title: Effects of mimosine and 2,3-dihydroxypyridine on fiber shedding in Angora goats.
abstract: The effects of intravenous infusion of mimosine or 2,3-dihydroxypyridine (2,3-DHP) and the effects of oral dose level of mimosine on fiber shedding in Angora goats were determined. In one experiment, 20 mature Angora wethers (36+/-1.9 kg BW) were infused for 2 d with 79, 102, or 135 mg/(kg BW.d) of mimosine, 90 mg/(kg BW.d) of 2,3-DHP, or saline. At 7 d after infusion began, fiber shedding was observed in all goats receiving mimosine but not in any goats infused with 2,3-DHP or saline. Fiber shedding varied among goats; in some goats, fiber shedding was complete and occurred without hand-plucking, whereas in others fiber was retained by nonshed fibers but could be removed by hand-plucking. Nonshed fibers were larger in diameter and more likely to be medullated (P < .05) compared with hand-plucked fibers. Mean plasma mimosine concentration at 24 and 48 h after infusion began was 79 and 98 micromol/L (P < .05), respectively, and greater (P < .05) for mimosine infused at 135 than at 102 mg/(kg BW.d) (89, 68, and 108 micromol/L for mimosine infused at 79, 102, and 135 mg/[kg BW.d], respectively; SE 9.5). In another experiment, oral dosing of eight Angora bucks (23+/-.5 kg BW) with 400 or 600 mg/kg BW of mimosine rapidly increased plasma mimosine concentration, which reached approximately 100 and 160 micromol/L at 5 h after dosing; however, periods of time during which plasma mimosine concentrations were comparable to those in the first experiment were considerably shorter. Oral mimosine dosing did not induce fiber shedding in 7 d. After 31 d, fiber was retained by nonshed fibers but could be removed by hand-plucking or could only be partially removed with difficulty by hand-plucking. There were no toxic effects of mimosine or 2,3-DHP administration; only minor, short-term inhibitions of feed intake by mimosine were noted in some goats. In conclusion, mimosine holds promise as a safe means to remove fiber of Angora goats; further research is necessary to characterize the seasonality of follicle activity and to develop convenient means of mimosine delivery.
authors.affiliation: E (Kika) de la Garza Institute for Goat Research, Langston University, OK 73050, USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: Reis
authors.forename: R
authors.initials: R
authors.lastname: Puchala
authors.forename: T
authors.initials: T
authors.lastname: Sahlu
authors.forename: A L
authors.initials: AL
authors.lastname: Goetsch
mesh_terms: D000284:Administration, Oral; D000818:Animals; D006041:Goats / Q000502:physiology*; D006197:Hair / Q000187:drug effects*; D007262:Infusions, Intravenous / Q000662:veterinary; D008898:Mimosine / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D011725:Pyridines / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*
chemical_list: D011725:Pyridines; D008898:Mimosine; C035877:2,3-dihydroxypyridine