Developmental intestinal microbiome alterations in canine fading puppy syndrome: a prospective observational study. OK120

Background: Fading puppy syndrome (FPS) is a fatal condition in neonatal dogs. Intestinal microbial alterations, although never investigated, are possibly involved in its pathophysiology. Objectives: The study examined the occurrence of FPS and its associations with dam, puppy and husbandry characteristics, compared the intestinal microbial diversity of healthy puppies and those with FPS, and examined whether intestinal microbiomes are predictive of FPS. Methods: Day 1 and 8 post-partum (PP) fecal samples were collected from healthy puppies and puppies which later had FPS. Microbial compositional structure, including alpha and beta diversities and relative abundance of specific taxa were compared between groups. Microbial data was applied to a machine-learning model to assess the predictive performance of microbial indices of FPS or death. Results: FPS occurred in 22/165 puppies (13%), with 100% mortality rate. FPS was associated (P <0.001) with decreased Day-1 PP puppy activity. Days 1 (P = 0.003) and 8 (P = 0.005) PP fecal beta-diversities were different in puppies with FPS vs healthy ones. Increased Proteobacteria / Firmicutes ratio, increased relative abundance of Pasteurellaceae and decreased relative abundance of Clostridia were associated with FPS. A machine learning model showed that Day-1 PP fecal microbiome composition accurately predicted FPS-related death. Conclusions: Specific intestinal microbial phenotypes are associated with FPS. Day-1 PP intestinal microbiome composition is predictive of FPS-related death, reflecting significant role of microbiome alterations in FPS. These may serve as useful microbial indices for early diagnosing puppies at risk of FPS and providing novel specific therapeutic targets.