Interpretive Summary: Graded dietary resistant starch concentrations on apparent total tract macronutrient digestibility and fecal fermentative end products and microbial populations of healthy adult dogs
By Anne Zinn
A study recently published in the Journal of Animal Science evaluated the effects of 0%, 1%, 2%, 3%, and 4% dietary resistant starch (Hi-maize 260) on apparent total tract macronutrient digestibility, fecal characteristics, fermentative end-product concentrations, and microbiota of healthy adult dogs. Resistant starch is fermentable by gut microbiota and effectively modulates fecal short-chain fatty acid concentrations in pigs, mice, and humans and may have similar beneficial effects on the canine gut but has not been well studied. Beloshapka et al. hypothesized that increased resistant starch consumption would increase fecal short-chain fatty acids concentrations and reduce protein fermentation products and that increased resistant starch would beneficially alter fecal microbiota populations, including increases in Ruminococcus, Parabacteroides, and Faecalibacterium, taxa that have been shown to degrade RS or be altered by RS consumption in humans previously.
Results of the present study demonstrated that apparent total tract dry matter, organic matter, crude protein, fat and gross energy digestibilities and fecal pH were decreased with increased resistant starch consumption; fecal output increased with increased resistant starch consumption, but fecal scores and fecal fermentative end-product concentrations were not affected by resistant starch consumption. The results may indicate that canine GI transit time, anatomy, or microbiota populations do not support the use of pure sources of resistant starch as a fermentable dietary fiber source in dogs. Even still, the reduced nutrient and energy digestibility with increasing dietary resistant starch suggest that it may be used to reduce caloric density and have application in obesity diets.
The full study can be found on the Journal of Animal Science webpage.