Omega-3 diets reduce swimming-test immobility after maternal high-fat feeding in rats
A peer-reviewed rat experiment found less swimming-test immobility after post-weaning diets enriched with DHA or EPA. The offspring’s mothers had received high-fat food during pregnancy and nursing. Brain measurements also showed partial, sex-dependent changes in myelin-related markers. The behavioural finding is an animal-test result, with no established human treatment benefit or proven causal link between myelin changes and behaviour.
Science··Morning
The diet starts after weaning
The rat experiment separated maternal feeding from the offspring’s later diet. Mothers received standard or high-fat food during pregnancy and nursing. After weaning, offspring were given standard food or food containing DHA or EPA, two omega-3 fatty acids, before behavioural testing in adulthood.[1]
Researchers tested females and males and measured tissue in the prefrontal cortex, a front-brain region. The study examined both behaviour and markers related to myelin, the insulating material around nerve fibres. That design allowed comparison of dietary groups within each sex.[1]
Less immobility in the swimming test
Offspring of high-fat-fed mothers showed more immobility in a forced-swimming test. After DHA- or EPA-enriched feeding, that measure moved towards the standard-diet controls in both sexes. The researchers also assessed swimming, climbing and general activity rather than relying only on immobility.[1]
Immobility is an animal behavioural measure used to study depressive-like responses, not a clinical diagnosis of depression. The experiment provides no human treatment result. A causal connection between the myelin-related changes and the behavioural difference was not established.[1]
Brain markers differ by sex and fatty acid
Recovery in myelin-related gene and protein measurements was partial and differed between females and males. In males, EPA showed broader changes in measured proteins and myelin-producing cells than DHA. Improvements in gene measurements did not uniformly extend to protein measurements in females.[1]
The study did not measure fatty-acid concentrations in blood or brain. Further behavioural tests and measurements in other brain regions would be needed to extend the result. Its demonstrated dietary effect remains the change in swimming-test immobility in these rats, alongside uneven changes in brain markers.[1]
