Category — CREW
Glass Glass Baby: Birth of Healthy Kittens following Sperm Vitrification for Artificial Insemination
A world leader in small cat reproductive research, our Center for Conservation and Research of Endangered Wildlife (CREW) has successfully produced the first non-human offspring – two kittens – using vitrified sperm (semen preserved as glass instead of ice) for artificial insemination (AI). Dr. Bill Swanson explains the significance of this breakthrough in this video.
Cryopreservation of cat semen for assisted reproduction can be challenging, requiring technical expertise and specialized equipment for semen collection, processing and freezing. As a simplified alternative to standard semen cryopreservation methods, CREW scientists have been investigating the use of vitrification – the ultra-rapid cooling of liquids to form a solid without ice crystal formation. This approach essentially preserves semen as glass instead of ice.
For vitrification, cat semen is diluted in a chemically-defined medium containing soy lecithin and sucrose as cryoprotectants and, after a five minute equilibration period, pipetted in small volumes (~30 microliters) directly into liquid nitrogen to form tiny glass marbles of frozen sperm.
In initial studies, we found that cat sperm survived vitrification as successfully as that frozen using standard straw freezing methods and that vitrified sperm were capable of fertilizing cat oocytes in vitro. In our first assessment of in vivo viability, eight of these embryos were transferred into three synchronized females. Although one female appeared to have two early implantations, no offspring were produced.
In a follow-up study, artificial insemination (AI) with vitrified sperm was assessed in three additional females. With our laparoscopic oviductal AI technique (LO-AI), only a couple million sperm are required per insemination, allowing the use of the relatively low sperm numbers that are preserved in vitrified semen pellets. Following LO-AI with vitrified sperm, all three females conceived, with two of the pregnancies progressing to term and culminating in the birth of two healthy kittens in early April. These kittens, a male named Vito (short for vitrification) and a female named Elsa (after the character in the movie Frozen), are the first non-human offspring – of any species – produced with vitrified sperm (although three human babies have been born from earlier research).
Our preliminary results with semen from fishing cats and ocelots indicate that vitrification is effective for preserving post-thaw sperm viability and function across cat species. These findings suggest that this fast and simple cryopreservation method may have broad applicability for semen banking of endangered felids housed in zoos and possibly living in the wild.
The study’s lead author, veterinary student Jaci Johnson, has been selected to present these findings at the upcoming American Association of Zoo Veterinarian’s Annual Meeting in Portland, Oregon. (Funded, in part, by the Procter & Gamble Wildlife Conservation Scholarship program in collaboration with Ohio State University’s College of Veterinary Medicine.)
- Reprinted from the Spring 2015 CREW Progress Report
May 14, 2015 No Comments
Guest blogger: Zoo Academy student, Jane Collins
The Cincinnati Zoo & Botanical Garden’s Center for Conservation and Research of Endangered Wildlife (CREW) is famously known to the world for its hard work on saving endangered plants and animals. Whenever people learn about CREW, they hear about the projects on polar bears, Sumatran rhinos, wild cats, and many plant species including autumn buttercup, four-petal pawpaw, and Avon Park harebells. You learn a lot about how important these projects are, but I believe there is one important aspect of CREW that is not as well known to Zoo visitors as it should be. I’ll give you a hint, re-read the title!
That’s right. I’m talking about cats. I don’t mean the wild African lion, cheetah, or tiger that you may have been thinking about. I mean domestic cats. CREW’s Domestic Cat Research is actually important to saving endangered big cats in the wild. These special cats help CREW with a number of things, including testing a contraceptive vaccine and conducting oviductal artificial inseminations and embryo transfers.
The cats in this program are given vaccines for common diseases and are spayed and neutered when at the appropriate age so they are completely cared for. CREW volunteers take the time to socialize with the cats also so they are very affectionate cats and are never neglected.
As a Zoo Academy student, I personally have had the opportunity to spend time with the cats and see up close how well they are treated. Washing cat dishes, litter pans, animal carriers, and a few other responsibilities may have not been the finest experience, but I liked that I was making even the smallest contribution to the care of the cats. I also was able to spend quality time with most of the cats playing and relaxing, whichever the cats preferred for the day. I had a great time learning a few of the cats’ individual personalities. One cat physically demands love and affection by climbing right into your lap. Another is very vocal. And another cat even loves water.
My favorite cat was a three-year old grey tabby with black stripes. He was the largest male domestic cat I have ever seen and looked like he belonged deep in a dark jungle rather than at a zoo. At end of my time at CREW, he was up for adoption. I couldn’t bring myself to part with him and decided to take him home. His new name is officially Chaz. He likes to follow me around EVERY square inch of my house and cries when I’ve gone too long without petting him. He is a loving member of my family. It is very cool to have a cat from the Cincinnati Zoo that has contributed to research that helps to save endangered wild cats.
April 8, 2015 1 Comment
The loss of our female Sumatran rhino “Suci” to iron storage disease just over a year ago on March 30, 2014 was a devastating blow to the Cincinnati Zoo’s Sumatran rhino breeding program. Iron storage disease is an insidious disease affecting many wildlife species that are maintained in zoos, ranging from marine mammals to birds. In addition to Sumatran rhinos, black rhinos are susceptible to the disease, whereas white rhinos and Indian rhinos remain largely unaffected.
The disease is extremely challenging because we do not know how to prevent it, diagnose it or treat it. The only known cure for the disease is frequent, large volume phlebotomies (blood collection), but nobody knows how much blood to draw or how often it must be removed to keep a rhino healthy, and it is difficult to perform phlebotomies without anesthesia. The best method for monitoring iron storage disease is to measure serum concentrations of ferritin, a protein involved in iron transport and storage, but ferritin can be species-specific, so an assay for humans or horses may not work accurately in rhinos. Such was the case with our Sumatran rhinos.
However, thanks to a dear family committed to helping rhinos that wanted to make a gift in honor of Suci, CREW has embarked on a new study to develop an assay specific for measuring rhino ferritin. The first step – isolating the rhino ferritin protein – is complete, and our goal is to have a functional assay by this coming summer. Our hope is that the assay will be used to monitor iron storage status in many rhinos throughout North American zoos to ensure the disease is detected before the rhino becomes sick.
This project was made possible by the generous donation of Mr. and Mrs. Jeremy S. Hilton and Family.
(Reprinted from CREW Review Fall 2014)
April 3, 2015 4 Comments