The Fecal Microbiota of Dogs Switching to a Raw Diet Only Partially Converges to That of Wolves.

The genomic signature of dog domestication reveals adaptation to a starch-rich diet compared with their ancestor wolves. Diet is a key element to shape gut microbial populations in a direct way as well as through coevolution with the host. We investigated the dynamics in the gut microbiota of dogs when shifting from a starch-rich, processed kibble diet to a nature-like raw meat diet, using wolves as a wild reference. Six healthy wolves from a local zoo and six healthy American Staffordshire Terriers were included. Dogs were fed the same commercial kibble diet for at least 3 months before sampling at day 0 (DC), and then switched to a raw meat diet (the same diet as the wolves) for 28 days. Samples from the dogs were collected at day 1 (DR1), week 1 (DR7), 2 (DR14), 3 (DR21), and 4 (DR28). The data showed that the microbial population of dogs switched from kibble diet to raw diet shifts the gut microbiota closer to that of wolves, yet still showing distinct differences. At phylum level, raw meat consumption increased the relative abundance of Fusobacteria and Bacteroidetes at DR1, DR7, DR14, and DR21 (q < 0.05) compared with DC, whereas no differences in these two phyla were observed between DC and DR28. At genus level, Faecalibacterium, Catenibacterium, Allisonella, and Megamonas were significantly lower in dogs consuming the raw diet from the first week onward and in wolves compared with dogs on the kibble diet. Linear discriminant analysis effect size (LEfSe) showed a higher abundance of Stenotrophomonas, Faecalibacterium, Megamonas, and Lactobacillus in dogs fed kibble diet compared with dogs fed raw diet for 28 days and wolves. In addition, wolves had greater unidentified Lachnospiraceae compared with dogs irrespective of the diets. These results suggested that carbohydrate-fermenting bacteria give way to protein fermenters when the diet is shifted from kibble to raw diet. In conclusion, some microbial phyla, families, and genera in dogs showed only temporary change upon dietary shift, whereas some microbial groups moved toward the microbial profile of wolves. These findings open the discussion on the extent of coevolution of the core microbiota of dogs throughout domestication.

One-step triplex reverse-transcription PCR detection of porcine epidemic diarrhea virus, porcine sapelovirus, and porcine sapovirus.

Swine diarrhea can be caused by multiple agents, including porcine epidemic diarrhea virus (PEDV), porcine sapelovirus (PSV), and porcine sapovirus (SaV). We designed a one-step triplex reverse-transcription PCR (RT-PCR) detection method including 3 pairs of primers that focused on the S1 gene of PEDV, a conserved gene of PSV, and the VP1 gene of SaV. The optimal concentrations of upstream and downstream primers in the triplex RT-PCR were 0.24 µM for PEDV, 0.15 µM for PSV, and 0.2 µM for SaV, and the optimal annealing temperature was 55.5°C. Triplex RT-PCR assessment of 402 piglet diarrhea samples was compared with conventional individual RT-PCR. Concordance rates in both tests for individual viruses were 100%, 97.6%, and 94.4% for PEDV, PSV, and SaV, respectively. PEDV, PSV, and SaV were detected in 57.2%, 10.4%, and 9.0% of the samples, respectively. The high sensitivity and specificity of this triplex RT-PCR-based detection method for PEDV, PSV, and SaV could allow rapid detection and analysis of mixed infections by these 3 viruses.

Molecular characterization and phylogenetic analysis of porcine epidemic diarrhea virus isolates in Eastern China.

INTRODUCTION: Porcine epidemic diarrhea virus (PEDV) is one of the most common viral pathogens causing swine diarrhea. METHODOLOGY: We performed a genetic evolution analysis of the S1 gene of endemic PEDV strains in Eastern China. The S1 genes of 37 PEDV-positive samples were amplified and sequenced, and compared to the standard CV777 strain, 120 nucleotides were found to have mutations. RESULTS: The nucleotide and deduced amino acid homologies between the sequences and those of the CV777 strain were 90%-91% and 88.2%-90%, respectively, and their homologies to the vaccine strain were 88.6%-89.7% and 86.2%-87.8%, respectively. Genetic evolution and variation analyses indicated that the 37 PEDV strains belonged to genogroup 2-1, while the CV777 strain, vaccine strain, and earlier Chinese strains all belonged to genogroup 1-1. CONCLUSIONS: The newly emerged clinical PEDV strains indicate that the PEDV CV777 vaccine currently used in China may not fully protect pigs from infection with recent epidemic strains, and will require the development of new vaccine strains.