Thermoneutrality results in prominent diet-induced body weight differences in C57BL/6J mice, not paralleled by diet-induced metabolic differences.
METHODS
Mice are usually housed at 20-24 °C. At thermoneutrality (28 °C) larger diet-induced differences in obesity are seen. We tested whether this leads to large differences in metabolic health parameters.


RESULTS
We performed a 14-wk dietary intervention in C57BL/6J mice at 28 °C and assessed adiposity and metabolic health parameters for a semipurified low fat (10 energy%) diet and a moderate high fat (30 energy%) diet. A large and significant diet-induced differential increase in body weight, adipose tissue mass, adipocyte size, serum leptin level, and, to some extent, cholesterol level was observed. No adipose tissue inflammation was seen. No differential effect of the diets on serum glucose, free fatty acids, triacylglycerides, insulin, adiponectin, resistin, PAI-1, MMP-9, sVCAM-1, sICAM-1, sE-selectin, IL-6, ApoE, fibrinogen levels, or HOMA index was observed. Also in muscle no differential effect on mitochondrial density, mitochondrial respiratory control ratio, or mRNA expression of metabolic genes was found. Finally, in liver no differential effect on weight, triacylglycerides level, aconitase/citrate synthase activity ratio was seen.


CONCLUSIONS
Low fat diet and moderate high fat diet induce prominent body weight differences at thermoneutrality, which is not paralleled by metabolic differences. Our data rather suggest that thermoneutrality alters metabolic homeostasis.
Human and Animal Physiology, Wageningen University, Wageningen, The Netherlands.
Femke P M
FP
Hoevenaars
Melissa
M
Bekkenkamp-Grovenstein
Rolf J R J
RJ
Janssen
Sandra G
SG
Heil
Annelies
A
Bunschoten
Elise F
EF
Hoek-van den Hil
Sophie
S
Snaas-Alders
Katja
K
Teerds
Evert M
EM
van Schothorst
Jaap
J
Keijer
D000154:Aconitate Hydratase / Q000378:metabolism; D052242:Adiponectin / Q000097:blood; D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D001833:Body Temperature Regulation / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects*; D018752:Diet, Fat-Restricted; D059305:Diet, High-Fat; D004734:Energy Metabolism / Q000187:drug effects; D005227:Fatty Acids / Q000378:metabolism; D020738:Leptin / Q000378:metabolism; D008297:Male; D008810:Mice, Inbred C57BL; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism
D052242:Adiponectin; D005227:Fatty Acids; D020738:Leptin; D000154:Aconitate Hydratase
Adipose tissue function; Biomarkers; Metabolic health; Obesity; Serum parameters