Comparison of digestibility parameters of commercial dry dog foods with different contents

ABSTRACT This study was aimed to evaluate and compare the nutrient digestibility of grain-inclusive and grain-free commercial dry dog foods using the method of total fecal collection and also explore their effects on fecal consistency. 21 different foods, including 14 grain-inclusive (7 grain-chicken meat, 7 grain-lamb meat) and 7 grain-free were investigated. 12 adult Golden retriever dogs (age 3-4 years, body weight=22.5±1.7kg) were divided into 3 groups. The results of digestibility trials indicated that the grain-lamb meat foods showed the highest digestibility of dry matter, organic matter, and crude fiber. Overall, in the grain-inclusive and grain-free group evaluation, grain-inclusive foods showed higher digestibility of crude fibers while grain-free foods had higher ether extract digestibility whereas the differences in the scores of fecal consistencies between the groups were insignificant. Contrary to popular belief, grain-inclusive foods were more digestive than grain-free foods in terms of dry matter and organic matter. There are studies involving starch sources in the dog food formulations, but there is a need to study the digestibility of complete dog food to supply them with adequate nutrients. Also, each diet should be assessed based on its overall nutrient profile and digestibility rather than individual ingredients.摘要 本研究旨在通过全粪便收集法（total fecal collection）评估并对比含谷物型（grain-inclusive）与无谷物型（grain-free）商品干性犬粮的营养消化率（nutrient digestibility），同时探究二者对粪便性状（fecal consistency）的影响。本研究共考察21款受试犬粮，其中含谷物型犬粮14款（7款为谷物-鸡肉配方，7款为谷物-羊肉配方），无谷物型犬粮7款。选取12只成年金毛寻回犬（年龄3~4岁，体重22.5±1.7kg），将其分为3组。消化率试验结果显示，谷物-羊肉配方犬粮的干物质（dry matter）、粗有机物（organic matter）与粗纤维（crude fiber）消化率最高。总体而言，在含谷物组与无谷物组的对比评价中，含谷物型犬粮的粗纤维消化率更高，而无谷物型犬粮的乙醚浸出物（ether extract）消化率更高；但各组间的粪便性状评分差异无统计学显著性。与大众普遍认知相悖的是，在干物质与粗有机物的消化率方面，含谷物型犬粮的表现优于无谷物型犬粮。现有部分研究已针对犬粮配方中的淀粉来源展开探讨，但仍需针对完整犬粮的消化率开展相关研究，以确保其能为犬只提供充足营养。此外，对每种日粮的评价应基于其整体营养组成（nutrient profile）与消化率，而非单一原料成分。