家犬品种中常量营养素选择的几何分析

Although many herbivores and omnivores have been shown to balance their intake of macronutrients when faced with nutritionally variable foods, study of this ability has been relatively neglected in carnivores, largely on the assumption that prey are less variable in nutrient composition than the foods of herbivores and omnivores and such mechanisms therefore unnecessary. We performed diet selection studies in 5 breeds of adult dog (Canis lupus familiaris) to determine whether these domesticated carnivores regulate macronutrient intake. Using nutritional geometry, we show that the macronutrient content of the diet was regulated to a protein:fat:carbohydrate ratio of approximately 30%:63%:7% by energy, a value that was remarkably similar across breeds. These values, which the analysis suggests are dietary target values, are based on intakes of dogs with prior experience of the respective experimental food combinations. On initial exposure to the diets (i.e., when naive), the same dogs self-selected a diet that was marginally but significantly lower in fat, suggesting that learning played a role in macronutrient regulation. In contrast with the tight regulation of macronutrient ratios, the total amount of food and energy eaten was far higher than expected based on calculated maintenance energy requirements. We interpret these results in relation to the evolutionary history of domestic dogs and compare them to equivalent studies on domestic cats.

虽然许多草食动物和杂食动物在面对营养多变的食物时能够平衡它们对大量营养素的摄取，但对肉食动物这种能力的研究相对被忽视，主要是因为一般认为猎物的营养成分比草食和杂食动物的食物变化小，因此研究捕食者的取食的这种机制是不必要的。我们对5个品种的成年犬(Canis lupus familiaris进行了饮食选择研究，以确定这些驯养的肉食动物是否调节了大量营养素的摄入。利用营养几何学，我们表明，膳食中的常量营养素含量被能量调节到大约30%：63%：7%的蛋白质：脂肪：碳水化合物的比例，这个值在不同品种之间非常相似。分析表明，这些值是饮食目标值，是基于狗的摄入量，这些狗之前对各自的实验食物组合有过经验。在最初接触这些饮食时(即幼年的时候)，同样的狗自己选择了脂肪虽然略低但明显较低的饮食，这表明学习在大量营养素调节中发挥了作用。与对大量营养素比例的严格监管形成对比的是，根据计算的维持（生存）所需能量需求，食物和能量的总摄入量远远高于预期。我们解释了这些结果与家犬进化史的关系，并将它们与家猫的同等研究进行了比较。

原文

Hewson-Hughes, A. K., Hewson-Hughes, V. L., Colyer, A., Miller, A. T., McGrane, S. J., Hall, S. R., . . . Raubenheimer, D. (2012). Geometric analysis of macronutrient selection in breeds of the domestic dog, Canis lupus familiaris. Behavioral Ecology, 24(1), 293-304. doi: 10.1093/beheco/ars168