Pigs were reared via two management schemes to create a moderate and high level of antigen exposure in the pigs. In each antigen exposure group, pigs were self-fed one of five dietary concentrations of a group of five B vitamins (niacin, pantothenic acid, riboflavin, B12, and folacin) from 22 to 61 pounds body weight. Bioavailable concentrations of the vitamins equivalent to 70, 170, 270, 370, and 470% of the current estimated need (NRC, 1988) for 11 to 22 pound pigs were provided. Pigs experiencing a moderate versus high level of antigen exposure consumed more feed (+.54 lb/day) and gained more body weight (.32 lb/day) but required similar amounts of feed per unit of gain (-.03).

Dietary B vitamin additions at concentrations above current estimated requirements (NRC, 1988) resulted in up to 21 and 19% faster body growth rates and 10 and 6% less feed required per unit of gain in pigs experiencing a moderate and high level of antigen exposure, respectively. Based on these data, dietary concentrations of one or more of the test B vitamin equivalent to 370% of the current estimated needs (NRC, 1988) are required to optimize rate and efficiency of growth in 20 to 60 pound pigs experiencing a moderate or high level of antigen exposure.