Long chain 20-22C polyunsaturated fatty acids (FA) play a role in modulating the structure and function of neural membranes. We previously reported that pups of dams fed fish oil supplemented diets had longer ABCTs compared with pups of dams fed corn oil supplemented diets. In the present study, the effect of different levels of maternal dietary DHA upon rat pup ABCTs was investigated. Methods: Dams were fed, beginning on day 2 of gestation and throughout lactation, a purified diet whose fat source (22% of cals) was a vegetable oil blend supplemented with a single cell algae oil containing 1 of 3 different concentrations of DHA (5 dams/grp). Final DHA concentrations in maternal diets were 2%, 4% or 6% of total FA; concentrations of all other FA were identical. On postnatal (pnd) 3, pups were culled to 10/dam and were randomly cross fostered among dams of the same diet group to control for litter effects. Milk from culled pup stomachs was used for FA analysis. ABCTs were recorded on pnd 23 and 29 (10-20 pups/diet group). On pnd 29 pups were sacrifiiced and brains were removed for FA analysis.Results: Maternal and pup weights and weight gains were not different among diet groups. The FA composition of dam milk and pup tissues reflected maternal diet. Dam milk and pup brain arachidonic (AA) and DHA levels generally demonstrated a reciprocal relationship. ABCTs were longer in pups of dams fed the higher levels of DHA, suggesting a slower rate of myelination. Concl: High levels of DHA may affect neural development as measured by the speed of conduction through the brainstem auditory pathway. Table

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Funded in part by Ross Products Division, Abbott Laboratories