Expanding cryopreservation to improve genetics in aquatic species

Rick Bogren

For more than 70 years, germplasm repositories based on cryopreservation — frozen sperm — have been widely used in improving animal genetics, particularly in cattle. Frozen sperm moved from research to commercialization and industrial development with cattle beginning in 1947. The use of cryopreservation in aquaculture, although starting at the same time, “has been trapped in research mode,” said LSU AgCenter researcher Terry Tiersch.

In the past 20 years, however, aquaculture has been catching up. Scientists have mapped the genomes of several fishes, including tilapia, trout and catfish, and are improving the production of hybrid catfish.

Recently, Tiersch has expanded from concentrating on farmed fishes to large-scale cryopreservation of a broader variety of aquatic species, including those found in the wild and in zoos and aquariums. More importantly, he is developing approaches for protecting genetic resources for fish used in biomedical research.

Tiersch and colleagues have established the Aquatic Germplasm and Genetic Resources Center in the former AgCenter Dairy Improvement Center building near the LSU Baton Rouge campus. They are outfitting the 23,000-square-foot facility to have commercial-scale capabilities. The center can process and freeze a half million samples per week — more than all of the other aquatic researchers in the world combined could produce in years of work.

With current grant funding of $2 million from the National Institutes of Health and more than $150,000 from the U.S. Department of Agriculture and other groups, Tiersch’s group has pioneered high-throughput processing of genetic resources for improving disease resistance and fast growth in a variety of aquatic animals while also addressing environmental concerns.

“We want to preserve and distribute genetics of value by supporting development of repositories for genetic resources,” Tiersch said. “No one else was prepared to do this at a commercial-scale before we started this center.”

The cryogenic technology Tiersch’s group has created can be used to create repositories for saving genetic resources. Zebrafish are the largest aquatic model for studying diseases. They have the same basic genetics as humans, and they’re small and can be easily maintained.

“Researchers can keep thousands of zebrafish in a few tanks when other animals like rats or monkeys would need significantly larger space and cost much more,” Tiersch said.

Tiersch’s group is collaborating with several engineering disciplines to develop technologies for collecting and maintaining germplasm. This includes core technologies in 3-D printing, microfluidics, and electrical and computer engineering.

In addition to zebrafish, the AgCenter facility is developing resources to collect and maintain genetic information from improved farmed strains and endangered species. Current efforts include work with live-bearing fish, oysters, and marine species such as coral and sea slugs, which have a nervous system used to mimic human neurons.

Samples and genetic information from the AgCenter facility go to the USDA National Animal Germplasm Program. Similar to the USDA plant preservation program, the animal program has specific committees for each species. Tiersch is chairman of the Aquatic Species Committee, which includes representatives from universities, industry and government.

“This is the leading repository for preserving our nation’s animal genetic resources,” he said.

Rick Bogren is associate editor of Louisiana Agriculture and a professor in AgCenter Communications.

(This article appears in the fall 2018 issue of Louisiana Agriculture.)

Read "Development of Sperm Banks to Save Endangered Fishes" by Yue Liu and Terrence R. Tiersch, which is also in the fall issue.

Watch the video news story about the cryopreservation of aquatic germplasm.

Terry Tiersch.jpg thumbnail

Terry Tiersch, aquatic researcher at the LSU AgCenter Aquatic Germplasm and Genetic Resources Center in Baton Rouge, displays the “Cajun Ejector” that was made on a 3D printer and is used to increase the efficiency of freezing and storing straws of genetic material in containers of nitrogen. Photo by Johnny Morgan

12/14/2018 8:18:47 PM
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