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Aspects of sperm motility and metabolism are important for understanding gamete quality. The objectives of this study were to investigate changes in adenosine 5′-triphosphate (ATP), and lactate dehydrogenase (LDH) of Atlantic cod sperm over time following activation, and to determine if initial semen parameters (ATP, LDH, Na+, K+, Ca2+, total protein, osmolality, pH, and spermatocrit) are indicative of sperm quality. Analyses of ATP and LDH were also performed on sperm cells at 0.5, 2, and 90 min post-activation, while sperm activity was recorded at 0.5 and 2 min. Initial semen parameters did not appear to be strong indicators of sperm quality but some correlations were observed between pH, LDH, K+, and protein and motility parameters in the first two min post-activation. The lack of significant correlation may be attributed to the low variability of almost all parameters observed between males in this study. There was a significant effect of post-activation time on sperm ATP and LDH with both ATP and LDH decreasing with time after activation. The decrease in ATP levels during the course of sperm motility suggests that the metabolic activity is too low to substitute the energy consumed. Continued research on sperm motility and metabolism will lead to a better understanding of fertilization and gamete quality in this species. [ABSTRACT FROM AUTHOR]

The in vitro effect of produced water released by oil and gas platforms was assessed by exposing cod sperm cells to realistic concentrations of this mixture (100, 200, 500 ppm). We investigated produced water impact on enzymes of the aerobic (citrate synthase) and glycolytic metabolism (lactate dehydrogenase), lipid catabolism (lipase), as well as an anti-oxidant enzyme (catalase). Fertilization rates, viability, respiration, ATP, and total motility duration were also evaluated. To explore correlations between these parameters, we have also tested the effect of conserving sperm for 24 h at 4°C. After conservation, fertilization success was decreased but other parameters were not affected. Produced water did not result in a significant change in fertilization; a significant increase in sperm protein amounts and citrate synthase activity can be observed. No correlations are found between parameters showing that sperm viability and unchanged energy levels do not translate into equivalent fertilization capacity. To conclude, exposure of sperm to produced water resulted only in subtle effects on cells. These findings bring information on the effect of produced water on sperm itself rather than on spermatogenesis or testis development of an exposed fish. [ABSTRACT FROM AUTHOR]