Estimating nutrient intake in comparative studies of animals: an example using dietary carotenoid content in birds
Estimating nutrient intake in comparative studies of animals: an example using dietary carotenoid content in birds
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在动物比较研究中估算营养摄入量：以鸟类膳食类胡萝卜素含量为例
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发表时间：
2006
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通讯作者：
V. Olson
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作者：
V. Olson
许多不同的方法报告动物饮食已被用于生态研究。这些在准确度和精确度方面差异很大，因此在广泛的分类群中测量和比较饮食以及这些饮食中营养素的数量的尝试变得复杂。对于大多数鸟类来说，饮食中的类胡萝卜素含量还没有直接测量。因此，在这里，我用一个鸟类的例子来说明如何不同的方法来测量饮食中各种食物的数量影响的相对排名较高的类群（家庭，亚科，部落），和这些类群中的物种，关于他们的饮食中的类胡萝卜素含量。这是一个及时的例子，因为最近的鸟类文献都集中在饮食类胡萝卜素可能在生存，健身和信号方面进行权衡。我评估了平均膳食类胡萝卜素含量的代表性的30个较高类群的鸟类使用四种不同的类胡萝卜素摄入量指数不同的精度，包括营养水平，粗尺度和细尺度的分类指数，和定量估计的膳食类胡萝卜素。最后一种方法被用作基准。对于类群之间的比较，所有，但营养级指数显着相关。然而，对于类群内物种的比较，细尺度指数优于粗尺度指数，这反过来又优于营养级指数。此外，每种方法都有优点和缺点，以及必须考虑的基本假设。对几种可能的饮食评估方法进行检查和比较似乎突出了这些方法，以便在现有数据的情况下使用最佳指数，并建议在任何统计分析中纳入估计的营养摄入量之前采取这一步骤。虽然适用于鸟类类胡萝卜素在这里，这种方法可以很容易地适用于其他类群和类型的营养素。
Many different methods of reporting animal diets have been used in ecological research. These vary greatly in level of accuracy and precision and therefore complicate attempts to measure and compare diets, and quantitites of nutrients in those diets, across a wide range of taxa. For most birds, the carotenoid content of the diet has not been directly measured. Here, therefore, I use an avian example to show how different methods of measuring the quantities of various foods in the diet affect the relative rankings of higher taxa (families, subfamilies, and tribes), and species within these taxa, with regard to the carotenoid contents of their diets. This is a timely example, as much recent avian literature has focused on the way dietary carotenoids may be traded off among aspects of survival, fitness and signalling. I assessed the mean dietary carotenoid contents of representatives of thirty higher taxa of birds using four different carotenoid intake indices varying in precision, including trophic levels, a coarse-scale and a fine-scale categorical index, and quantitative estimates of dietary carotenoids. This last method was used as the benchmark. For comparisons among taxa, all but the trophic level index were significantly correlated with each other. However, for comparisons of species within taxa, the fine-scale index outperformed the coarse-scale index, which in turn outperformed the trophic level index. In addition, each method has advantages and disadvantages, as well as underlying assumptions that must be considered. Examination and comparison of several possible methods of diet assessment appears to highlight these so that the best possible index is used given available data, and it is recommended that such a step be taken prior to the inclusion of estimated nutrient intake in any statistical analysis. Although applied to avian carotenoids here, this method could readily be applied to other taxa and types of nutrients.