Amy R. Obringer1, Justine K. O’Brien, Robin L. Saunders2, Kazutoshi Yamamoto, Sakaé Kikuyama, Terri L. Roth
1Center for Research of Endangered Wildlife, Cincinnati Zoo & Botanical Garden, OH 45220, USA.
2CSIRO,
Tóm tắt
Spermiation and LH release in response to several methods of LHRH
administration were assessed in the American toad
(Bufo americanus), and the most successful method was
tested in the endangered Wyoming toad (Bufo baxteri).
Specific objectives were to: (1) compare spermiation
responses and plasma LH concentration after invasive and non-invasive LHRH
treatments; (2) evaluate sperm production in response to
different LHRH dosages; (3) characterize the timing of
sperm release post LHRH treatment; and (4) assess sperm
quality (motility, viability, morphology and acrosomal status). Male American
toads were administered 4 g LHRH by one of four routes:
(1) intraperitoneal injection (IP);
(2) subcutaneous injection (SQ);
(3) dorsal dermis absorption (DDA); and
(4) ventral dermis absorption (VDA). Aspermic urine only
was collected from saline-treated controls and DDA animals. Several VDA
animals released spermic urine; however, all LHRH-injected toads released
spermatozoa. IP animals produced higher sperm and LH concentrations than SQ
animals. The spermiation response in animals treated IP with 1 g LHRH was
similar to that in animals treated with 4 g, but lower LHRH dosages tested
produced inferior responses. Sperm production in responsive animals increased
over time during the 12-h sampling interval. Regardless of treatment, most
American toad spermatozoa were motile, viable, and acrosome-intact. Endangered
Wyoming toads were treated IP with 4 g LHRH, and spermic urine was collected.
Although most spermatozoa were viable and acrosome-intact, a considerable
percentage possessed structurally abnormal heads. A single IP injection of
LHRH appears to be a reliable and safe method for controlling spermiation in
toads and may be useful for assisting endangered amphibian propagation.
