Meeting Abstract

62.3  Friday, Jan. 6  Pre-hibernation saturated fat rich diet in the subtropical mouse-tailed bat (Rhinopoma microphyllum) with relation to hypothalamic NPY and AgRP expression LEVIN, Eran*; YOM-TOV, Yoram; HEFETZ , Abraham; KRONFELD-SCHOR, Noga; Tel-Aviv University, Department of Zoology; Tel-Aviv University, Department of Zoology; Tel-Aviv University, Department of Zoology; Tel-Aviv University, Department of Zoology levinere@post.tau.ac.il

Prior to hibernation, mammals accumulate large amounts of fat in their bodies. The saturation of fatty acids (FA) in both white adipose tissue (WAT) and membrane phospholipids of mammals often reflect their diet composition. In temperate mammalian species, hibernation is improved by increasing the levels of poly-unsaturated fatty acids (PUFA) in their body fat by alternating to a PUFA rich diet. In this field study we found that the greater mouse-tailed bat accumulates large amounts of fat at the end of summer by switching to a fat-rich diet (queen carpenter ants, Camponotus felah). PUFA are almost absent in this diet, which instead contains a high fraction of saturated fatty acids and mono-unsaturated fatty acids . We found similar low levels of PUFA in mouse-tailed bats' WAT, but not in their heart total lipids. The expression of two appetite stimulating (orexigenic) hypothalamic neuropeptides, AgRP and NPY, increased in parallel to the shift in diet and fat-gain of the mouse-tailed bats. We hypothesize that the increased expression level of these neuropeptides may be triggered by photoperiod and contribute to the diet shift and weight gain. This is the only known example of specific pre-hibernation diet in bats, and constitutes the most saturated fatty acid composition ever documented in a mammal. We suggest that this composition is an adaptation for hibernation at the relatively high ambient temperature (around 20°C), that we recorded in mouse-tailed bat hibernaculas.