FUMONISIN TOXICOSIS IN DOMESTIC-ANIMALS - A REVIEW

Fumonisins are the most recently discovered group of mycotoxins with i mportant implications in animal health. Equine leucoencephalomalacia a nd porcine pulmonary edema are diseases observed for many years, but t heir etiology was unknown. These 2 syndromes were recently reproduced experimentally after administration of purified fumonisin B1 (FB1). Th e main target organs for the toxic actions of FB1 are the brain in hor ses and the lungs in the case of swine. However, severe liver damage i n both species and pancreatic lesions in swine are also observed, espe cially when Fusarium moniliforme culture material (FCM) or naturally c ontaminated corn are used as the source of the fumonisins. Experimenta lly induced fumonisin toxicosis has been studied in poultry and cattle using FCM or naturally contaminated corn or corn screenings as the my cotoxin source. Results have shown a much lower sensitivity of these s pecies to the toxic action of fumonisins when compared to horses and p igs. However, adverse effects on performance parameters of broiler chi ckens and turkey poults and on selected immune parameters of chickens and cattle were reported. In order to confirm these observations, toxi cological studies using purified fumonisins are required. Studies to d etermine the interaction of fumonisin with other Fusarium toxins and o ther mycotoxins are also needed. No studies on the toxicokinetics of f umonisins have been reported. The toxicodynamics (mechanism of action) of fumonisins appears to be a blockage in the synthesis of sphingolip ids and thus constitute a unique toxicological action among the known mycotoxins. Fumonisins inhibit the enzymes sphinganine- and sphingosin e-N-acyltransferases causing an increase in the serum levels of free s phinganine and to a lesser extent of free sphingosine, which suggests that sphinganine N-acyltransferase is the preferred target for fumonis ins. Increased serum levels of free sphingoid bases and the serum free sphinganine:free sphingosine ratio, and decreased serum levels of com plex sphingolipids, have been observed in pigs, horses and chickens ex posed to fumonisins. These biochemical changes occur rapidly after exp osure to FB1 and have been suggested to be used as early diagnostic te sts for fumonisin toxicosis.