Aluminum at environmental concentrations affects the sperm quality of the freshwater teleost Astyanax altiparanae: An in vitro study.

Aluminum (Al) is present in rivers and reservoirs in concentrations above that is allowed by regulatory agencies (e.g. 0.5 mg L Al), which can impair fish reproduction. The present study evaluated the in vitro effects on the sperm of Astyanax altiparanae upon Al exposure at different concentrations (0, 0.05, 0.1, 0.3, and 0.5 mg L) with various exposure periods (50 s, 10 min, and 30 min). The following biomarkers were evaluated: membrane vitality, DNA fragmentation, morphology, kinetics (10 s and 30 s after sperm activation), and sperm mitochondrial activity. Al damages the membrane vitality of gametes at 0.3 and 0.5 mg L after 50 s of exposure. After 30 min of exposure, there was a decrease in membrane vitality at 0.1 and 0.5 mg L, and the membrane vitality decreased with increased exposure time. Within 30 s after sperm activation, Al (0.3 and 0.5 mg L) reduced sperm motility by more than 50% at the longest exposure time, while at 0.1 and 0.5 mg L, Al exposure reduced motility over time. The average path speed (VAP; 10 s post-sperm activation) was reduced at longer exposure times at 0.05 and 0.5 mg L of Al. Increased exposure time had deleterious effects on mitochondrial activity at the highest concentrations tested. Al did not damage DNA and sperm morphology. In conclusion, Al negatively influences the sperm quality of A. altiparanae with a potential effect of exposure time and increasing concentrations.