Olfactory discrimination deficits in n-3 fatty acid-deficient rats.

Docosahexaenoic acid (DHA), a long chain n-3 fatty acid, is present in high concentrations in the central nervous system. Although the role that DHA may play in neural function is not well understood, infants fed formulas containing low levels of n-3 fatty acids have decreased visual acuity and neurodevelopmental test scores. The present experiment assessed whether dietary manipulations that decrease the concentration of DHA in the brain interfered with olfactory-based learning. We fed rats a diet that provided adequate n-3 fatty acids or a diet that was deficient in n-3 fatty acids for two generations. The second generation n-3-deficient group had 81% less brain DHA (82% less in olfactory bulb) compared to the n-3-adequate group and made significantly more errors in a series of olfactory-cued, 2-odor discrimination tasks compared to the adequate group. These results suggest that lower levels of central nervous system DHA lead to poorer performance in a series of simple odor discrimination tasks.