The effect of different parameters on short-term storage capacity of turbot ova was assessed over a 45-h period after ova collection for fertilization rates and over a 9-h period after ova collection for hatching rates. Increasing the volume of ova sampling from 0.5 to 2.5 mL, as well as adding an antibiotic-antimicotic solution or oxygen did not significantly change the storage capacity of ova. Regarding the hatching rates, a higher storage ability was recorded at 8 and 13 °C, compared to 3 °C. The mean composition of the ovarian fluid was determined (n = 57 spawns). Use of a diluent mimicking the ovarian fluid significantly decreased the storage ability as assessed by the fertilization rates but did not modify the hatching rates. Diluting ova in an artificial ovarian fluid deprived of calcium significantly decreased the fertilization and hatching rates during the storage period. Furthermore, addition or not of soybean trypsin inhibitor (Sigma T 9003) to the artificial ovarian fluid deprived of calcium did not significantly change the results. Storage capacity of control batches of ova was low: at 13 °C, without any diluent and when ova were fertilized 3 h after stripping, the hatching rate was lowered to 62.4 ± 29.4 % (mean ± SD) of the initial value.

In this study an attempt was made to develop a suitable diluent based on the characteristics ofgood quality ovarian fluid of Oncorhynchus mykiss. The resulting simulated ovarian fluid (SOF) was compared with Borax-borie acid buffer diluent and adjusted versions thereof. The composition of al1 these diluents are given in this paper. Maximum fertilization success (81.76%) was achieved when ovarian lluid was employed as a sperm diluent. Spermatozoa showed maximum (34 seconds) forward motility after dilution with Borax 3. The use of diluents in artificial fertilization techniques by trout farmers can help them to increase the fertilization success and also facilitates hatchery procedures and broodslock management.