Fresh storage of rainbow trout (Oncorhynchus mykiss) semen using a non-aqueous medium

Several media for the storage of fresh semen from rainbow trout at 4 degrees C were evaluated. Semen was diluted with an equal volume of fluorocarbon, a 1:1 fluorocarbon:extender emulsion, a 2:1 fluorocarbon:extender emulsion, or with extender, or was stored undiluted. The semen was stored under moisture-saturated or non-saturated air. Efficacy of treatment was evaluated using motility rating, percentage of dead spermatozoa as determined by fluorometry, leakage of lactate dehydrogenase (LDH) activity into seminal plasma, and fertility trials during the storage period. Unlike motility ratings and fluorometry, measurement of LDH leakage to estimate sperm viability during storage with fluorocarbon did not give clear results due to the separation of the non-aqueous fluorocarbon from the aqueous seminal plasma phase. Semen diluted 1:1 with fluorocarbon maintained sperm viability at an acceptable level for 37 days. Duration of sperm viability was significantly longer under moisture-saturated air than under non-saturated air..