Evaluation of a yeast β-glucan blend in a pet food application to determine its impact on stool quality, apparent nutrient digestibility, and intestinal health when fed to dogs

Abstract

Oral supplementation of β-glucans may be able to improve the health of companion animals. However, little is understood regarding the effects of yeast β-glucan on diet processing and intestinal function. Therefore, the objectives of this research were to determine the carry through of yeast β-glucan during extruded diet production and its impact on diet utilization by dogs. Three diets were formulated to contain increasing levels of a yeast β-glucan blend at 0, 0.012 and 0.023% inclusion. Processing inputs were held constant during extrusion to allow for evaluation of output parameters and physical characteristics of kibble. Yeast β-glucan concentration was analyzed in extruded diets using the glucan enzymatic method, resulting in >100% recovery. Twenty-four Labrador Retrievers were assigned to one of three dietary groups of 8 dogs each with an equal distribution of sex and age. Dogs were fed dietary treatments for 24-d adaption followed by 4-d total fecal collection. Feces were scored on a 1-5 scale, with 1 representing liquid diarrhea and 5 hard pellet-like with a fecal score of 3.5-4 considered ideal. Fresh fecal samples were collected for analysis of short chain fatty acid concentrations. Apparent total tract digestibility was calculated by total fecal collection (TFC) and titanium (TI) marker methods. Data were analyzed using a mixed model procedure in software (version 9.4, SAS Institute, Inc., Cary, NC). Dry bulk density, kibble diameter, and kibble length did not differ among dietary treatments. Intake was similar among dietary treatments (P > 0.05). Dogs required about 26% more food than estimated [130*BWkg0.75] to maintain body weight among all treatments. Fecal score was not different (P > 0.05) among dietary treatments but was lower than ideal at an average of 2.6. Nutrient digestibility was not affected (P > 0.05) by inclusion of the yeast β-glucan. By method, the TFC procedure resulted in higher (P< 0.05) digestibility values when compared to the TI procedure. In addition, yeast β-glucan did not alter short or branched chain fatty acid proportions. Overall, processing parameters, physical characteristics of kibble, stool quality, nutrient digestibility, and intestinal health in dogs were not affected by the yeast β-glucan blend.

Potential benefits of yeast Saccharomyces and their derivatives in dogs and cats: a review

“…Bastos et al ( 5) also observed lower fecal ammonia levels after an abrupt dietary change in dogs supplemented with live yeast compared to control ones. However, these finding have not been consistent as other authors have reported higher fecal pH (82,90,95) or no change (24,74,81,86).…”

“…As a result of this, bacterial fermentation in the large intestine would be reduced as less fermentable substrate would be available. However, one should be cautious with this hypothesis as in vivo studies with yeast β-glucans have reported increases in apparent total tract digestibility (ATTD) in pre-ruminant calves (23) or no changes at all in dogs (24). Other possible mechanism of yeast to modulate nutrient digestibility is the production of enzymes, such as amylases, lipases, and proteases.…”

“…Short chain fatty acids are rapidly absorbed by colonocytes, thus determining their levels in vivo can be challenging, perhaps contributing to the varying results reported. Unaltered fecal concentrations of SCFA have been reported when yeast or yeast by-products were used (24,74,81,95,97). However, decreases in isovalerate and/or increases in propionate, butyrate, acetate and total SCFA when using yeast products have been reported by different authors (5,75,81,95).…”

“…However, the potential effect of yeast on weight is not clear. Several studies reported no effect on feed intake or body weight (BW) in dogs (24,73,81,86,90,97,105). However, Stercova et al (74) observed that dogs fed capsulated live yeast SC showed a higher increase of BW compared with the control ones, but the difference was very limited.…”

Potential Effects of Prebiotics on Gastrointestinal and Immunological Modulation in the Feeding of Healthy Dogs: A Review

“…In addition, it is important to filter that the beneficial bacteria responsible for metabolizing the oligosaccharides are strains of Lactobacilli and Bifidobacteria. The most known prebiotics and used by the petfood industry are lactulose, fructooligosaccharides (FOS), inulin, yeast cell wall, and mannanoligosaccharides (MOS) [6]; moreover, there has been a recent increase in the number of studies that have investigated the potential effects of beta-glucans [7]. However, in addition, there is a range of potential prebiotics that are being studied.…”