engleski

Trans fatty acids in subcutaneous adipose tissue in brown bears in Croatia

In mammalian carnivores many dietary fatty acids (FA) are predictably incorporated into a consumer’s adipose tissue, since their ability to synthesize FA is limited. In some ecosystems, some FA are only available in a few types of food and can be used as a nutritional marker providing detailed information on animals feeding habits. Trans FA (tFA) may serve as useful biomarkers since they are incorporated into adipose tissue and they cannot be endogenously synthesized by carnivores. Trans FA are present in many commercially prepared food products and also in ruminants’ fats. The objective of this study was to evaluate human-bear relations using tFA. The study was conducted on 37 animals (20 M, 17 F). Thirty samples of subcutaneous adipose tissue were collected during the legal hunting season (March-May and September-December 2014) and 7 samples were collected following intervention shooting or after vehicle collision. After thawing, homogenization and lipid extraction, the FA composition was determined by gas chromatography/mass spectrometry. Results showed that lipids isolated from depot adipose tissues of brown bear were dominated by monounsaturated fatty acids (females 47.51±7.34%, males 51.15±12.06% ; the most common was oleic acid, cisC18:1). Saturated fatty acids constituted 26.92±14.76% in females and 29.86±12.39% in males ; palmitic acid (C16) was found in the highest percentage. Polyunsaturated fatty acids (PUFA) were found in 25.56±12.21% (females) and 18.99±11.45% (males) ; the most common was linoleic acid (C18:2). Higher percentage of C17:0, C18:2 and PUFA were found in females in comparison to males. Percentage of tFA in subcutaneous fat showed no differences between hunted bears and the ones that died of other reasons, but interestingly tC18:1was found in all bears (females 2.76±1.48%, males 3.09±1.26%). Free- ranging bears may obtain tFA from different dietary sources but the predominant source of tC18:1 is processed human food (hydrogenated vegetable oil found in many processed foods) which also contains tC18:1 in higher percentage than ruminant’s fat. Further research should be focused on determination which C18:1 isomers are predominant in subcutaneous adipose tissue of brown bear in Croatia. Results could help in bear management strategies.

trans fatty acids ; subcutaneous adipose tissue ; brown bear

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