The Effects of Fermentation of Low or High Tannin Fava Bean-Based Diets on Glucose Response, Cardiovascular Function, and Fecal Bile Acid Excretion during a 28-Day Feeding Period in Dogs: Comparison with Commercial Diets with Normal vs. High Protein

Abstract

We have shown that feeding dogs fava bean (FB)-based diets for 7 days is safe and FB flour fermentation with Candida utilis has the potential to decrease FB anti-nutritional factors. In the present study, the effects of 28-day feeding of 4 different FB-based test dog foods containing moderate protein (~27% dry matter (DM)) were compared with two commercial diets with normal protein (NP, grain-containing, ~31% DM protein) or high protein (HP, grain-free, ~41% DM protein). Health parameters were investigated in beagles fed the NP or HP diets or using a randomized, crossover, 2 × 2 Latin square design of the FB diets: unfermented high-tannin (UF-HT), fermented high-tannin (FM-HT), unfermented low-tannin (UF-LT), and fermented low-tannin (FM-LT). The results showed that fermentation increased glucose tolerance, increased red blood cell numbers and increased systolic blood pressure, but decreased flow-mediated vasodilation. Taken together, the overall effect of fermentation appears to be beneficial and improved FB nutritional value. Most interesting, even though the HP diet was grain-free, the diet did contain added taurine, and no adverse effects on cardiac function were observed, while glucose tolerance was impaired compared to NP-fed dogs. In summary, this study did not find evidence of adverse cardiac effects of pulses in ‘grain-free’ diets, at least not in the relatively resistant beagle breed over a 28-day period. More importantly, fermentation with C. utilis shows promise to enhance health benefits of pulses such as FB in dog food.