Department of Animal Science, College Station, TX, USA 77843-2471.
Front Biosci (Landmark Ed). 2014 Jun 1;19(6):967-85. doi: 10.2741/4261.
Development of obesity in animals is affected by energy intake, dietary composition, and metabolism. Useful models for studying this metabolic problem are Sprague-Dawley rats fed low-fat (LF) or high-fat (HF) diets beginning at 28 days of age. Through experimental design, their dietary intakes of energy, protein, vitamins, and minerals per kg body weight (BW) do not differ in order to eliminate confounding factors in data interpretation. The 24-h energy expenditure of rats is measured using indirect calorimetry. A regression model is constructed to accurately predict BW gain based on diet, initial BW gain, and the principal component scores of respiratory quotient and heat production. Time-course data on metabolism (including energy expenditure) are analyzed using a mixed effect model that fits both fixed and random effects. Cluster analysis is employed to classify rats as normal-weight or obese. HF-fed rats are heavier than LF-fed rats, but rates of their heat production per kg non-fat mass do not differ. We conclude that metabolic conversion of dietary lipids into body fat primarily contributes to obesity in HF-fed rats.
动物肥胖的发展受能量摄入、饮食成分和代谢的影响。研究这一代谢问题的有用模型是 28 天大的 Sprague-Dawley 大鼠，它们开始喂食低脂肪（LF）或高脂肪（HF）饮食。通过实验设计，它们每公斤体重（BW）的能量、蛋白质、维生素和矿物质的饮食摄入量没有差异，以消除数据解释中的混杂因素。使用间接测热法测量大鼠的 24 小时能量消耗。构建回归模型，根据饮食、初始 BW 增益和呼吸商和产热的主成分得分，准确预测 BW 增益。使用混合效应模型分析代谢（包括能量消耗）的时程数据，该模型适合固定和随机效应。聚类分析用于将大鼠分类为正常体重或肥胖。HF 喂养的大鼠比 LF 喂养的大鼠重，但每公斤非脂肪质量的产热量速率没有差异。我们得出结论，膳食脂质向体脂肪的代谢转化主要导致 HF 喂养的大鼠肥胖。
