Morphological abnormalities in cryopreserved semen from South American neotropical fish: A meta-analysis

A systematic review (SR) and meta-analysis (MA) were performed to summarize the scientific evidence of the effects of cryopreservation of sperm from South American freshwater fish species on sperm morphology indicators. The search strategy was applied to four electronic databases, and specialists were contacted electronically. The main inclusion criteria involved studies on neotropical fish whose male gametes were submitted for cryopreservation. MA for random effects was performed for each indicator separately with the averages of the control and treated groups. A total of five publications, which comprise five studies and 15 trials, were included in the MA involving three different species. Heterogeneity was observed among the studies for all variables. In general, the percentage of normal cells did not change significantly after cryopreservation. Primary morphological abnormalities increased significantly at a level of 1.91% (95% confidence interval [CI]: -3.727-0.097; p = 0.021) after cryopreservation when compared with fresh semen. The percentage of secondary abnormalities did not show a significant change (p >= 0.05) between fresh semen and cryopreserved semen. Our results suggest a new classification for sperm abnormalities in South American neotropical fish based on the increase in primary abnormalities after cryopreservation.

Automated summary

The study found that after cryopreservation of sperm from South American freshwater fish species, there was a significant increase in primary morphological abnormalities, while the percentage of normal cells did not change significantly. There was no significant change in the percentage of secondary abnormalities between fresh semen and cryopreserved semen.