Abstract:

This study aimed to gain insight into the influence of storage time and temperature on fatty acid (FA) signatures of biopsies of marine mammal adipose/blubber tissues. To examine storage effects, biopsy-type slices from larger pieces of adipose tissues from 2 polar bears Ursus maritimus were stored at either –20 or –80°C and subsequently analyzed for fatty acid composition initially (before storage), after 4 yr, and after 9 yr. At –20°C, after both 4 and 9 yr, proportions of polyunsaturated FAs significantly decreased, and proportions of monounsaturated FAs increased. Proportions of saturated FAs significantly increased only after 9 yr at –20°C in samples of 1 individual. After 4 and 9 yr of storage at –80°C, proportions of the 3 FA classes did not significantly change overall. Intra-individual differences in FA proportions increased over time in –20°C conditions, further pointing to biases stemming from inadequate storage conditions. These findings support the need to store biopsied fatty tissues (or other similarly thin and/or small adipose/ blubber samples) at or below –80°C to adequately preserve FA signatures in samples over time for retrospective applications such as dietary studies.

https://doi.org/10.3354/meps14501