Herdt T H
Nutrition Section, Michigan State University, East Lansing, USA.
Vet Clin North Am Food Anim Pract. 2000 Jul;16(2):387-403. doi: 10.1016/s0749-0720(15)30111-0.
Nutritional assessment based on animal response factors is the basis of essentially all dietary recommendations. Blood concentrations of nutrients, metabolites, and hormones are important animal response factors associated with nutriture, making blood analysis an important nutritional assessment technique. There are, however, numerous sources of variability, other than nutrition, affecting the concentration of blood analytes used in nutritional assessment. Minimizing the effects of non-nutrient sources of variability and maximizing the effects of nutritional variability is the objective in designing strategies for blood sampling and testing for nutritional assessment. Important non-nutrient sources of variability are age, sex, gestation stage, lactation stage and milk yield, and season. When interpreting test results, grouping animals by these characteristics is an important means of minimizing the effects of non-nutritional variability. Within these groups, it is important to take an adequate number of samples, generally starting out with at least seven. Finally, selecting appropriate tests is critical. Tests commonly used for clinicopathologic evaluations are not necessarily the best tests for nutritional assessment. Analytes should be chosen that are likely to have a large portion of their total variability caused by nutritional effects. This generally does not include those metabolites the blood concentrations of which are rigidly controlled by homeostatic forces.
基于动物反应因素的营养评估是几乎所有饮食建议的基础。血液中营养物质、代谢产物和激素的浓度是与营养状况相关的重要动物反应因素，这使得血液分析成为一种重要的营养评估技术。然而，除营养因素外，还有许多变异性来源会影响用于营养评估的血液分析物的浓度。在设计用于营养评估的血液采样和检测策略时，目标是尽量减少非营养性变异性来源的影响，并最大限度地提高营养变异性的影响。重要的非营养性变异性来源包括年龄、性别、妊娠阶段、泌乳阶段和产奶量以及季节。在解释检测结果时，按这些特征对动物进行分组是尽量减少非营养性变异性影响的重要方法。在这些组内，采集足够数量的样本很重要，一般至少从七个样本开始。最后，选择合适的检测至关重要。常用于临床病理评估的检测不一定是营养评估的最佳检测。应选择那些其总变异性很大一部分可能由营养效应引起的分析物。这通常不包括那些血液浓度受稳态力量严格控制的代谢产物。
