Effect of Housing Temperature on Body Composition in Laboratory Mouse

Development of obesity and associated disorders is caused by imbalance between energy intake and energy expenditure. Significant part of energy expenditure can be represented by energy cost of maintaining stable body temperature. In this thesis, the effect of thermoneutrality and high fat feeding on body composition was characterized in female C57BL/6 mice. These mice were housed either at 22 řC (standard temperature) or at 30 řC (thermoneutrality) and fed by standard chow or high fat diet for 13 weeks. Energy intake of chow-fed thermoneutral animals was lowered in comparison to mice housed at standard temperature, reflecting lower energy cost of thermogenesis. This reduction of food intake was prevented by high fat feeding resulting in adipose tissue accumulation in particular in high fat-fed thermoneutral animals. While studying this model, protocol for assessment of body composition using newly acquired dual energy X-ray absorptiometry system was validated. Reflecting the development of obesity, glucose and lipid homeostasis was deteriorated in these mice. In line with earlier notions in literature describing male mice, our data suggest critical importance of housing temperature in efficiency of high fat feeding even in female mice. Keywords: thermoneutrality, obesity, body composition, DEX