The effects of different times of reproductive migration on biochemical compounds of ovarian fluid and on fertilization rate of Persian sturgeon (Acipenser persicus) brood stocks

In this study we investigated the effects of different times of reproductive migration on biochemical compounds fluctuation (calcium, magnesium, glucose, cholesterol, total protein, sodium and potassium) and on the percentage of haematocrit of coelomic fluid and on the fertilization rate of 14 Persian sturgeon brood stocks, during the spawning season (in March of 2008 until May of 2008). For this purpose, the period of sampling was divided to three groups, beginning (March), middle (April) and end (May) of spawning season of these fishes. The average of fork length and total weight of fishes before extraction of eggs of Persian sturgeon brood stocks in treatments 1, 2 and 3 were 166.5 ± 6.36, 156.71 ± 8.69 and 174.5 ± 2.12 cm, also 33.0 ± 1.41, 30.1 ± 7.19 and 34.5 ± 0.70 kg, respectively. On the other hand, the average of percentage of fertilization rate in treatments 1, 2 and 3 were respectively 166.5 ± 6.36, 156.71 ± 8.69 and 174.5 ± 2.12 cm, 33.0 ± 1.41, 30.1 ± 7.19 and 34.5 ± 0.70 kg , 67.5 ± 6.36, 68.3 ± 17.86 and 49.5 ± 3.53 percent. Our results showed that there were significant differences in calcium (5.41±0.51 - 1.65±0.03 and 11.99±1.41 mg dL-1), glucose (37.99±15.10 - 23.61±6.45 and 11.3±3.26 mg dL-1), cholesterol (15.55±3.79 - 8.26±2.25 and 10.33±1.88 mg dL-1) and sodium (185.94±38.86 - 103.98±31.78 and 180.75±6.47 mM L-1) between these treatments (P0.05). Overall, significant and insignificant fluctuations in coelomic fluid in spawning season of these fishes demonstrated that ovarian fluid in treatments number 1 (March) and 3 (May) had better characteristics for sperm mobility compared to treatments 2 (April).