DNA fragmentation and membrane integrity in sperm of farmed Arctic charr (Salvelinus alpinus)

Abstract Despite the relatively long history of captive breeding, the Arctic charr still exhibits a generally low, but highly variable reproductive performance in aquaculture. A recent publication exposed potential paternal factors influencing the reproductive outcome of Arctic charr broodstock from the Swedish breeding program. Interestingly, the paternal factor appeared to be more closely connected to embryo survival than to fertilisation rates. This lead to speculations on whether e.g. chromatin related issues, potentially related to oxidative stress could be involved. In order to investigate this hypothesis the present study assessed the levels of DNA fragmentation, using the SCD-method, and membrane integrity, using flow cytometry, in sperm of farmed Arctic charr. Moreover, the existence of associations was tested between DNA fragmentation and membrane integrity in individual semen samples and viability of their resulting progeny. We found high levels of DNA fragmentation in sperm from the Arctic charr sires, ranging from 24% to 86% with a median of 67%. Membrane integrity values were high, with individual levels of 93.1% to 99.6% viable sperm cells, median 98.8%. DNA fragmentation and membrane integrity values were moderately correlated (r = 0.304, p