Influence of dietary protein content and source on colonic fermentative activity in dogs differing in body size and digestive tolerance1

Abstract

Low-consistency, high-moisture feces have been observed in large dogs (Canis lupus familiaris), compared with small dogs, and particularly in sensitive breeds (e.g., German Shepherd dogs). The aim of this work was to determine if greater colonic protein fermentation is responsible for poorer fecal quality in large sensitive dogs. Twenty-seven bitches were allotted to 4 groups based on size and digestive sensitivity: small, medium, large tolerant, and large sensitive. Five experimental diets varying in protein source [highly digestible wheat gluten (WG) vs. medium digestible poultry meal (PM), and protein concentration from 21.4 to 21.6 (LP) to 38.2 to 39.2% CP (HP)] were tested. Diets were fed for 14 d and followed by a 12-d transition period. Digestive fermentation by-products were investigated in fresh stools [ammonia, phenol, indole, and short chain fatty acids including acetate, propionate, and butyrate (C2 to C4 SCFA), branched-chain fatty acids (BCFA), and valerate] and in urine (phenol and indole). Bacterial populations in feces were identified. The PM diets resulted in greater fecal concentrations of ammonia, BCFA, valerate, indole, and C2 to C4 SCFA than WG diets (P = 0.002, P < 0.001, P = 0.039, P = 0.003, and P = 0.012, respectively). Greater concentrations of ammonia, BCFA, and valerate were found in the feces of dogs fed HP compared with LP diets (P < 0.001, P < 0.001, and P = 0.012, respectively). The concentrations of ammonia, valerate, phenol, and indole in feces of large sensitive dogs were greater (P < 0.001, P < 0.001, P = 0.002, and P = 0.019, respectively) compared with the other groups. The Enterococcus populations were greater in feces of dogs fed with PMHP rather than WGLP diets (P = 0.006). Urinary phenol and indole excretion was greater when dogs were fed PM than WG diets (P < 0.001 and P = 0.038, respectively) and HP than LP diets (P = 0.001 and P = 0.087, respectively). Large sensitive dogs were prone to excrete a greater quantity of phenol in urine (P < 0.001). A diet formulated with highly digestible protein, such as WG, led to reduced concentrations of protein-based fermentation products in feces together with improved fecal quality in dogs, especially in large sensitive ones. Poor fecal quality in large sensitive dogs could be partly related to the pattern of protein fermentation in the hindgut.

Efficacy and Tolerance of Two Low-Carbohydrate Diets in Large Adult Dogs with Digestive Sensitivity: A Randomized, Cross-Over, Blinded Evaluation

“…Several specificities in the composition of SENSI versus ADULT could explain its better results obtained in the present study. As observed by Nery et al [17], the higher the protein content (from 22 to 39% DM), the greater was the faecal score and the higher was the faecal fermentation [15,17]. In our study, the reduction of the protein content in SENSI vs ADULT (32 vs 39% DM) may have resulted in the normalization of faecal moisture and consistency as well as the reduction of fetid odours.…”

“…However, large dogs, and more specifically certain sensitive breeds such as German Shepherd, Labrador Retrievers, Great Danes or Giant Schnauzers, are known to have particularly sensitive digestive systems that are manifested by exacerbated colonic fermentations and lower faecal consistency [13][14][15][16][17][18], and whatever the breed, some individual dogs may also have digestive sensitivity without there being a specific cause. While a diet formulated with highly digestible proteins improves faecal quality in dogs, especially in large sensitive ones [15,17,18], increased dietary protein concentrations are suspected to lead to a greater faecal score by affecting the quantity of substrate available for colonic fermentation [15,18].…”

A diet change from dry food to beef induces reversible changes on the faecal microbiota in healthy, adult client-owned dogs

“…The influence of diarrhoea is therefore not directly reflected in our data, and might explain why Clostridium perfringens was not significantly increased by the HMB diet. Anyhow, the increased amount of isovaleric acid and pH in faecal samples of dogs fed HMB compared to CD1 and CD2, indicates that undigested proteins may reach the colon in at least some dogs consuming higher levels of proteins [20], and the proteolytic activities of bacteria may lead to increased levels of potentially detrimental metabolites. The implications for dog health are currently not known.…”

Impact of diets with a high content of greaves-meal protein or carbohydrates on faecal characteristics, volatile fatty acids and faecal calprotectin concentrations in healthy dogs

“…In vitro and in vivo studies have shown that the final products of bacterial fermentation mostly depend on the chemical composition of the chyme that reaches the large intestine [2,3]. For instance, if there is a lack of carbohydrates (e.g., wheat, maize) in the diet, the microorganisms ferment amino acids into short-chain fatty acids (SCFAs) and ammonia to obtain energy [4]. A sufficient throughput of carbohydrate leads to a decrease in luminal nitrogenous compounds and an increase in faecal bacterial mass [5].…”