Abstract 197 - Arachidonic and docosahexaenoic fatty acids in brown bears brain tissue
Slaven Reljić, University of Zagreb, Croatia, Faculty of Veterinary Medicine, University of Zagreb, Croatia ProfessionalSalon 8/9
Lana Pađen, Agnieszka Sergiel, Djuro Huber, Slaven Reljić, Ivan Berečki, Jasna
Aladrović
The conditionally essential polyunsaturated fatty acids (PUFA), arachidonic acid (AA, 20:4n-6)
and docosahexaenoic acid (DHA, 22:6n-3) are predominant n-6 and n-3 PUFA in the mammalian
central nervous system. Since AA and DHA, as well as their respective shorter-chain precursors,
linoleic acid (LA, 18:2n-6) and α-linolenic acid (α-LNA, 18:3n-3), cannot be synthesized de novo,
they must be obtained from diet. The main sources of these for the wild brown bear are various
berries and nuts. Adequate brain concentrations of AA and DHA and interactions among them
and their metabolites are important for brain structure, function, and metabolism. The
amounts of AA and DHA, and whether they are changing seasonally in brown bears brain are
unknown. We aimed at determining FA using samples collected from 36 free-ranging brown
bears (11 females, 25 males) in Croatian part of Dinaric-Pindos population range during spring
and autumn in 2022 and 2023, while attending to human-induced mortalities. Samples of
medulla or pons regions were homogenized, total lipids extracted, and composition of FA was
determined by gas chromatography. Brain tissue in females and males comprised 6.1±2% vs.
4.8±2.1% AA and 7.7±3.8% vs. 7.2±3.8% DHA, respectively. Females in spring 2022 had
significantly lower levels of LA (4.95±0.06% vs. 10.9±1.8%) than in autumn samples of the same
year. Females in autumn 2022 had significantly higher level of DHA (11.4±2.2% vs. 5.4±2.2%)
than the same season in 2023. Male spring samples in 2022 had significantly higher LA
(8.6±3.6% vs. 2.2±2.6%) and DHA (8.7±3.5% vs. 4.9±2.6%) and significantly lower α-LNA
(1.0±0.6% vs. 1.6±0.6%) and AA (3.2±1.2% vs. 6.4±2.0%) than males in the same season in 2023,
while significantly lower AA (3.9±0.9% vs. 6.3±1.7%) in autumn 2022 than in 2023. This
preliminary study suggests that season, especially autumn period with hyperphagia, affects AA
and DHA levels and underline the importance of natural foods.
