Effects of mimosine on plasma amino acid concentrations in Angora goats.

摘要

Effects of mimosine intravenously infused for 2 days or orally dosed on plasma amino acid concentrations in Angora goats were determined. 20 mature Angora wethers (36±1.9 kg body weight (BW)) were infused for 2 days with mimosine 79, 102 and 135 mg/kg BW daily, 2,3-dihydroxypyridine (2,3-DHP) 90 mg/kg BW daily or saline; plasma was sampled before infusion and 24 and 48 h later. Seven days after infusion began, fleece shedding was observed in all goats receiving mimosine, but not in any goats infused with 2,3-DHP or saline. Mimosine decreased (P<0.05) plasma concentrations of glycine, threonine, arginine and lysine. Amino acid concentrations in goats infused with 2,3-DHP were similar to levels in control goats. In another experiment, Angora bucklings (23±0.5 kg BW) were orally dosed with mimosine 400 or 600 mg/kg BW; plasma samples were collected before dosing and 22 and 46 h later. At 9 days after oral doses of mimosine, no fleece shedding was noticeable; however, at 31 days changes in fleece status of some goats were observed. For threonine and arginine, mimosine dosing decreased plasma concentrations at 22 h compared with concentrations before dosing (P<=0.05), and for threonine, arginine and lysine mimosine dosing increased amino acid concentrations at 46 h (P<=0.05). The increase in valine concentration due to mimosine dosing was greater than 0 for mimosine 400 mg/kg BW (P<0.05) and at 46 h (P<0.01), and was greater (P<0.05) at 46 than 22 h. The increase in leucine concentration due to mimosine dosing differed from 0 for mimosine 400 (P<0.05) and 600 mg/kg BW (P<0.05) and at 46 h (P<0.01), and was greater (P<0.05) at 46 vs. 22 h. It is concluded that, 2-day infusion of mimosine to defleece altered plasma concentrations of some amino acids.