Aim: The aim of this study was to investigate the effect of fish omega-3 fatty acids on some metabolic enzymes of rat testes.

Material and method: Wistar albino rats were divided into two groups. Rats of experimental group (n=9) were supplemented fish omega-3 fatty acids as 0,4g/kg bodyweight by gavage for 30 days in addition to their normal diet. Isotonic solution was given to the control group (n=8) by the same way. At 30th day, the rats were killed by decapitation under ether anesthesia, autopsied and testes was removed. Spectrophotometric methods were used to determine the activities of glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), lactate dehydrogenase (LDH), malate dehydrogenase (MDH) and hexokinase (HK) enzymes in the testes tissues.

Results: The fish omega-3 fatty acids caused increases in the activities of G6PD, 6PGD, LDH, MDH, and HK in comparison with control. In the MDH increase was statistically significant.

Conclusions:Omega-3 fatty acids increase the HK, G6PD, 6PGD, and LDH enzyme activities insignificantly and MDH enzyme activity significantly. The mechanism of this effect is not clear. We suggested that omega-3 fatty acid affects energy protection system positively by increasing MDH enzyme activities, which is a member of energy protection cycle.