ARS | Publication request: Tetraploid production in salmonids

Submitted to: Aquaculture America Conference
Publication Type: Abstract Only
Publication Acceptance Date: February 1, 2011
Publication Date: February 28, 2011
Citation: Weber, G.M., Hostuttler, M.A., Wiens, G.D., Beers, B., Leeds, T.D. 2011. Tetraploid production in salmonids. Aquaculture America Conference. 392.

Technical Abstract: Tetraploid induction is of interest to aquaculture and fisheries as part of a more efficient means of producing triploid fish by mating a tetraploid parent with a diploid parent (tetraploid-derived triploids). Tetraploid induction has previously been reported in salmonids including rainbow trout and coho salmon. At the USDA/ARS National Center for Cool and Cold Water Aquaculture, we have been working on tetraploid induction in Atlantic salmon, brook trout, and brown trout, and improving efficiency of tetraploid induction of rainbow trout. We have successfully induced tetraploidy in all four species by exposing embryos to 9000 psi for 8 minutes starting at 62-65% of the first cleavage interval (FCI). We have thus far produced 3 generations of tetraploid rainbow trout and reared 300 tetraploid Atlantic salmon to the fingerling stage. In collaboration with Paint Bank Fish Culture Station, Virginia DGIF, we have reared a single tetraploid brook trout to the fingerling stage, and confirmed tetraploid induction in brown trout embryos. A major impediment to consistent induction of tetraploidy is variation in the FCI. We have observed year to year variation in FCI at 10 degrees C within the same genetic population suggesting an environmental component to this variation. The value of tetraploid-derived triploids to the aquaculture industry is dependent on their performance. Studies evaluating the performance of tetraploid-derived triploids are limited and often confounded by differences in the genetic backgrounds of ploidy forms being compared. Performance of rainbow trout is being compared among diploids, pressure-induced triploids, and tetraploid-derived triploids which are derived from mating a tetraploid male with a diploid female. Ten families were generated for each ploidy form, with the diploid and pressure-induced triploid families being full-sibs and the tetraploid-derived triploid families being maternal half-sibs to the two other forms and sharing a full-sib sire. Experiments are currently underway to compare the three ploidy forms for growth performance, resistance to Flavobacterium psychrophilum in a laboratory challenge, and plasma cortisol in response to a crowding stress. These comparative performance data will be presented and discussed.