POSTER ABSTRACTS
sequencing followed by imputation. We combined the genetic data with phenotypes from the Health and Life Experience Survey and performed a genome-wide association study (GWAS) using a mixed linear model of the GCTA tool with age and sex included as covariates. Lead SNPs were identified by linkage-disequilibrium (LD) based clumping. We conducted a meta-analysis for body size using METAL to combine the DAP weight GWAS (n=2314) with the Darwin’s Ark height GWAS (n=1844). Our meta-analysis result captures genome-wide significant SNPs appearing in genes previously reported to be associated with body size, including in IGF1, LCORL, HMGA2, and SMAD2. We tested for SNPs specifically associated with weight and not height in the DAP weight GWAS by controlling for height-associated SNPs identified in the Darwin’s Ark GWAS. The major associations affecting body size disappear while several significant SNPs appear in KIAA1239, SPEG, and various intergenic regions, representing potential new associations specific to weight, although further analysis is needed. Combining these results with the detailed health information collected by the Dog Aging Project will enable exploration of how body size influences disease risk in dogs.
#62 Evaluating feline rectum fecal sample collection method using mineral oil lubrication for microbiome studies
Xiaolei Ma1,2 , Emily Brinker1,3, Wenqi Cao1, Emily C. Graff1,3, Xu Wang1,3,4,5 xzm0021@auburn.edu
1Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL, USA, 2School of Life Sciences and Technology, Tongji University, Shanghai, China, 3Scott-Ritchey Research Center, College of Veterinary Medicine, Auburn University, Auburn, AL, USA, 4Center for Advanced Science, Innovation and Commerce, Alabama Agricultural Experiment Station, Auburn, AL, USA, 5HudsonAlpha Institute for Biotechnology, Huntsville, AL, USA Fecal specimens are critical for diagnosis and microbiome research. For domestic cats, the dry collection approach using a fecal loop into the rectum and descending colon often results in little to no fecal specimens, which leads to insufficient amounts of material for some samples and thus an imbalanced experimental design. The fecal loop method can cause abrasion to the intestinal wall, leading to the shedding of host cells and/or bleeding, which increases host DNA contamina- tion. Because low-stress handling and fear reduction techniques are the new standard of care for veterinary patients, chemical restraint has been adopted by veterinarians. Using a lubricant can additionally minimize stress, discomfort, and pain in the patient. However, the effect of lubrication on feline microbiome analysis has not been studied. To address this, we enrolled eight 6-year-old male, neutered, domestic short-haired cats housed in a research facility. The gut microbiomes were investigated for fecal sample collection with and without lubrication using whole-genome shotgun metagenomic sequencing. There were no significant differences between the two groups in the microbial DNA yield in ng/mg fecal sample (P = .95), metagenomic sequencing yield in GB sequences (P = .20), the proportion of host contamination (P = .84), relative taxonomy abundance (P > .80), or the number of microbial genes covered (P = .31). In conclusion, fecal sampling with mineral oil lubrication did not change the microbial DNA extraction yield, metagenomic sequencing yield, level of host contamination, the microbial composition and diversity in subsequent gut micro- biome analyses. Here we reported a proven feline-friendly protocol for fecal sample collection in clinical and research settings for gut microbiome analyses.
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