Effect of ascorbic acid supplement in vitro on rainbow trout sperm viability

We evaluated motility and fertilizing ability of rainbow trout Oncorhynchus mykiss semen obtained from fish fed diets without ascorbic acid and a diet supplemented with 870 mg kg(-1) of ascorbyl monophosphate. Semen was store d in vitro on ice (0 degrees C) during 14 days. The spermatozoa from the su pplemented group had the highest motility and lowest decline in fertilizing ability after storage. Lack of a positive effect of exogenous vitamin C on semen in fish deficient in ascorbic acid (milt was supplemented with 50 mg l(-1) of ascorbic acid) suggests that the positive effect of ascorbic acid on semen quality is related to its long-term effects during spermatogenesi s.