Technical note: tissue residues of mimosine and 2,3-dihydroxypyridine after intravenous infusion in goats.

Abstract

Sixteen growing Alpine wethers (average BW 35 +/- 2 kg) were assigned to one of four treatments to evaluate tissue retention of the leucaena toxins mimosine (MIM) and 2,3-dihydroxypyridine (2,3-DHP). Treatments were infused i.v. for 2 d and were 1) saline control, 2) MIM (200 mg.kg BW-.75.d-1), 3) 2,3-DHP (200 mg.kg BW-.75.d-1), or 4) MIM (100 mg.kg BW-.75.d-1) + 2,3-DHP (100 mg.kg BW-.75.d-1). Immediately after the infusion, the goats were slaughtered and tissue concentrations of MIM and 2,3-DHP were determined via HPLC. No detectable levels of either toxin were found in spleen, heart, lung, or muscle; however, appreciable amounts of MIM and 2,3-DHP were found in plasma, kidney, and liver samples. Kidney MIM content was greater (P < .01) than that of liver, although liver tended to retain slightly more 2,3-DHP (P > .05). Infusion of MIM resulted in a plasma MIM content of 39 to 54 mumol/L and reduced (P < .01) plasma PHE and LEU. Infusion of 2,3-DHP resulted in a plasma 2,3-DHP content of 9.4 mumol/L and increased plasma THR, ARG, VAL, PHE, ILE, LEU, and LYS concentrations (P < .10). Humans consuming offals from ruminants consuming large amounts of the leguminous forage leucaena may be exposed to appreciable quantities of MIM and 2,3-DHP.