PERINATAL SUPPLY OF OMEGA-3 FATTY ACIDS PROGRAMS CORE BODY TEMPERATURE LATER IN LIFE

Adrian D. Pearce, Nora Chen, Richard S. Weisinger, Andrew J. Sinclair, Harrison S. Weisinger, Laboratory for Neuroscience of Development and Disease, Section of Neurobiology, Howard Florey Institute, University of Melbourne, 3010, Victoria, Australia.

Background: Perturbations in the intra-uterine or perinatal environment have the potential to profoundly affect development, and consequently impact upon adult function. Omega-3 fatty acids are the predominant fatty acids within the nervous system, with significant accretion occuring in the perinatal period. Perinatal intake of omega-3 PUFA appears to affect several fundamental physiological processes, such as the regulation of fluid and osmotic balance, blood pressure and energy homeostasis; all of which have important connections within or near the hypothalamus. Given that the regulation of core body temperature (CBT) is known to be orchestrated by the hypothalamus, we sought to determine whether CBT is altered by dietary omega-3 fatty acid manipulation in the perinatal period.

Methods: Female Sprague-Dawley rats were mated and maintained on diets deficient (DEF) or sufficient (control, CON) in omega-3 PUFA. Diets contained identical amounts of protein, carbohydrate, vitamins and minerals, plus 10% isocaloric fat; DEF, omega-6 PUFA-rich safflower oil; CON, safflower oil and omega-3 PUFA-rich flaxseed oil. Offspring (n=24) from these rats were fed the same diet as their dams through breast-milk until weaning (3 weeks of age). At this time (n=6), and again at 9 weeks of age (n=6), rats were switched from DEF to CON (i.e. DEF-CON3 and DEF-CON9, repectively). Remaining animals (n=6 per group) were maintained on their original diets (i.e. CON-CON; DEF-DEF). Food intake, body weight, locomotor activity (radiotelemetry) and CBT (colorectal thermocouple) were measured.

Results: Animals initially receiving DEF had lower CBTs than the animals raised and maintained on CON diet (i.e. CON-CON, 37.1 ± 0.1°C vs. DEF-CON3, 36.4± 0.2°C; DEF-CON9, 36..3 ± 0.1°C; DEF-DEF, 36.1 ± 0.1°C; P<0.01). There was no difference in CBT between animals that initially received DEF, nor were there differences between any of the groups in other parameters.

Conclusion: Perinatal omega-3 PUFA deficiency was associated with a reduction in CBT, regardless of the contemporary diet. Changes in body weight, caloric intake and activity do not explain these observations.