Extruded cat foods differ greatly in macronutrient distribution compared with wild-type diets (i.e. small mammals, reptiles, birds and insects). Based on the literature, this variability likely impacts faecal microbial populations. A completely randomised design was utilised to test the impacts of two dietary treatments on faecal microbial populations: (1) chicken-based extruded diet (EXT; n 3 cats) and (2) raw 1-3-d-old chicks (CHI; n 5 cats). Cats were adapted to diets for 10 d. Bacterial DNA was isolated from faecal samples and amplicons of the 16S rRNA V4-V6 region were generated and analysed by 454 pyrosequencing. Faeces of cats fed CHI had greater (P < 0·05) proportions of the following bacterial genera: unidentified Lachnospiraceae (15 v. 5 %), Peptococcus (9 v. 3 %) and Pseudobutyrivibrio (4 v. 1 %). Faeces of cats fed EXT had greater (P < 0·05) proportions of Faecalibacterium (1·0 v. 0·2 %) and Succinivibrio (1·2 v. < 0·1 %). Five genera, including Lactobacillus and Bifidobacterium, were present in a majority of samples (two to three out of three) from cats fed EXT, but were not detected in the samples (zero of five) for cats fed CHI. These shifts in faecal bacterial populations compared with feeding a whole-prey diet may impact the functional capacities of the microbiota and its interaction with the host. Further research is warranted to determine the impacts of these shifts on long-term health of domestic cats.
Keywords: CHI, 1–3-d-old chicks; CP, crude protein; EXT, chicken-based extruded diet; Feline nutrition; Gut microbiota; Raw diet.