Effects of freezing storage on the stability of maternal cellular and humoral immune components in porcine colostrum.

The placental structure of sows is epitheliochorial and prevents maternal serum immunoglobulin transfer to the fetus; therefore, the piglet relies on the ingestion of colostrum to acquire passive immunity. Colostral antibody-mediated and cell-mediated immunity contribute to immunity in piglets. However, little is known about the effects of freezing at -20 °C on colostral immune components during short-term storage, whether this will somehow compromise the acquisition of passive immunity of newborn piglets fed with this colostrum and the humoral immunity in porcine colostrum, and to possible shifts in immunological levels in colostrum collections during the colostral period. Based on the average concentration of immunoglobulin, frozen and fresh colostrum did not differ significantly. Overall, there were no storage differences in total macrophages, granulocytes, and NK cells. However, the frozen colostrum presented T lymphocyte subsets and B lymphocytes significantly lower than the fresh colostrum (p ≤ 0.05). Therefore, to sustain higher piglet survival rates, B cells may be a selective strategy to ensure immune defense to neonatal piglets. According to our findings, colostrum can be stored by freezing at -20 °C for up to 30 days and surplus porcine colostrum can be collected from the sow up to eight hours after the start of farrowing.