Quilliam Chloe, Ren Yikai, Morris Tressa, Ai Yongfeng, Weber Lynn P
Department of Veterinary Biomedical Sciences, Saskatoon, SK, Canada.
Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK, Canada.
Front Vet Sci. 2021 May 5;8:654223. doi: 10.3389/fvets.2021.654223. eCollection 2021.
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.
以谷物为基础的碳水化合物来源，如大米，占商业宠物食品的30%-50%。然而，一些宠物食品已不再使用谷物，而是加入了豆类，如豌豆和小扁豆，从而产生了无谷物饮食。该假设是，膳食纤维含量较高的犬粮由于消化率降低、所有宏量营养素的生物利用度降低以及粪便胆汁盐排泄增加，将产生较低的血糖反应。进而推测，在给犬喂食每种试验日粮7天后，血浆中半胱氨酸、蛋氨酸和牛磺酸的浓度会降低。配制了六种日粮，有效碳水化合物的添加水平为20%，分别使用白米粉（谷物）或来自光滑豌豆、蚕豆、红扁豆或2个不同皱皮豌豆品种（CDC 4,140-4或Amigold）的全豆粉，并以随机、交叉、盲法设计喂食比格犬。在喂食每种日粮7天后，小扁豆日粮期（3.5±0.1 mmol/L）和皱皮豌豆（4,140-4；3.6±0.1 mmol/L）日粮期的空腹血糖最低，而与大米日粮相比，喂食小扁豆日粮后的血糖峰值水平最低（4.4±0.1 mmol/L）。所有宏量营养素以及牛磺酸的全肠道表观消化率在不同日粮之间存在差异，但血浆牛磺酸未超出正常范围。宏量营养素和氨基酸消化率的降低与直链淀粉和膳食纤维含量的增加有关，但本研究无法确定具体的致病因素。令人惊讶的是，消化率降低并非由于粪便中胆汁盐损失增加，因为膳食纤维含量增加导致粪便胆汁盐水平降低。总之，尽管以豆类为基础的犬粮具有有益的低血糖特性，但仅7天后，这些以豆类为基础的日粮就会降低宏量营养素和氨基酸的消化率。这可能至少部分与动物蛋白含量较低有关，但从长期来看，可能会使家犬面临牛磺酸缺乏和扩张型心肌病的风险。
