The effects of poly-unsaturated fatty acids on the physiology of hibernation in a South American marsupial, Dromiciops gliroides

Published Date

November 2014, Vol.177:62–69, doi:10.1016/j.cbpa.2014.07.004

Title 

The effects of poly-unsaturated fatty acids on the physiology of hibernation in a South American marsupial, Dromiciops gliroides

• Author 

• Carolina Contreras ^a
• Marcela Franco ^b
• Ned J. Place ^c
• Roberto F. Nespolo ^a,d,,

• aInstituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Casilla 567, Campus Isla Teja, Valdivia 5090000, Chile
• bFacultad de Ciencias Naturales y Matemáticas, Universidad de Ibagué, Carrera 22 Calle 67 Barrio Ambalá, Ibagué, Tolima, Colombia
• cDepartment of Population Medicine & Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
• dCenter of Applied Ecology and Sustainability (CAPES)

Received 21 April 2014. Revised 24 June 2014. Accepted 3 July 2014. Available online 15 July 2014.

Abstract

Many mammals hibernate, which is a profound lethargic state of several weeks or months during winter, that represents a transitory episode of hetherothermy. As with other cases of dormancy, the main benefit of hibernation seems to be energy saving. However, the depth and duration of torpor can be experimentally modified by the composition of food, especially by fattyacid composition. In eutherians, diets rich in unsaturated fatty acids (i.e., fatty acids with at least one double bond) lengthen torpor, reduce metabolism and permit hibernation at lower temperatures. Here we studied whether diets varying in fatty acid composition have an effect on the physiology of hibernation in a South American marsupial, Dromiciops gliroides. We designed a factorial experiment where thermal acclimation (two levels: natural versus constant temperature) was combined with diet acclimation: saturated (i.e., diets with high concentration of saturated fatty acids) versus unsaturated (i.e., diets with high concentration of unsaturated fatty acids). We measured energy metabolism in active and torpid individuals, as well as torpor duration, and a suite of 12 blood biochemical parameters. After a cafeteria test, we found that D. gliroides did not show any preference for a given diet. Also, we did not find effects of diet on body temperature during torpor, or its duration. However, saturated diets, combined with high temperatures provoked a disproportionate increase in fat utilization, leading to body mass reduction. Those animals were more active, and metabolized more fats than those fed with a high proportion of unsaturated fatty acids (=“unsaturated diets”). These results contrast with previous studies, which showed a significant effect of fatty acid composition of diets on food preferences and torpor patterns in mammals.

Keywords

Dromiciops

Hibernation

Poly-unsaturated fatty acids

South American marsupial

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  Corresponding author.

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