Large dogs are prone to producing feces of poorer quality than small dogs, partly due to a higher colonic permeability. Fermentation of undigested proteins would have deleterious effects on the colonic mucosa. The aim of the study was to assess the effect of dietary protein source and level on fecal quality and tight junction (TJ) proteins in the colon of small and large dogs. Five Miniature poodles (MP) and 6 German shepherds (GS) spayed dogs were fed 2 diets varying in main protein sources (wheat gluten: WG, and poultry meal: PM) and levels (LP: 21.4%, and HP: 34.8% CP as fed) in a 2x2 wk cross-over study design. Feces were scored daily (1=dry and hard to 5=liquid). Proximal and distal colonic biopsies were taken at the end of each 14-d period. mRNA expression of claudins 4 and 7 (CLN4 and CLN7), junctional adhesion molecule (JAM), occludin (OCLD) and zonula occludens 1 and 2 (ZO-1 and ZO-2) were measured by real time-PCR. Fecal score data was analyzed using Kruskal-Wallis test and gene expression using repeated-measures ANOVA. Fecal score was higher in GS dogs (p<0.001 for diet WG-LP, p=0.006 for PM-HP), and when feeding PM-HP (p=0.010 for MP, p=0.003 for GS). Protein digestibility was WG: 87.9% and PM: 83.4% (p<0.001). The expression of CLN4 and ZO-2 in the proximal colon was higher (p=0.008 and p=0.088) in GS than MP dogs. Higher expression of CLN7 was observed (p=0.059 in the proximal and p=0.069 in the distal colon) of GS than MP. The expression of OCLD was higher in GS than MP, in the proximal and distal colon (p=0.002 and p=0.058, respectively) and when feeding WG-LP and PM-HP (p=0.046 and p=0.013, respectively). No effects of diet, breed or biopsy location were found for JAM and ZO-1. Feeding highly digestible protein source WG at low level leads to an improvement of fecal score and moisture but it does not influence colonic TJ expression. Poorer fecal score in GS compared with MP would not be related to lower TJ expression in the colon of GS dogs.
Influence of dietary protein on fecal quality and colonic tight junction gene expression in Miniature poodles and German shepherds
VENDA DA GRACA NERY, JOANA MARIA;
2009-01-01
Abstract
Large dogs are prone to producing feces of poorer quality than small dogs, partly due to a higher colonic permeability. Fermentation of undigested proteins would have deleterious effects on the colonic mucosa. The aim of the study was to assess the effect of dietary protein source and level on fecal quality and tight junction (TJ) proteins in the colon of small and large dogs. Five Miniature poodles (MP) and 6 German shepherds (GS) spayed dogs were fed 2 diets varying in main protein sources (wheat gluten: WG, and poultry meal: PM) and levels (LP: 21.4%, and HP: 34.8% CP as fed) in a 2x2 wk cross-over study design. Feces were scored daily (1=dry and hard to 5=liquid). Proximal and distal colonic biopsies were taken at the end of each 14-d period. mRNA expression of claudins 4 and 7 (CLN4 and CLN7), junctional adhesion molecule (JAM), occludin (OCLD) and zonula occludens 1 and 2 (ZO-1 and ZO-2) were measured by real time-PCR. Fecal score data was analyzed using Kruskal-Wallis test and gene expression using repeated-measures ANOVA. Fecal score was higher in GS dogs (p<0.001 for diet WG-LP, p=0.006 for PM-HP), and when feeding PM-HP (p=0.010 for MP, p=0.003 for GS). Protein digestibility was WG: 87.9% and PM: 83.4% (p<0.001). The expression of CLN4 and ZO-2 in the proximal colon was higher (p=0.008 and p=0.088) in GS than MP dogs. Higher expression of CLN7 was observed (p=0.059 in the proximal and p=0.069 in the distal colon) of GS than MP. The expression of OCLD was higher in GS than MP, in the proximal and distal colon (p=0.002 and p=0.058, respectively) and when feeding WG-LP and PM-HP (p=0.046 and p=0.013, respectively). No effects of diet, breed or biopsy location were found for JAM and ZO-1. Feeding highly digestible protein source WG at low level leads to an improvement of fecal score and moisture but it does not influence colonic TJ expression. Poorer fecal score in GS compared with MP would not be related to lower TJ expression in the colon of GS dogs.
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