Livestock Studies 2003, Vol 43, Num, 2     (Pages: 025-034)

Freezıng And Evaluatıon Of Rainbow Trout (Oncorhynchus mykiss) Semen

Mesut ÇEVİK 1 ,Ali DAŞKIN 2

1 Hayvancılık Merkez Araştırma Enstitüsü Lalahan/ANKARA
2 Ankara Üniversitesi Veteriner Fakültesi Dölerme ve Sun'i Tohumlama A.B.D. Dışkapı/ANKARA
- In this experiment, the sperm characteristics of Rainbow trout and the correlations between these parameters were assessed. Furthermore, after the semen was frozen by two different extenders (diluent I and II), considerable post-thaw sperm characteristics and the influence of extenders on sperm viability were determined. 24 ejaculates of randomly selected Rainbow trout were used in freezing process. The sperm characteristics [semen volume (ml), sperm concentration (x 109 /ml), sperm motility (%) and pH] were determined in Rainbow trout semen collected by massage method. Semen of the Rainbow trout were cryopreserved in liquid nitrogen vapour using two different extenders.

In experiment, totaly 24 ejaculates collecting from Rainbow trout males were treated with regard to principle spermatological characteristics. Ejaculate volume averaged 19.75±2.07 ml, sperm motility 89.58±1.04%, sperm concentration 12.71±6.37 x 109 /ml and sperm pH 7.02±0.02 were established in fresh semen. Negative correlation (p<0.05) was observed between semen volume and sperm concentration.

In the results of examinations, the post-thaw sperm motility and pH in the first diluent were 77.08 % and 6.85 %, the same values in the second diluent were 72.50 % and 6.79 % respectively. Statistically significant (p<0.05) differences were observed between two extenders in term of motility.

In the applications of artificial insemination by frozen semen, respective tests were carried out for the I and II diluents. The results were evaluated by counting the `eyed egg` on the egg which occured in 15 days after fertilization. And the percentage of fertilization results for the I and II diluent were 56.08 % and 50.05 % respectively.

The results of this experiment, suggested that Rainbow trout semen could be frozen and BSA supplemented semen is more beneficial than without BSA for the rainbow trout due to post-thaw motility and fertilization results. Keywords : Rainbow trout, semen, cryopreservation, fertilization, artificial insemination