AIMAP Report for: Implementation of new cryopreservation technology

Cryopreservation of sperm is the cornerstone of the agricultural livestock breeding program facilitating the transfer of top-quality genetic broodstock internationally. In contrast, cryopreservation of sperm (milt) from finfishes is a relatively new technology in the aquaculture industry and current methodologies employed by the BC salmon farming industry result in fertilization success rates of approximately 25%. This is well below the fertilization success rates obtained by other countries, such as New Zealand whose refined cryopreservation techniques attain fertilization success rates of 75-80%, roughly comparable to fertilization rates obtained using fresh (non-cryopreserved) milt. To overcome this production defficiency the BC Salmon Farmer’s Association (BCSFA) proposed a technology transfer initiative and invited representatives from New Zealand King Salmon (NZKS) to travel to BC to provide first-hand instruction of their milt cryopreservation methodologies to members of the BCSFA. In October of 2008, two NZKS delegates, Michael Anderson and Karl French, traveled to Canada and partook in a multi-day demonstration and instructional tour of hatcheries in the Campbell River area on Vancouver Island including Creative Salmon, Mainstream Canada and Marine Harvest Canada. At each hatchery Mike and Karl worked with hatchery technicians and demonstrated the methods NZKS uses to obtain high levels of fertilization success with cryopreserved milt. In turn, the companies provided tours of their hatchery facilities for the NZKS representatives to compare to New Zealand’s current hatchery technology.

The overall objective of this project was to import international expertise and advanced training to members of the BCSFA so that cryopreservation techniques can be utilized commercially on a pilot scale in the BC Atlantic and Chinook salmon farming industry. The success of this primary objective affords the future enhancement of production efficiencies as follows:

1. All companies foresee increased productivity based on having more reliable results when using cryopreservation technology. A consistent increase in fertilization rates using cryopreserved milt would increase genetic diversity and potentially growth and survival by facilitating genetic transfer between year classes and screening genomic markers in selective breeding programs.
   
   
2. Creative Salmon reported a slight improvement using milt processed with the New Zealand King Salmon methodology compared to their own. The Marine Harvest Big Tree hatchery reported very low rates of survivorship both for eggs fertilized using the cryopreserved milt and unfrozen “normal” milt. However Marine Harvest has also recognized that trying to spawn Atlantics in late October was a risk (too early). The female brood were ready but there was difficulty getting good milt from the males and this will likely affect the results.
   
   
3. Implementation of alternative cryopreservation methodologies will hopefully yield more reliability in fertilization success and will allow more of the milt top be stored and used for future generations of broodstock.
   
   
4. In the long run companies increased fertilization rates using cryopreserved milt will lend to less wasted eggs (unfertilized) and make it easier to use cryopreserved milt to increase genetic diversity and do more selective breeding across brood years.
   
   
5. Efficiencies for mass sterilization were not a component of this project.
   
   
6. A dialogue has been opened between BC salmon farming hatcheries and New Zealand King Salmon for further exchange of methods and ideas.
   
   
7. Mainstream Canada had two technicians involved in the training, Creative Salmon had three and Marine Harvest had eight.
   
   
8. What are the overall results/ impressions of the pilot phase of the project?
   
   Mainstream: “It was good to see another method of cryopreservation of milt. The method presented however, was not very practical for our isolated facility and the technique as presented, did not use milt efficiently enough to make it practical.”
   
   Creative Salmon: “It was very good getting other ideas about cryo. Unfortunately, their method of freezing was very slow and would make it extremely difficult to get a large number samples frozen in a relatively short period of time. Their method of thawing was more of interest as we can hopefully incorporate some of their methodology in our current one and improve fertilization rates. If this did not help much, then we could look at their freezing methods and see if we could use some of these as well.”
   
   Marine Harvest: “In general it was a positive experience as it offered options in for breeding. If the success to eye up and hatch could be increased then there could be some use for cryogenics.”
   
   
9. What are the next steps using these techniques and how can these techniques be moved into full scale commercial utilization?
   
   Mainstream: “I will run trials implementing some of the procedures that I learned from this project in my regular cryopreservation procedures. I will also run more trials with different extenders and try to maximize the number of eggs that can be fertilized with a given amount of milt.”
   
   Creative Salmon: The next step would be to do some trials at next year’s spawns trying to incorporate some of their methodology in our current methods to see if this would increase fertilization rates.
   
   Marine Harvest: “There also was some question about the timing to thaw the milt. The method used the same time as used for Chinook milt. Maybe there is a difference in performance. There was a problem with the capillary tube exploding so we lost some samples. There were solutions to deal with that in the future.”

Overall all companies gained new insight into alternative cryopreservation techniques and will continue to experiment using the different methodologies that were demonstrated by the New Zealand King Salmon representatives. In addition, as stated in the proposal (page 4, paragraph 3), an intellectual property/confidentiality agreement was drawn up between the BCSFA and New Zealand King Salmon. The cryopreservation techniques are proprietary within the BC salmon farming industry unless express permission is given by New Zealand King salmon to share the information. The main goal of this agreement is to protect New Zealand King Salmon’s competitiveness within New Zealand and with Australian salmon producers and this condition for knowledge exchange is acceptable to the BC salmon farming industry.