GI05 - The Impact of Fecal Identification Markers on the Feline Microbiome

Abstract: Background: Fecal collection in cats is required for research and clinical purposes but fecal identification is limited by feline elimination behaviors in group-housing and multi-cat households. Crayon shavings and glitter have been used as fecal markers, but their impact on the fecal microbiome is unknown.

Objective: To determine the impact of fecal identification markers, specifically crayon and glitter, on the feline microbiome.

Animals: This clinical trial was performed in six healthy and sterilized purpose-bred cats (3 male, 3 female) group-housed in a dedicated research facility.

Methods: A randomized crossover experiment was performed. Cats received either glitter or crayon shavings mixed in a feline adult maintenance diet for 14 days. A 14-day washout was performed between crossovers. Feces was collected daily from each cat for 16S rRNA gene sequencing (V4 region). Amplicon analysis was performed in R-studio (dada2; phyloseq). Pairwise PERMANOVA analysis compared samples across experimental phases and marker order.

Results: Fecal identification markers were readily identified in the feces of all cats. Statistically significant changes to the microbiome were identified with marker order (P < 0.05) and across experimental phases (P < 0.05) for 5/6 cats. Microbiome changes were cat-dependent (P < 0.001), suggesting idiosyncratic microbiome responses to glitter and crayon.

Conclusions and Clinical Importance: Both glitter and crayon allow for identification of individual feline fecal samples; however, these markers may impact the microbiome and therefore are not recommended in studies with microbiome endpoints. The difference in response to these markers among cats highlights the individuality of the feline microbiome.