Energy resources of spermatozoa of the rainbow trout Oncorhynchus mykiss (Pisces, Teleostei)

Spermatozoa of Oncorhynchus mykiss have the enzymatic capacity for glycolysis, for triglyceride and phospholipid catabolism and triglyceride synthesis. They lack glucosidase activity and are therefore not able to utilize polysaccharides as energy resources. In motile spermatozoa glycolysis occurs during the first 30 s of motility and--when motility is initiated in a physiological saline solution--triglyceride catabolism is used for the regeneration of ATP levels after motility has ended. When immotile spermatozoa are incubated with the seminal plasma or in physiological saline solution they behave similarly as regards utilization of their primary energy reserves: glycolysis as well as catabolism of triglycerides occurs. In approximately 60% of the semen samples, spermatozoa synthesize triglycerides at the onset of incubation. Possible physiological reasons for triglyceride synthesis have been discussed.