Humoral Immune Response of Immunized Sows with Recombinant Proteins of Enterotoxigenic Escherichia coli

Enteric disorders in pigs are related to the fimbriae F4 (K88), F5 (K99), F6 (987P), F41 and F18 of enterotoxigenic Escherichia coli (ETEC). Immunization of sows with adhesins is important to stimulate the production of antibodies and the consequent transfer of these to the piglets via colostrum to prevent diarrhea during the neonate period and after weaning. The objective of this study was to evaluate the immune response of the sows immunized with recombinant ETEC proteins (F4, F5, F6, F18 and F41). The immune response of the sows immunized with the recombinant proteins was compared with a commercial vaccine containing ETEC bacterins. The study was performed on a commercial farm and included nine pregnant sows divided into three groups: G1 was vaccinated with recombinant proteins (n = 3); G2 was vaccinated with the commercial vaccine (n = 3); and G3 was vaccinated with sterile buffered saline (PBS) (n = 3). All the sows were fed a balanced diet without antibiotics and water ad libitum. The recombinant fimbriae stimulated the specific humoral immune response of the immunized sows. There was a statistically significant increase in the levels of antibodies to the fimbriae F4 (K88), F5 (K99), F6 (987P) and F18 in the sows vaccinated with the recombinant proteins compared with the control group. The colostrum IgG titers for all fimbriae in all the immunized sows were significantly increased compared to the control group. Additionally, all the piglets exhibited significantly increased antibody levels relative to all fimbriae when compared with those in the unimmunized control group, demonstrating successful antibody transfer via colostrum of the sows to the piglets.