Work in Slovenia and farewell to Nataša and Jovana

Between April 3rd-8th, we had our annual trip to Tolmin, Slovenia do conduct field work on grayling (Thymallus thymallus) sperm cryopreservation. As a reminder: the Angling Club of Tolmin uses cryopreserved sperm and molecular markers to increase the percentage of the autochthonous Adriatic genotype of the grayling in its waters. Sperm is taken and frozen from wild individuals during the spawning season while fin clips of the same fish are sent to Ljubljana for genetic analysis. Once the results of the genetic analysis arrive (2-3 weeks) people of the Angling Club can use the sperm of those individuals that have the highest percentage of the Adriatic genotype. Unfortunately, this year only one male individual was caught...
Also, we carried out isolation and cryopreservation of marble trout (Salmo marmoratus) and grayling testes and ovaries. The objective of these studies is to use these gonads later for isolation of spermatogonia and oogonia. These can then be transplanted into suitable recipients, in this case triploid rainbow trout larvae. At the moment we are waiting for a shipment of mixed-sex triploid rainbow trout embryos, thus, the gonads will have to stay frozen until these arrive.
Finally, after a one-month stay, we had to say goodbye to our two students from the University of Novi Sad, Nataša Cvetković and Jovana Lovren. They endured an incredibly tough one month of intensive training in cryopreservation, transplantation, histology and immuno-histochemistry in our lab and did a very good job. Thank you, Nataša and Jovana, and hope to see you soon in Hungary for new adventures!
We would also like to express our gratitude to Mr. Dušan Jesenšek, manager of aquaculture activities of the Angling Club of Tolmin for his help and guidance, as well as to Dr. Simona Sušnik-Bajec, Dr. Aleš Snoj and Ida Djurdjevič of the University of Ljubljana for their participation in the experiments.

Dissection of grayling juveniles for the isolation of gonads

Fish collection

Sample collection for genetic analysis and cryopreservation

The first grayling male

Sperm stripping

Cryopreservation on the field

Parallel experiments