Quantitative Analysis of Three Classes of Immunoglobulins in Serum of Newborn Pigs and Milk of Sows

SUMMARY The chronologic variation of serum concentrations of immunoglobulins (Ig) G (IgG), A (IgA), and M (IgM) was studied in newborn pigs orally or subcutaneously given an immunosubstance such as dry serum and γ-globulin other than colostrum. In the control hysterectomy-produced colostrum-deprived (hpcd) newborn pigs, a slight amount of IgG was observed in the serum at 2 days of age, but disappeared at 5 days; it reappeared at 12 days and increased after that. IgM and IgA were detected in the pigs at 9 and 16 days of age, respectively, and increased thereafter. There was a slightly greater concentration of IgM than of IgA in the pigs up to 23 days; after that, there was a greater concentration of IgA than of IgM. After 30 days, IgG increased more rapidly than did IgA and IgM. The greatest concentration of each class of Ig administered passively was seen 24 hours after administration. The smallest concentration of IgG was seen after the 24th postadministration hour in newborn pigs orally given dry serum or colostrum at 21 or 28 days of age. (The smallest concentration was 4.9 and 4.0 times smaller than the greatest concentration in dry serum-fed and colostrum-fed newborn pigs, respectively.) Then IgG concentration tended to increase, although the difference between the greatest and the smallest concentrations was large. In contrast, in the newborn pigs subcutaneously injected with γ-globulin, the smallest concentration of IgG (approx 1.7 times smaller than the greatest concentration) was seen at 7 days of age, which was earlier than in dry serum-fed and colostrum-fed pigs. Then, IgG concentration increased gradually, but the difference between the greatest and smallest concentrations was small. When IgA and IgM values were compared, the IgA was temporarily smaller than the IgM but then became greater than it, although there was only a small chronologic difference between them. Dry serum given to hpcd pigs contained twice as much IgA as IgM. Nevertheless, the greatest concentration of IgA in serum was approximately 1.9 times smaller than the concurrent concentration of IgM in the dry serum-fed pigs in the early period after dry-serum feeding. However, the greatest concentration of IgA was approximately 2.5 times greater than the concurrent concentration of IgM in the colostrum-fed pigs. In whey of sow's milk, the concentration of each class of Ig was several times greater than that in normal porcine serum during the period from the day before parturition to 3 days after parturition; the concentrations decreased rapidly after that. There were, however, differences in manner of decrease among the classes of Ig; i.e., the smallest concentration of IgG and IgA was seen at the 5th postpartum day. After this, the concentrations increased a little and remained almost the same after postpartum day 12, at which time IgG in whey was at the same concentration as that in normal serum, but IgA in whey was approximately 3 times greater than that in normal serum. After postpartum day 14, IgM could not be detected in whey.