EN
The absolute and relative levels of immunoglobulins (Ig) G, M, and A in porcine mammary secretions throughout lactation period were estimated. Concentrations of each immunoglobulin were determined by ELISA kits. The results of the study confirmed that pigs, like other mammals, have colostral and milk phases of lactation, distinguished by the concentrations of IgG and IgA. The amount of IgG showed a dramatic 27-fold decline from the beginning to day 6 of lactation. The IgM concentration decreased over threefold at the same time. Concentration of IgA at the day 6 of lactation was almost 4-fold lower than that at the beginning of lactation. The relative contribution of IgG and IgA to the total Ig content becomes reversed during lactation. Summarising, in pigs, transformation of colostrum to milk was characterised by dramatic decrease in total Ig content, connected with the change of predominant immunoglobulin. The predominant immunoglobulin in colostrum was IgG, which plays an important role in systemic immunity, while in milk a major Ig was IgA, responsible for the protection at mucosal surface level. As concentrations of Ig in colostrum are very variable, an improved understanding of factors influencing colostrum Ig concentration is now desirable.