Influence of dietary protein on fecal quality and gene expression of apoptosis‐ and immune‐related genes in the colon of Miniature Poodles and German Shepherds

Abstract

Digestive tolerance vary among dog breeds, which could be partially attributed to higher colonic fermentation. Highly digestible protein sources, such as wheat gluten, could lead to lower colonic protein fermentation. Our aim was to assess the effect of dietary protein on fecal quality, and mRNA expression of genes involved in colonocyte apoptosis and mucosa immune responses.Five Miniature Poodles (MP) and 6 German Shepherds (GS) were fed with diets varying in protein source and level: low‐protein wheat gluten meal (LP) and high‐protein poultry meal (HP). Feces were scored daily (1=dry; 5=liquid) and fecal moisture was analyzed. Colonic biopsies followed each 14‐d trial period. The mRNA expression of proteins involved in apoptosis (Bcl‐2, Casp3), and in mucosa immune responses (IL7, TLR2, TLR4) was analyzed by RT‐real time PCR.Fecal score and moisture were higher in GS than MP, and when feeding HP diet. The expression of IL7 was higher in GS than MP (P < 0.05), and when dogs were fed with HP diet (P = 0.03). The TLR2 mRNA expression was higher in the proximal colon of GS than MP (P = 0.08), and when feeding HP diet to GS (P = 0.03).Up‐regulation of immune‐related proteins could indicate a higher response to commensal bacteria, leading to a lower quality of feces. Diets containing low levels of highly digestible proteins could be an adequate nutritional strategy to improve fecal quality. Research supported by Royal Canin.