Consequences of maternal omega-3 polyunsaturated fatty acid supplementation on respiratory function in rat pups.

Most pre-term infants present respiratory instabilities and apnoeas as a result of incomplete development of the neural circuits that control breathing. Because omega-3 polyunsaturated fatty acids (n-3 PUFA) benefit brain development, we hypothesized that n-3 PUFA supplementation (via the maternal diet) improves respiratory function in rat pups. Pups received n-3 PUFA supplementation from an enriched diet (13 g kg-1 of n-3 PUFA) administered to the mother from birth until the experiments were performed (postnatal days 10-11). Controls received a standard diet (0.3 g kg-1 of n-3 PUFA). Breathing was measured in intact pups at rest and during hypoxia (FiO2  = 0.12; 20 min) using whole body plethysmography. The duration of apnoeas induced by stimulating the laryngeal chemoreflex (LCR) was measured under anaesthesia. Lung morphology was compared between groups. Maternal n-3 PUFA supplementation effectively raised n-3 PUFA levels above control levels both in the blood and brainstem of pups. In intact, resting pups, n-3 PUFA increased the frequency and duration of apnoeas, especially in females. During hypoxia, n-3 PUFA supplemented pups hyperventilated 23% more than controls; their anapyrexic response was 1 °C less than controls. In anaesthetized pups, n-3 PUFA shortened the duration of LCR-induced apnoeas by 32%. The relative pulmonary surface area of n-3 PUFA supplemented pups was 12% higher than controls. Although n-3 PUFA supplementation augments apnoeas, there is no clear evidence of deleterious consequences on these pups. Based on the improved lung architecture and responses to respiratory challenges, this neonatal treatment appears to be beneficial to the offspring. However, further experiments are necessary to establish its overall safety.