Feeds supplemented with L-carnitine and varying oil sources improve the Rhamdia quelen thawed sperm redox balance and...

Nutritional management of fish using different oil sources and L-carnitine could be an advantageous strategy to improve the quality of spermatozoa and their capacity to tolerate the aggressive damage imposed by the cryopreservation process. This is an interesting approach because of the effects of L-carnitine on lipid mobilization during energy metabolism, fatty acid deposition, and modulation of lipid peroxidation and protein carbonylation. In this study, we aimed to feed Rhamdia quelen males L-carnitine and various oil sources and to evaluate the effect on cryopreserved sperm quality, spermatozoa movement, and redox balance parameters. Over 223 days, using a bi-factorial experimental design, fish (167.33 ± 9.24 g) were fed eight rations containing combinations of 0, 150, 450, and 750 mg L-carnitine kg^-1, along with soybean and marine fish oils. Males fed 150 mg L-carnitine kg^-1 independent of oil source, produced the most motile thawed spermatozoa (p < 0.05). Males fed 150 mg L-carnitine kg^-1 and fish oil, or 0 mg L-carnitine kg^-1 and soybean oil, produced thawed spermatozoa with the lowest (p < 0.05) lipid peroxidation, and those fed 750 mg L-carnitine kg^-1 and fish oil the lowest (p < 0.05) protein carbonylation. Male Rhamdia quelen fed diets supplemented with 150 mg kg^-1 of L-carnitine and fish oil produced spermatozoa with enhanced lipid integrity, which was attributable to reduced lipid peroxidation in sperm cells. Consequently, these males may yield improved outcomes after artificial fertilization because they exhibit superior sperm motility.