Assisted breeding technology in the saltwater crocodile Crocodylus porosus: a review and look to the future
Stephen D. Johnston
A H , John Lever B , Robby McLeod B , Edward Qualischefski A C , Monica Madrigal-Valverde D E and Brett Nixon F G
+ Author Affiliations
- Author Affiliations
A School of Agriculture and Food Sciences, The University of Queensland, Gatton, Qld 4343, Australia.
B Koorana Crocodile Farm, Coowonga, Qld 4072, Australia.
C Ecosystem Health Unit, Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, 1920 Coffey Road, Columbus, OH 43210, USA.
D Costa Rica Institute of Technology, School of Agronomy, San Carlos Campus, 223-21001, Alajuela, Costa Rica.
E Animal Science Department, University of Costa Rica, Campus Rodrigo Facio, 1501-2060, San José, Costa Rica.
F Priority Research Centre for Reproductive Science, School of Environmental and Life Sciences, Discipline of Biological Sciences, University of Newcastle, Callaghan, NSW 2308, Australia.
G Hunter Medical Research Institute, Pregnancy and Reproduction Program, New Lambton Heights, NSW 2305, Australia.
H Corresponding author. Email: s.johnston1@uq.edu.au
Reproduction, Fertility and Development 33(9) 503-518 https://doi.org/10.1071/RD20217
Submitted: 20 August 2020 Accepted: 1 November 2020 Published: 15 February 2021
Abstract
This review reports the current status of artificial breeding technology in the Crocodylia and the future requirements for the establishment of AI in the saltwater crocodile. Although there are challenges regarding safe restraint and immobilisation, semen collection of the saltwater crocodile by manual stimulation has proven effective in yielding sufficient volume and sperm concentrations for empirical and molecular analyses of sperm preservation and physiology. Nevertheless, there is still much to learn with respect to fundamental anatomy, physiology and behaviour in both sexes, but particularly in the female. Although lessons can be learned from successful AI in the alligator, the details of this research are not readily accessible. Future research needs to focus on the proximate factors of seasonality and the underlying control of the female’s annual reproductive cycle; this will require novel and innovative ways to collect blood samples without causing stress or injury, and ideally a dedicated crocodile research breeding colony. Because the saltwater crocodile is a farmed species, there is likely to be sufficient impetus for the application of assisted breeding technology to drive future productivity in the industry. These developments will also have benefits for the genetic and reproductive management of endangered captive populations.
Keywords: artificial insemination, crocodile farming, crocodilian conservation, cryopreservation, reproductive anatomy, reproductive models, reproductive physiology, reptile, semen collection, semen preservation.
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