engleski

Trans fatty acids as potential assessment tool for anthropogenic foraging by brown bears in Croatia

In most animals trans fatty acids (tFA) originate from the diet. Two major dietary sources for tFA include partially hydrogenated vegetable oils in processed food products and ruminant’s meat, dairy products and milk. Industrially processed food can contain up to 50% of tFA, with elaidic acid (t9-C18:1) as predominant. In contrast, ruminant fats generally have lower quantities of tFA (1–8%), with vaccenic acid (t11-C18:1) being the main isomer. The objective of this study was to determine the presence of C18:1t isomers in subcutaneous adipose tissue of brown bears in Croatia. The study was conducted on 103 animals (26 females, F ; 77 males, M). Ninety-two samples were collected during the legal hunting season (March-May and SeptemberDecember 2014), one after illegal hunting, and 12 s following interventional shooting or after vehicle collision. Tissue samples were homogenized and total lipids extracted. The FA composition was determined by gas chromatography. Results showed that lipids isolated from depot adipose tissues of brown bears were dominated by monounsaturated fatty acids (F, 50.35±7.65% ; M, 50.93±8.34% ; the most common FA in F was oleic acid, c9-C18:1 (19.59±6.33%), while the most common FA in M was elaidic acid, t9-C18:1, (19.36±11.96%). Saturated fatty acids constituted 28.93±10.05% in F and 30.37±8.34% in M. The ratio of polyunsaturated fatty acids was 20.72±12.50% (F) and 18.34±10.71% (M). A signifcantly higher percentage of t11-C18:1 was determined in samples from hunted bears and bears that died of vehicle collision (N=98) compared to bears that died after intervention shooting (N=5). A higher percentage of t9-C18:1 was found in bears that died after intervention shooting compared to hunted bears and bears that died of vehicle collision, although the difference was not signifcant. The predominant source of t9-C18:1 is processed human food, and such bear behavior can result in more frequent bear-human conflict. Further research should be focused on larger sample size of bears that died after intervention shooting. Those results could provide help in the development of bear management strategies.

trans fatty acids, antropogenic feeding, brown bear

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