Effect of time on neonatal immune response to dietary selenium and fat

The effect of dietary selenium (0.03 mg/kg and 0.31 mg/kg), and fat (5% and 20% corn oil) on antibody formation in the neonatal rat was studied at two different time periods using four diets. The latter were fed to dams throughout pregnancy and lactation and to their pups starting at day 18. A week later, pups received intraperitoneal injections of the test antigen, fluorescein-bovine serum albumin in complete Freund's adjuvant (150 micrograms per 30 g body wt.). On days 7 or 9 post-injection, the pups were sacrificed. The antibody titer, as determined by the quenching of fluorescein by the test sera, and by ELISA, almost doubled from day 7 to day 9 (p < 0.05). There was no significant difference in antibody titers between dietary groups except at day 9 post-injection. Using ELISA, pairwise comparisons indicated that addition of 0.3 mg/kg Se to high fat diet was associated with low antibody titer (p < 0.05).