Abstract
Background: It is well known that many anurans do not reproduce easily in captivity. Some methods are based on
administration of mammalian hormones such as human chorionic gonadotropin, which are not effective in many
frogs. There is a need for simple, cost-effective alternative techniques to induce spawning.
Methods: Our new method is based on the injection of a combination of a gonadotropin-releasing hormone (GnRH)
agonist and a dopamine antagonist. We have named this formulation AMPHIPLEX, which is derived from the
combination of the words amphibian and amplexus. This name refers to the specific reproductive behavior of frogs
when the male mounts and clasps the female to induce ovulation and to fertilize the eggs as they are laid.
Results: We describe the use of the method and demonstrate its applicability for captive breeding in 3 different anuran
families. We tested several combinations of GnRH agonists with dopamine antagonists using Lithobates pipiens. The
combination of des-Gly10, D-Ala6, Pro-LHRH (0.4 microrams/g body weight) and metoclopramide (10 micrograms/g
BWt. MET) was most effective. It was used in-season, after short-term captivity and in frogs artificially hibernated under
laboratory conditions. The AMPHIPLEX method was also effective in 3 Argentinian frogs, Ceratophrys ornata,
Ceratophrys cranwelli and Odontophrynus americanus.
Conclusion: Our approach offers some advantages over other hormonally-based techniques. Both sexes are injected
only once and at the same time, reducing handling stress. AMPHIPLEX is a new reproductive management tool for
captive breeding in Anura.
number of eggs per. toad, and 2) a greater survival of fertilized
eggs to swim-up stage. The number of eggs from
females receiving two primings was similar to the number
of eggs from B. baxteri in nature indicating that egg production
is not dependent on hibernation. However, considering
the low fertilization rates in our study, we cannot
make a similar statement for egg quality. It may be that hibernation plays an important role in the B. baxteri for
final oocyte development and our current protocols
rushed the recruitment of a large cohort of eggs. Therefore,
the development of methods to increase fertilization and
embryo survival rates by producing a greater number of
mature follicles before ovulation should be prioritized in
the development of reproduction technologies for B. baxteri