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State of the industry in salmonid sperm cryopreservation Soledad Francke, IMV Technologies
During the last decade, genetic programs in aquaculture farming have experienced exponential development. Sperm cryopreservation represents a critical backup to accompany those advances, with the imperious need to move toward real automation of the process. The use of frozen semen allows to have genetic material for desired crosses, reduce seasonal effects, optimize the use of genetically valuable males and thus, substantially accelerate the genetic improvement of the farm. This process is used routinely in the main salmonid genetic companies and increasingly in other species, such as cleaner fish or lumpfish and marine species. In some cases, the level of frozen semen usage reaches more than 75% of the production of milt within some companies. However, there are still some important steps to take before cryopreservation becomes routine in production.
Cryopreservation challenges Achieving an acceptable fertility level with frozen semen has room for improvement, especially considering cryopreservation results can have variability within sub-species and even within males. Some publications suggest variations in cryopreservation results between different males in Atlantic salmon, based on seminal fluid composition. For other aquaculture species like sea urchins, researchers work with freezing curves and different cryoprotectant combinations for each type of sea urchin. The difference has been studied and works in landbased animals such as horses. Specialized stud farms with high-value stallions may use different freezing curves for each stallion. Achieving excellence requires research and testing for fine-tuning and optimization of freezing curves and techniques.
Figure 1. ISEVO Alpha. Straw filler with fluorescence detection.
It is also suggested that tolerance to freezing may be a hereditary condition within some lines. Therefore, in preparation for mass cryopreservation, it will be necessary to include the selection of those
Hatchery Feed & Management Vol 9 Issue 4 2021
