ZINC, THYMIC ENDOCRINE ACTIVITY AND MITOGEN RESPONSIVENESS (PHA) IN PIGLETS EXPOSED TO MATERNAL AFLATOXICOSIS B-1 AND G(1)

Growth retardation, thymic involution and impaired peripheral immune e fficiency are constant events in piglets exposed to maternal aflatoxic osis. Zinc may play a key role because of its requirement for good imm une responses, including thymic endocrine activity. Zinc is required t o activate a thymic hormone, i.e. thymulin (ZnFTS), which is responsib le for cell-mediated immunity. Zinc deficiency and decreased thymic en docrine activity are present in piglets fed from sows exposed to aflat oxins (AF) B-1 and G(1) as compared with healthy control piglets. In p articular, active ZnFTS is decreased while concentrations of inactive thymulin (FTS) are high. The in vitro addition of zinc up to the plasm a samples induces a reduction of inactive thymulin. The lymphocytes mi togen responsiveness (PHA) is decreased and a thymic cortical lymphocy te depletion is also present. These data suggest that the thymic defec t, followed by impaired peripheral immune efficiency, may largely depe nd by the low peripheral zinc bioavailability to saturate all thymulin molecules produced. (C) 1998 Elsevier Science B.V.