L-carnitine solution used on Rhamdia quelen thawed sperm activation boosts sperm movement, maintains larval quality, and permits to optimize the sperm use.

The activation of cryopreserved sperm with solutions containing L-carnitine can improve sperm quality after thawing, owing to its involvement in several metabolic pathways. Sperm movement and viability for fertilization, hatching, and larval normality were assessed in Rhamdia quelen thawed sperm activated with L-carnitine solutions. Sperm from 24 males were cryopreserved in 0.25 mL straws. After thawing, the sperm movement was assessed by CASA (Computer-Assisted Sperm Analysis) in samples activated with distilled water containing 0.0 (control), 47.8, 96.2, 144.5, 192.3, and 240.7 mM L-carnitine, and another one with 79.9 mM D-fructose (control). Sperms from another 24 males were cryopreserved in an identical manner and used in the fertilization assays. Considering the sperm movement, fertilization assays were carried out using 0.0, 96.2, and 144.5 mM L-carnitine, and 79.9 mM D-fructose solutions. Greater motility and velocity were achieved with 144.5 mM L-carnitine at 28 and 18 s after activation, respectively. Linearity was not affected by time. The greater mean motility was provided by 144.5 mM as well as the greater mean velocity and linearity by 192.3 mM L-carnitine. Fertilization and hatching were not influenced; however, 144.5 mM L-carnitine and 79.9 mM D-fructose solutions produced more normal larvae. In summary, the L-carnitine solution increased sperm movement and maintained larval quality and production, similar to a conventional fructose activation solution.