Metformin improves fish sperm quality by regulating glucose uptake capacity during in vitro storage

Transferrin maintains the motility rate, ATP content, and DNA integrity of common carp spermatozoa during short-term storage

Short-term sperm storage is a straightforward and cost-effective method of managing logistics in large scale fish hatchery operations but may result in decline in sperm quality. For effective artificial reproduction of fish, use of an appropriate additive to optimize sperm storage conditions is essential. In this study, it was investigated the effect of purified seminal plasma transferrin (Tf) at 10 μg/ml on relevant parameters in common carp Cyprinus carpio sperm during short-term storage. We compared sperm motility and curvilinear velocity, adenosine triphosphate (ATP) content and DNA fragmentation of fresh spermatozoa to that stored for 24, 48, 72, and 144 h with or without Tf. The percentage of motile cells and the curvilinear velocity of spermatozoa in stored samples for 72 h with transferrin supplementation were greater compared to samples with no added protein. The ATP content in samples without added transferrin was reduced (P < 0.05) after 72 h of storage, in contrast to the levels observed in transferrin-supplemented sperm. A time-dependent increase in DNA fragmentation was observed. Significantly lower DNA damage, expressed as percent tail DNA (10.99 ± 1.28) and olive tail moment (0.54 ± 0.12), was recorded in Tf-supplemented samples stored for 48 h compared to that with no Tf. Hence, it is concluded that the beneficial effects of transferrin on common carp sperm could serve as an additional tool for developing and enhancing short-term sperm preservation procedures commonly used in aquaculture.