Browsing by Author "Güllü, K."

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Adaptation To Sea Water and Growth Performance of Rainbow Trout, Oncorhynchus Mykiss
(2006) Güner, Y.; Özden, O.; Güllü, K.
The Na+-K+-ATPase enzyme activity in gill tissues, changes of plasma ions level and, survival and growth performances of rainbow trout, Oncorhynchus mykiss, were investigated after gradual and direct acclimatization to high saline water in the Aegean Sea. Five experiments were performed with rainbow trouts weighing 120, 140, 160, 200 and 225 g. In this experiment, Na+, Cl-, K+, Ca+ and Mg+2 ion levels in blood plasma, Na+-K+-ATPase enzyme activities in gill tissues of rainbow trouts weighing 160 g in both freshwater and saltwater were measured. After adaptation to seawater, fish were held in marine cages of 64 m3 volume to grow up at Island of Urla-Karantina. Rainbow trouts weighing 120, 140, 200 and 225 g were reared in these cages for 80 days. Parallel to that, fish weighing 225 g were stocked in freshwater for comparison. The best survival percentage among directly acclimatized rainbow trouts was seen in 200-225 g fish, whereas the survival percentage among gradually acclimatized trouts presented similar results in every group. It can be concluded from these studies that, rainbow trout in certain seasons (Autumn-Winter) can adapt to the Aegean Sea condition (3.6-3.7%) and show good growth performance. © 2006 Asian Network for Scientific Information.
Effect of Estradiol Valerate Applied by Immersion and Oral Administration on Growth and Sex Reversal of Rainbow Trout, Oncorhynchus Mykiss
(Asian Network for Scientific Information, 2005) Güllü, K.; Güzel, Ş.; Güner, Y.
This study aimed to investigate the effects of exogenous estradiol valerate (E2V) applied by both immersion method and oral administration to produce monosex females on the growth of rainbow trout (O. mykiss). This study was conducted throughout 5 periods and 140 days. The rainbow trout fry (35 days old, post hatch) were immersed in a 400 μg L-1 of E2V solution for 2 h, twice a week for 4 weeks. Then fry were fed with a diet containing 20 mg kg-1 of E2V for 60 days. At the end of the study, E2V treatments were found to be effective for altering sex ratios of rainbow trout. Female production rate was determined as 100% in the E2V group. Results of the present study indicated that E2V reduced the growth, the food conversion rate and the survival rate of rainbow trout fry. However, it was positively effective to produce all female population of the rainbow trout. © 2005 Asian Network for Scientific Information.
The Effect of Estradiol Valerate on Sex Reversal of Rainbow Trout, Oncorhynchus Mykiss
(Asian Network for Scientific Information, 2006) Güzel, S.; Güllü, K.; Özden, O.
The effect of oral administration of 20 mg of estradiol valerate (E 2V) per kilogram of administered diet was studied on sex reversal in 35-day-old (average 0.32±0.02 g) rainbow trout, Oncorhynchus mykiss. The E2V was treated for 56 days to fry. The research was carried out totally 355 days. At the end of this time, all fish were sampled, digested and analyzed for their sex determination and the Gonadosomatic Index (GSI) values of the E2V and control groups were calculated. Compared to controls, there were changes in sex composition of E2V treated fish. The sex composition of E2V treated fish was found as 97% of female and 3% inter-sex. However it was found as 51 % of female and 49% male in the control fish. Gonadosomatic indices of the E2V and control groups were calculated as 0.12 and 4.21%, respectively. It was concluded that the determined application time, dose and period of E2V in this study were effective in direct feminization of rainbow trout. © 2006 Asian Network for Scientific Information.