Transcriptome Analysis Reveals Key Gene Expression Changes in Blue Catfish Sperm in Response to Cryopreservation

Abstract

The hybrids of female channel catfish (Ictalurus punctatus) and male blue catfish (I. furcatus) account for >50% of US catfish production due to superior growth, feed conversion, and disease resistance compared to both parental species. However, these hybrids can rarely be naturally spawned. Sperm collection is a lethal procedure, and sperm samples are now cryopreserved for fertilization needs. Previous studies showed that variation in sperm quality causes variable embryo hatch rates, which is the limiting factor in hybrid catfish breeding. Biomarkers as indicators for sperm quality and reproductive success are currently lacking. To address this, we investigated expression changes caused by cryopreservation using transcriptome profiles of fresh and cryopreserved sperm. Sperm quality measurements revealed that cryopreservation significantly increased oxidative stress levels and DNA fragmentation, and reduced sperm kinematic parameters. The present RNA-seq study identified 849 upregulated genes after cryopreservation, including members of all five complexes in the mitochondrial electron transport chain, suggesting a boost in oxidative phosphorylation activities, which often lead to excessive production of reactive oxygen species (ROS) associated with cell death. Interestingly, functional enrichment analyses revealed compensatory changes in gene expression after cryopreservation to offset detrimental effects of ultra-cold storage: MnSOD was induced to control ROS production; chaperones and ubiquitin ligases were upregulated to correct misfolded proteins or direct them to degradation; negative regulators of apoptosis, amide biosynthesis, and cilium-related functions were also enriched. Our study provides insight into underlying molecular mechanisms of sperm cryoinjury and lays a foundation to further explore molecular biomarkers on cryo-survival and gamete quality.

Cryopreservation Studies in Aquaculture from Past to Present: Scientific Techniques and Quality Controls for Commercial Applications

“…Cryopreservation has been shown to have detrimental effects on the plasma membrane, mitochondria, chromatin structure, osmotic control, and spermatozoa motility [93,94]. The cryopreservation process can lead to apoptosis and mitochondrial dysfunction [95], and studies have been carried out at the molecular level in recent years to determine the effect of cryoinjury [96,97]. After thawing, sperm motility parameters in most species, including I. furcatus, show a decrease.…”

“…This reduction in motility parameters can reduce fertilization potentials and three times higher oxidative stress level has been determined. It indicates that sperm quality may deteriorate after cryopreservation due to a 4-fold increase in the DNA fragmentation level of sperm after thawing [96]. One of the effects of cryopreservation on sperm cells is the increase of apoptotic cells [98,99].…”

“…In these analyses, upregulated genes were identified in sperm samples after thawing and an increase in oxidative phosphorylation activities leading to excessive production of ROS associated with cell death was detected. Despite these negative results, the presence of the potential of sperm to fertilize eggs after thawing is expressed in the fact that compensatory processes occur in the gene expression of sperm cells after thawing to offset these harmful effects (MnSOD, induction to control ROS production; correction of misfolded proteins; apoptosis, functions related to amide biosynthesis) [96]. Sperm cryopreservation can affect several biological processes, including apoptosis, spermatogenesis, mitochondrial activity, ROS production, amide biosynthesis, protein folding, and degradation [96].…”

“…Despite these negative results, the presence of the potential of sperm to fertilize eggs after thawing is expressed in the fact that compensatory processes occur in the gene expression of sperm cells after thawing to offset these harmful effects (MnSOD, induction to control ROS production; correction of misfolded proteins; apoptosis, functions related to amide biosynthesis) [96]. Sperm cryopreservation can affect several biological processes, including apoptosis, spermatogenesis, mitochondrial activity, ROS production, amide biosynthesis, protein folding, and degradation [96]. Therefore, the effect of cryopreservation is quite complex, with both harmful and compensatory effects on Cryopreservation Studies in Aquaculture from Past to Present: Scientific Techniques and Quality… DOI: http://dx.doi.org/10.5772/intechopen.108566 sperm quality.…”

Paternal-effect-genes revealed through sperm cryopreservation in Perca fluviatilis

“…Cryobanking of milt helps to manage the genetic diversity of the fish species, facilitates spawning synchronization, allows selective breeding and much more 20 . Cryopreservation of milt is a big shock to a sperm cell constituting a specific challenge test 21 which causes irreversible damages to the cryo-sensitive cells which lose fertilizing capacity, in contrast to cryo-resistant cells retaining their functionality 22 . Importantly, the effect of cryopreservation on spermatozoa functionality depends on the species.…”