Influence of mineral supplementation on 2,3-dihydroxypyridine toxicity in Angora goats

To study the effect of mineral supplementation on 2,3-DHP toxicity, 16 mature Angora wethers were randomly allocated to four treatment groups (M, DM, D and C). Two hours after the morning feeding; group M received a mineral mixture of 2 g of Fe2(SO4)3 • 7H20, 2 g of MgSO4 •7H20 and 2 g of ZnSO4 • 7H20 intraruminally in 80 mL of water; group DM received a similar mineral mixture plus 6 g of 2,3-DHP (DHP chelated with metal ions), group D received 6 g of 2,3-DHP in 80 mL of water and group C received 80 mL of water. In group D, two animals died within 24 h of receiving DHP and the other two animals were sacrificed to prevent suffering. Ruminal concentration of DHP was approximately 18 times higher in group D than in group DM (2.8 vs 0.16 mmol L-1; P<0.05) 4 h following treatment. Plasma DHP concentration, 6 h post treatment, was lower in group DM than in group D ( 15.2 vs 85.9 nmol mL-1, P<0.05). Urinary excretion of 2,3-DHP was much faster in group DM than in group D (P<0.05). Plasma triiodothyronine in group D was lower (110 vs 211 ng dL-1; P<0.05) than in group DM. It appears that mineral supplementation prevented 2,3-DHP toxicity. Faster urinary excretion of chelated 2,3-DHP suggests that 2,3-DHP must be chelated to be efficiently transported and cleared by the kidney.