs with exocrine pancreatic insufficiency developed oral bleeding during treatment with pancreatic enzyme supplements. According to the owners of the dogs, bleeding from the oral cavity developed during or shortly after consumption of meals containing the pancreatic enzyme supplement. Oral bleeding stopped in all dogs when owners reduced the dose of the pancreatic enzyme supplement. In 2 dogs, the decrease in the dose of the pancreatic enzyme supplement did not affect fecal consistency. However, in the third dog, the decrease in dose led to a recurrence of clinical signs. Findings in these dogs suggest that high doses of pancreatic enzyme supplements can cause oral bleeding in dogs with pancreatic insufficiency, but that oral bleeding can be successfully managed by dose reduction in most dogs.