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Relationship between seminal plasma composition and spermatozoa swimming speed and motility in wild and captive shortnose sturgeon (Acipenser brevirostrum)

Gilroy, Christine E., Litvak, Matthew K.
Aquaculture 2019 v.505 pp. 217-224
Acipenser brevirostrum, aquaculture, calcium, cluster analysis, osmolality, pH, potassium, principal component analysis, seminal plasma, sodium, sperm motility, sperm quality, swimming, wild fish
We analyzed seminal plasma composition of 27 shortnose sturgeon (Acipenser brevirostrum) from both captive and wild populations. Osmolality, pH, sodium, potassium, chloride, and calcium were measured as possible predictors of spermatozoa swimming velocity and percent motility, which are proxies for sperm quality. Principal components analysis resulted in two interpretable components that explained 74% of the variation in the data. The first principal component, PC1, was positively loaded with sodium and potassium, and negatively loaded with chloride. The second principal component, PC2, was positively loaded with calcium and osmolality, and negatively loaded with pH. There were significant differences in seminal plasma composition between wild and captive sourced sperm for both main components (PC1 p-value = .00229, PC2 p-value = .00304), with captive fish having lower sodium, potassium, and osmolality, and higher chloride than wild fish. Cluster analysis of PCA data resulted in three distinct clusters that were characterized by source (p-value = .00458). All subsets regressions showed that seminal plasma sodium content was the best single predictor for swimming velocity and percent motility of both captive and wild sourced sperm. These differences in seminal plasma composition could be contributing to the observed lower quality sperm from captive individuals in this species. Information presented here provides insight on shortnose sturgeon reproduction for both conservation and aquaculture programs.