Developmental omega-3 supplementation improves motor skills in juvenile-adult rats

Long-chain polyunsaturated fatty acids are critical for brain growth spurt during both foetal and postnatal period. They play important roles in the expression of genes regulating cell differentiation and neuronal growth, as well as in the development of synaptic processing of neural cell interaction. Foetus and placenta are dependent on maternal supply for their growth and development, and supplemented infants show significantly greater mental and psychomotor scores. In particular, it has been shown that if mothers take omega-3 supplements, their babies are smarter and better physically coordinated. On these grounds, the aim of the present study was to investigate, in the Sprague–Dawley rat, the effects of perinatal treatment with omega-3 on motor activity, motor coordination, motor learning and memory. From gestational day 8 throughout the lactation period, dams received either an emulsion of 0.05 g/kg body weight omega-3 in fruit juice, or an emulsion of 1 g/kg body weight omega-3 in fruit juice or just the fruit juice (control). Omega-3 formula was made of 27% docosahexaenoic acid and 53% eicosapentaenoic acid. On the day of birth (postnatal day 1), all pups were weighed, and then randomly culled to eight pups per litter. Pups were weaned at 21 days of age. One male pup per litter from each litter (control, n = 6; omega-3 0.05 g/kg, n = 5; omega-3 1 g/kg, n = 6) was used. Both control and treated rats were tested for (i) locomotor activity using the open field paradigm, (ii) motor coordination and motor learning using the rotarod/accelerod task and (iii) memory using the passive avoidance paradigm. Rats were tested on postnatal day 21 and re-tested on postnatal day 90. As a result, docosahexaenoic acid and eicosapentaenoic acid supplementation significantly improved motor coordination. In particular, the latency to fall at the first speed was significantly increased in the treated rats as compared to the control animals. This benefit was observed with both doses at each tested age. The rat performance in accelerating rotation speed mode, which provides an indication of motor learning ability, was not modified by the omega-3 supply. Finally, the omega-3 treatment did not influence motor activity in the open field-tested rats, nor the memory ability in the passive avoidance task. In conclusion, perinatal omega-3 supplementation exerts a long lasting beneficial effect on the rotarod performance indicating improvement in balance and motor coordination and, possibly, in the functioning of pathways governing this task.