Characterization of female and male reproductive physiology
Basic information on a species reproductive physiology is often incomplete or absent for many zoological species.
Successful development of AI and its application to population management requires extensive research into the basic reproductive physiology, anatomy and behavior of the species.
Information from our center's research into basic reproductive physiology is used to form a species-specific reproductive baseline database, which can be incorporated into health assessments and conservation strategies for captive or free-ranging animals.
In collaboration with national and international zoological institutions, our center is developing AI procedures to facilitate reproductive and genetic management of ex situ populations of marine and terrestrial species.
Our center has developed AI using fresh and frozen-thawed sperm in five species of marine animals: killer whale, bottlenose dolphin, Pacific white-sided dolphin, beluga and the Magellanic penguin with over 60 offspring born to date. Research is currently underway to develop AI procedures in other marine animals including polar bears, emperor penguins and sharks.
Sex pre-selection using Sperm Sorting
Our center is the only organization in the world with a sperm sorting facility dedicated to the development of sex pre-selection technology in marine and terrestrial wildlife, to aid in their social, reproductive and genetic management.
Sex pre-selection, using sperm sorting and AI or IVF, is of particular significance to species which naturally exist in female-dominated social groups, such as the African and Asian elephant. A bias of the sex ratio towards females will greatly assist in maintaining socially cohesive groups and minimizing male-male aggression.
Sex pre-selection is also beneficial to the management of endangered species, as the preferential production of females can enable propagation of those species at a faster rate.
We collaborate with numerous zoological institutions to advance the development of sperm sorting procedures for marine and terrestrial species including dolphins, killer whales, elephants, rhinoceroses, deer, and gorillas.
Our research has led to the implementation of sperm sorting and AI as a successful captive management tool for the bottlenose dolphin, with 30 calves born to date using sex-sorted cryopreserved sperm, and a sex-predetermination success rate of 93%.
Sperm Collection and Preservation
Species-specific development of sperm collection and preservation methods, across marine and terrestrial wildlife, are another focus of our center.
Cryopreservation research is conducted with epididymal and ejaculated spermatozoa, toward the establishment of effective genome storage banks.
A suite of in vitro assessments are used to characterize ejaculate and sperm quality, and to optimize sperm collection and preservation protocols. Assessments using light microscopy, fluorescence microscopy and flow cytometric analysis include: computer assisted sperm analysis, DNA integrity, membrane fluidity, mitochondrial activity, morphology, plasma membrane integrity and acrosome integrity.
Our sperm cryopreservation research utilizes conventional freezing methods, as well as a novel directional freezing method (directional solidification), which enables fine control of sample cooling and freezing rates. In comparison with a conventional straw method, directional solidification has lead to improved in vitro sperm quality in a number of species examined by our group including the bottlenose dolphin, killer whale and rhinoceros. We also use directional solidification for the preservation of sex-sorted sperm undergoing a second freezing step. The strategy of freeze-thawing, sex-sorting then re-freezing has been optimized in the bottlenose dolphin, and one calf has been born after AI to date.
Our center and collaborators have transported cryopreserved semen around the world to facilitate the cooperative management of numerous ex situ species including killer whales, bottlenose dolphins, Pacific white-sided dolphins and belugas.