Zinc, thymic endocrine activity and mitogen responsiveness (PHA) in piglets exposed to maternal aflatoxicosis B1 and G1

Growth retardation, thymic involution and impaired peripheral immune efficiency are constantevents in piglets exposed to maternal aflatoxicosis. Zinc may play a key role because of itsrequirement for good immune responses, including thymic endocrine activity. Zinc is required to.activate a thymic hormone, i.e. thymulin ZnFTS , which is responsible for cell-mediatedimmunity. Zinc deficiency and decreased thymic endocrine activity are present in piglets fed from.sows exposed to aflatoxins AF B and G as compared with healthy control piglets. In particular,11.active ZnFTS is decreased while concentrations of inactive thymulin FTS are high. The in vitroaddition of zinc up to the plasma samples induces a reduction of inactive thymulin. The.lymphocytes mitogen responsiveness PHA is decreased and a thymic cortical lymphocytedepletion is also present. These data suggest that the thymic defect, followed by impairedperipheral immune efficiency, may largely depend by the low peripheral zinc bioavailability tosaturate all thymulin molecules produced.