The Effects of 7 Days of Feeding Pulse-Based Diets on Digestibility, Glycemic Response and Taurine Levels in Domestic Dogs

Abstract

Grain-based carbohydrate sources such as rice comprise 30–50% of commercial pet foods. Some pet foods however have removed the use of grains and have instead incorporated pulses, such as peas and lentils, resulting in grain-free diets. The hypothesis was dog diets with higher levels of dietary fiber will produce a low glycemic response due to decreased rates of digestion and lowered bioavailability of all macronutrients and increased fecal bile salt excretion. This in turn was hypothesized to produce lower plasma concentrations of cysteine, methionine and taurine after 7 days of feeding each test diet in dogs. Six diets were formulated at an inclusion level of 20% available carbohydrate, using white rice flour (grain) or whole pulse flours from smooth pea, fava bean, red lentil or 2 different wrinkled pea varieties (CDC 4,140–4 or Amigold) and fed to beagles in a randomized, cross-over, blinded design. After 7 days feeding each diet, fasting blood glucose was the lowest in the lentil (3.5 ± 0.1 mmol/L) and wrinkled pea (4,140–4; 3.6 ± 0.1 mmol/L) diet periods, while peak glucose levels was lowest after feeding the lentil diet (4.4 ± 0.1 mmol/L) compared to the rice diet. Total tract apparent digestibility of all macronutrients as well as taurine differed among diets yet plasma taurine was not outside normal range. Decreased macronutrient and amino acid digestibility was associated with increasing amylose and dietary fiber content but the specific causative agent could not be determined from this study. Surprisingly, digestibility decreases were not due to increased bile salt loss in the feces since increasing dietary fiber content led to decreased fecal bile salt levels. In conclusion, although pulse-based canine diets have beneficial low glycemic properties, after only 7 days, these pulse-based diets decrease macronutrient and amino acid digestibility. This is likely related at least in part to the lower animal protein content, but on a long-term basis could put domestic dogs at risk for low taurine and dilated cardiomyopathy.

Exploring the Biotechnological Value of Marine Invertebrates: A Closer Look at the Biochemical and Antioxidant Properties of Sabella spallanzanii and Microcosmus squamiger

“…For example, taurine is not an essential amino acid in dogs, since taurine precursors (cysteine and methionine) are used by the liver and the central nervous system to synthesize taurine. However, taurine supplementation can revert dilated cardiomyopathy, a common dog disease, since it is linked to reduced plasma taurine levels [ 88 , 89 , 90 , 91 ]. Overall, our results suggest M. squamiger as a source of taurine for human and veterinary uses, and of fishmeal taurine-rich ingredients.…”

Effects of pulse crop types and extrusion parameters on the physicochemical properties, in vitro and in vivo starch digestibility of pet foods

“…After being chewed to a limited level, in vivo digestion rates of pet food pellets having good integrity may not be as fast as the in vitro enzymatic hydrolysis rates of finely milled samples analyzed in the present study. Therefore, the in vitro starch digestibility data acquired from this research did not consistently reflect the glycemic responses of beagle dogs to these extrudates as illustrated in our most recent work (Quilliam et al, 2021). Additional research is needed to explain the discrepancies between the in vitro starch hydrolysis rates of the ground extrudates and the glycemic responses to the extrudates in a pellet shape.…”

“…In vivo starch digestibility of the extruded pet diets from Section 2.4 was evaluated in beagle dogs according to the method used by Quilliam et al. (2021). Only the samples processed using the C1 condition were selected for the in vivo trials because this condition better resembled those applied for commercial dry pet food production (Adolphe et al., 2015).…”

Roles of plant‐based ingredients and phytonutrients in canine nutrition and health

“…Nonetheless, amino acid digestibility must also be considered. Pulse‐based diets containing higher plant protein and lower animal protein were shown to have lower amino acid digestibility in a recent study (Quilliam et al, 2021). Plasma sulphur‐containing amino acid concentrations (methionine, cysteine and taurine), however, were not compromised after dogs were on pulse‐based diets for 7 days. ● Fatty acids .…”

“…The authors discussed that this effect may have originated from the carbohydrate and fibre content of the soy, and not the protein, particularly via the impact on slowing the rate of nutrient absorption in the intestine. Indeed, glycaemic response has been shown to vary when different grains and pulses were used as a carbohydrate source in extruded diets (Adolphe et al, 2015;Carciofi et al,l., 2008;Quilliam et al, 2021;Rankovic et al,l., 2020;Teixeira et al,l., 2018).…”