Decreasing Traits of Fecal Immunoglobulin A in Neonatal and Weaning Piglets

The concentration of fecal secretory immunoglobulin A (sIgA) in neonate and weaning piglets was measured daily from 1 day after birth to 50 days of age. The concentration of fecal sIgA started from the level of 104 μg/g wet feces 1 day after birth and then increased to a maximal value of up to 105 μg/g within a few days of birth. The values constantly declined to between 101 and 102 μg/g for the next 10 days and were relatively constant until weaning. The level of sIgA in the feces remained very low until at least 50 days of age. The vulnerability of pre- or post-weaning piglets can be explained, at least in part, by this low level of sIgA in the intestine.