Relationships between passive absorption of immunoglobulin G by the piglet and plasma concentrations of immunoglobulin G at weaning

To examine the relationships between passive acquisition of immunoglobulin G (IgG) by piglets from colostrum and concentrations of plasma IgG at weaning, IgG concentrations in the blood plasma of piglets naturally suckling the sow were measured in the first week of life and at 28 days of age in three experiments. In two experiments the quantities of specific antibodies (anti-Newcastle disease virus, NDV) transferred from the sow to the piglet in colostrum were also quantified. The concentrations of IgG in piglet plasma at 28 days of age were significantly and positively related to concentrations in plasma at 2 and 7 days of age. NDV-IgG in piglet plasma declined more rapidly than total IgG between 7 and 28 days of age, but not between 2 and 7 days of age. In one experiment, concentrations of IgG in piglet plasma at 28 and 35 days of age were related to the diet the sow received during pregnancy, with diets including marine oil giving higher values. Estimates were made of the total amount (rather than concentration) of IgG in piglet plasma at different ages and these showed that amounts of IgG increased between 7 and 28 days of age, but not between 2 and 7 days; a similar conclusion was made from the dilution of NDV IgG in piglet plasma. Therefore, these estimates suggested that naturally suckling piglets begin synthesising IgG from 7 days of age and that the amounts of IgG synthesised are positively correlated with the amounts of IgG absorbed from colostrum. (C) 2003 Elsevier Science B.V. All rights reserved.