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Objectives Previous studies have identified various bacterial taxa that are altered in cats with chronic enteropathies (CE) vs healthy cats. Therefore, the aim of this study was to develop a targeted quantitative molecular method to evaluate the fecal microbiota of cats. Methods Fecal samples from 80 client-owned healthy cats and 68 cats with CE were retrospectively evaluated. A panel of quantitative PCR (qPCR) assays was used to measure the fecal abundance of total bacteria and seven bacterial taxa: Bacteroides, Bifidobacterium, Clostridium hiranonis, Escherichia coli, Faecalibacterium, Streptococcus and Turicibacter. The nearest centroid classifier algorithm was used to calculate a dysbiosis index (DI) based on these qPCR abundances. Results The abundances of total bacteria, Bacteroides, Bifidobacterium, C hiranonis, Faecalibacterium and Turicibacter were significantly decreased, while those of E coli and Streptococcus were significantly increased in cats with CE ( P <0.027 for all). The DI in cats with CE was significantly higher compared with healthy cats ( P <0.001). When the cut-off value of the DI was set at 0, it provided 77% (95% confidence interval [CI] 66–85) sensitivity and 96% (95% CI 89–99) specificity to differentiate the microbiota of cats with CE from those of healthy cats. Fifty-two of 68 cats with CE had a DI >0. Conclusions and relevance A qPCR-based DI for assessing the fecal microbiota of cats was established. The results showed that a large proportion of cats with CE had an altered fecal microbiota as evidenced by an increased DI. Prospective studies are warranted to evaluate the utility of this assay for clinical assessment of feline CE.

Potential synergism between florfenicol (FF) and thiamphenicol (TAP) was investigated for in vitro efficacy against Actinobacillus pleuropneumoniae and/or Pasteurella multocida as well as in vivo efficacy in swine. Among isolates of A. pleuropneumoniae (n = 58) and P. multocida (n = 79) from pigs in Taiwan that were tested, high percentages showed resistance to FF (52 and 53%, respectively) and TAP (57 and 53%, respectively). Checkerboard microdilution assay indicated that synergism [fractional inhibitory concentration index (FICI) ≤ 0.5] was detected in 17% of A. pleuropneumoniae (all serovar 1) and 24% of P. multocida isolates. After reconfirming the strains showing FICI ≤ 0.625 with time kill assay, the synergism increased to around 32% against both bacteria and the number could further increase to 40% against resistant A. pleuropneumoniae and 65% against susceptible P. multocida isolates. A challenge-treatment trial in pigs with P. multocida showed that the FF + TAP dosage at ratios correspondent to their MIC deduction was equally effective to the recommended dosages. Further on the combination, the resistant mutation frequency is very low when A. pleuropneumoniae is grown with FF + TAP and similar to the exposure to sub-inhibitory concentration of FF or TAP alone. The degree of minimum inhibitory concentration (MIC) reduction in FF could reach 75% (1/4 MIC) or more (up to 1/8 MIC for P. multocida, 1/16 for A. pleuropneumoniae) when combined with 1/4 MIC of TAP (or 1/8 for A. pleuropneumoniae). The synergism or FICI ≤ 0.625 of FF with oxytetracycline (47%), doxycycline (69%), and erythromycin (56%) was also evident, and worth further investigation for FF as a central modulator facilitating synergistic effects with these antimicrobials. Taken together, synergistic FF + TAP combination was effective against swine pulmonary isolates of A. pleuropneumoniae and P. multocida both in vitro and in vivo. Thus, this study may offer a potential alternative for the treatment of A. pleuropneumoniae and P. multocida infections and has the potential to greatly reduce drug residues and withdrawal time.

Antibiotic treatment in early life influences gastrointestinal (GI) microbial composition and function. In humans, the resultant intestinal dysbiosis is associated with an increased risk for certain diseases later in life. The objective of this study was to determine the temporal effects of antibiotic treatment on the GI microbiome of young cats. Fecal samples were collected from cats randomly allocated to receive either amoxicillin/clavulanic acid (20 mg/kg q12h) for 20 days (AMC group; 15 cats) or doxycycline (10 mg/kg q24h) for 28 days (DOX group;15 cats) as part of the standard treatment of upper respiratory tract infection. In addition, feces were collected from healthy control cats (CON group;15 cats). All cats were approximately two months of age at enrolment. Samples were collected on days 0 (baseline), 20 or 28 (AMC and DOX, respectively; last day of treatment), 60, 120, and 300. DNA was extracted and sequencing of the 16S rRNA gene and qPCR assays were performed. Fecal microbial composition was different on the last day of treatment for AMC cats, and 1 month after the end of antibiotic treatment for DOX cats, compared to CON cats. Species richness was significantly greater in DOX cats compared to CON cats on the last day of treatment. Abundance of Enterobacteriales was increased, and that of Erysipelotrichi was decreased in cats of the AMC group on the last day of treatment compared to CON cats. The abundance of the phylum Proteobacteria was increased in cats of the DOX group on days 60 and 120 compared to cats of the CON group. Only minor differences in abundances between the treatment groups and the control group were present on day 300. Both antibiotics appear to delay the developmental progression of the microbiome, and this effect is more profound during treatment with amoxicillin/clavulanic acid and one month after treatment with doxycycline. Future studies are required to determine if these changes influence microbiome function and whether they have possible effects on disease susceptibility in cats.

Dysbiosis and perturbations of fecal metabolic profiles have been reported in dogs with inflammatory bowel disease. Currently the incidence of dysbiosis and the fecal metabolomic profile in Yorkshire Terriers with chronic enteropathy (YTE) and the effects of treatment are unknown. This prospective observational study analyzed the dysbiosis index (DI) and fecal bile acid, sterol and fatty acid profiles in 14 Yorkshire Terriers with active YTE, 11 dogs in clinical remission, and 26 healthy Yorkshire Terriers. YTE was associated with dysbiosis and a significant increase in fatty acids (docosanoate, p = 0.002; gondoate, p = 0.026; erucate, p < 0.001; nervonate, p < 0.001; linolenate, p < 0.001), and plant sterols (campesterol, p < 0.001; brassicasterol, p = 0.024). The abundances of Fusobacterium (p < 0.001) and Cl. hiranonis (p = 0.018) and the concentrations of the secondary bile acid ursodeoxycholic acid (p = 0.033) and the plant sterol sitostanol (p = 0.003) were significantly decreased compared to healthy dogs. Dysbiosis, abundances of Fusobacterium, Cl. hiranonis and fecal concentrations of bile acids and sterols did not recover after treatment, while fecal fatty acid concentrations decreased in treated dogs. YTE is associated with dysbiosis and changes in bile acid, fatty acid, and sterol metabolism. These changes only recovered partially despite clinical remission. They might be breed-specific and involved in the pathogenesis of YTE.

Antibiotic treatment in early life influences gastrointestinal (GI) microbial composition and function. In humans, the resultant intestinal dysbiosis is associated with an increased risk for certain diseases later in life. The objective of this study was to determine the temporal effects of antibiotic treatment on the GI microbiome of young cats. Fecal samples were collected from cats randomly allocated to receive either amoxicillin/clavulanic acid (20 mg/kg q12h) for 20 days (AMC group; 15 cats) or doxycycline (10 mg/kg q24h) for 28 days (DOX group;15 cats) as part of the standard treatment of upper respiratory tract infection. In addition, feces were collected from healthy control cats (CON group;15 cats). All cats were approximately two months of age at enrolment. Samples were collected on days 0 (baseline), 20 or 28 (AMC and DOX, respectively; last day of treatment), 60, 120, and 300. DNA was extracted and sequencing of the 16S rRNA gene and qPCR assays were performed. Fecal microbial composition was different on the last day of treatment for AMC cats, and 1 month after the end of antibiotic treatment for DOX cats, compared to CON cats. Species richness was significantly greater in DOX cats compared to CON cats on the last day of treatment. Abundance of Enterobacteriales was increased, and that of Erysipelotrichi was decreased in cats of the AMC group on the last day of treatment compared to CON cats. The abundance of the phylum Proteobacteria was increased in cats of the DOX group on days 60 and 120 compared to cats of the CON group. Only minor differences in abundances between the treatment groups and the control group were present on day 300. Both antibiotics appear to delay the developmental progression of the microbiome, and this effect is more profound during treatment with amoxicillin/clavulanic acid and one month after treatment with doxycycline. Future studies are required to determine if these changes influence microbiome function and whether they have possible effects on disease susceptibility in cats.

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| INTRODUC TI ONDomestic rabbits are direct descendents of European rabbits (Oryctolagus cuniculus) and are characterized by wide phenotypic diversity with more than 200 breeds recognized worldwide. The breeds vary considerably in size, body shape, ear length, coat color, and fur type.These diversities are reflected in a wide range of commercial rabbit uses, including the production of wool, fur, and meat. Moreover, rabbits have many inherited diseases common to humans, making them valuable models for laboratory testing. 1,2 In recent years, numerous breeds Abstract Background: A number of domestic rabbit (Oryctolagus cuniculus) breeds exist, and the pet rabbit population consists of a variety of pure-and crossbred animals.However, the reference intervals (RIs) for rabbits are limited by outdated methods and a single-breed source.Objective: This study aimed to establish more complete, updated erythrocytic and biochemical RIs for the crossbred pet rabbit population to improve routine diagnostic accuracy in clinical practice, and to examine the effects of crossbreeding on erythrocytic and biochemical parameters.Methods: Blood specimens were collected from 85 clinically healthy crossbred pet rabbits representing a wide range of breeds. RIs for the erythrocyte indices and 12 chemistry analytes were determined as recommended by the American Society for Veterinary Clinical Pathology guidelines. The results were compared with four widely used RIs. Age and sex differences for all variables were statistically analyzed. Results:The results diverged from the RIs for New Zealand white rabbits, indicating that not all RIs from this species are appropriate for use in exotic animal practices.Breed-associated variations were evident for aspartate amino transferase, alkaline phosphatase, and glucose, while crossbreed effects were found for total protein, albumin, blood urea nitrogen, creatinine, calcium, and phosphate. Statistically significant differences and clinical relevance among age groups were detected for hemoglobin, hematocrit, and creatinine. Conclusions:Establishing RIs specifically for crossbred pet rabbits is desirable for clinicians treating pet rabbits of various breeds and ages. Age-specific RIs for this population warrants further investigation. K E Y W O R D Sage-related effect, breed-specific variation, crossbreed effect, reference intervals