The mean serum level of vitamin A was significantly higher in the vitamin A supplemented infants than in the control infants on day @ ( @ + / - @ vs. @ +@ pmol / L , p < @ ) , day @ ( @ + / - @ vs. @ + / - @ micromol/L , p = @ ) and day @ ( @ + / - @ vs. @ + / - @ micromol/L , p < @ ) after vitamin A supplementation .