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.

Effects of a 28-day feeding trial of grain-containing versus pulse-based diets on cardiac function, taurine levels and digestibility in domestic dogs

“…Total bilirubin and indirect bilirubin were also seen to decrease in the pulse-inclusive diets, the cause for this however remains unknown. The current study in Beagles observed increases in serum phosphorus after feeding the lentil-based diet which agrees with a previous 28-day study in adult Labrador retrievers fed a diet high in both peas and lentils as well as 7-and 28-day studies in Beagles fed a commercial pulse-containing diet [ 15 , 41 , 42 ]. However, in the current study RBC counts were similar after feeding all three lab-made diets.…”

“…Only a few previous feeding studies examining pulse-inclusive diets have been conducted in healthy dogs or in breeds not known to be susceptible to DCM. Of these, several reported no effect on echocardiography or blood indicators of DCM after feeding laboratory Beagles pea- or fava bean-based diets for only 7 days [ 21 , 41 ] or faba bean based diets for 28-days [ 41 , 42 ]. Also, a clinical trial where a similarly high pea-based diet (60% as fed) was fed for 12-weeks to client-owned dogs of variable breeds reported increased LV diastolic dimensions without a change in stroke volume or cardiac output [ 16 ].…”

Collaborative Metabolism: Gut Microbes Play a Key Role in Canine and Feline Bile Acid Metabolism

“…Over the past 5 years, microbial-derived BAs have been increasingly studied in canines ( Table 1 ). Studies in healthy dogs have characterized the microbial-derived BAs during the development of puppies [ 114 ], as well as the impact of antimicrobials [ 59 , 115 , 116 , 117 , 118 ] and diet [ 119 , 120 , 121 , 122 , 123 , 124 , 125 , 126 ] on the BA pools of healthy dogs. Additional studies on disease states have largely focused on the context of gastrointestinal [ 52 , 64 , 127 , 128 , 129 , 130 , 131 ] and pancreatic disease [ 128 , 132 ], with additional information characterizing microbial-derived BAs in canine obesity [ 119 , 125 ], diabetes mellitus [ 113 ], and myxomatous mitral valve disease (MMVD) [ 133 ].…”

“…Therefore, in healthy dogs, additional multi-omics studies are required to characterize collaborative BA metabolism, specifically describing canine gut microbes mechanistically responsible for BA biotransformations in health. In the following sections, the impact of antimicrobials [ 59 , 115 , 116 , 117 , 118 ] and diet [ 119 , 120 , 121 , 122 , 123 , 124 , 125 , 126 ] on the BA pools of healthy dogs will be reviewed.…”

“…As expected, diet impacts the gut microbiota and microbial-derived SBAs, but the response is dependent on the diet fed. Diet types studied to date in dogs include the following: high protein, high fat, low fiber (HP-HF-LF) [ 126 ]; high protein, high fat, low fiber consistent with bones and raw food (BARF) [ 121 ]; high protein, high fiber (HP-HF) [ 122 ]; and grain-free diets [ 120 , 123 , 124 ].…”