Tissue residues of mimosine and 2,3-dihydroxypyridine after intravenous infusion in goats

T. Sahlu, R. Puchala, P. J. Reis, J. J. Davis, K. Tesfai, J. M. Fernandez, and A. A. Millamena

Sixteen growing Alpine wethers (average BW ± 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), 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 < 0.01) than that of liver, although liver tended to retain slightly more 2,3-DHP (P > 0.05). Infusion of MIM resulted in a plasma MIM content of 30 to 54 mol/L and reduced (P < 0.01) plasma PHE and LEU. Infusion of 2,3-DHP resulted in a plasma 2,3-DHP content of 9.4 mol/L and increased plasma THR, ARG, VAL, PHE, ILE, LEU, and LYS concentrations (P < 0.10). 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.