Determination of the best post-ovulatory stripping time in female rainbow trout Oncorhynchus mykiss

Subject Areas : Journal of Large Animal Clinical Science Research(JLACSR)

Received: 2021-07-11 Accepted : 2021-07-11 Published : 2009-12-22

Keywords: Oncorhynchus mykiss, Stripping, Ovulation, Abdominal cavity,

Abstract :

Considering few oocytes in female rainbow trout, Oncorhynchus mykiss, factors affecting egg quality are more important. Since post-ovulatory stripping time has been reported the most important factor affecting egg quality, the present study was performed to understand the best stripping time in female rainbow trout. Egg quality measurement was done through assessing the eyeing and hatching rates of eggs. One hundred females expected to ovulate in the near future were selected from the brood stock and stored at 2 ºc. Then serial judgments of ovulation were performed at 3-day intervals for 30 days. Ten groups of fish, each comprising of three females ovulating simultaneously, were held in separate tanks until fertilization. Other ovulated females were removed from the brood stock. All the females were fertilized at the end of the 30th day. So there were 10 groups presenting 10 different retention times until artificial fertilization. The eyeing and hatching rates for eggs fertilized immediately after ovulation (0-3 DPO) were 37.6 % and 31.5% (Mean ± SEM), respectively, which were significantly lower than those for eggs fertilized thereafter. Apart from these initially low values, the average eyeing and hatching rates were 85.15 % and 68.55 % during the post-ovulation period of 30 days.  Significant relationships were observed between the retention time and both the eyeing and hatching rates. The present study therefore demonstrates that immediately stripping after ovulation leads to lower egg survival and so, it seems necessary to retain oocytes in the abdominal cavity for a short period time after ovulation. Also, the best post-ovulatory stripping time was assessed at least 60 degree-days in female rainbow trout.

References:

1-      Aegerter, S. and Jalabert, B., (2004): Effects of post ovulatory oocyte ageing and temperature on egg quality and on the occurrence of triploid fry in rainbow trout. Oncorhynchus mykiss. Aquaculture, J. 231: 59-71.

2-      Bahrekazemi, M., Matinfar, A., Soltani, M., Abtahi, B., Pusti, I. and Mohagheghi, A., (2009): The relation between egg viability, selected aspects of egg and ovarian fluid composition and time of stripping in endangered Caspian brown trout, Salmo trutta caspius.Journal of Fisheries and Aquatic Science, 4 (6): 306-315.

3-      Bonnet, E., Jalabert, B. and Bobe, J., (2003): A 3-day in vitro storage of rainbow trout Oncorhynchus mykiss unfertilised eggs in coelomic fluid at 12 ^o C does not affect development success. Cybium, 27: 47-51.

4-      Bry, C., (1981): Temporal aspects of macroscopic changes in rainbow trout Salmo gairdneri oocytes before ovulation and of ova fertility during the post-ovulation period; effect of treatment with 17^α- hydroxy- 20β-dihydroxyprogesterone. Aquaculture, J. 24: 153-160.

5-      Craik, J. C. A. and Harvey, S. M., (1984): Biochemical changes associated with overripening of the eggs of rainbow trout, Salmo gairdneri. Aquaculture, J. 37: 347-357.

6-      Escaffre, A. M. and Billard, R., (1979): Changes in fertilizability of rainbow trout eggs left in the abdominal cavity during the post-ovulatory period. Bull. Fr. Piscic., 272: 56-70.

7-      Gaudemar, B. D. E. and Beall, E., (1998): Effects of overripening on spawning behaviour and reproductive success of Atlantic salmon females spawning in a controlled flow channel. J. Fish Biol., 53: 434-446.              

8-      Lahnsteiner, F., (2000): Morphological, physiological and biochemical parameters characterizing the overripening of rainbow trout eggs. Fish Physiol. Biochem., 23: 107-118.

9-      Mohagheghi Samarin, A., Ahmadi, M.R., Azuma, T., Rafiee, Gh. R., Mojazi Amiri, B. and Naghavi, M.R., (2008): Influence of the time to egg stripping on eyeing and hatching rates In rainbow trout oncorhynchus mykiss under cold temperatures. Aquaculture, J. 278: 195-158.

10-  Mylonas, C. C., Hinshaw, J. M. & Sullivan, C. V., (1992): GnRH-induced ovulation of brown trout Salmo trutta and its effect on egg quality. Aquaculture, J. 106: 379-392.

11-  Rime, H., Guitton, N., Pineau, C., Bonnet, E., Bobe, J. and Jalabert, B., 2004. Post-ovulatory ageing and egg quality: A proteomic analysis of rainbow trout coelomic fluid. Reprod. Biol. Endocrinol., 2(1): 26.

12-  Sakai, K., Nomura, M., Takashima, F. and Oto, H., (1975): The over-ripening phenomenon of rainbow trout: Changes in the percentage of eyed eggs, hatching rate and incidence of abnormal alevins during the process of over-ripening. Bull. Jap. Soc. Sci. Fish, 41 (8): 855- 860.    

13-  Springate, J. R. C., Bromage, N. R., Elliott, J. A. K. and Hudson, D. L., (1984): The timing of ovulation and stripping and their effects on the rates of fertilization and survival to eyeing, hatch and swim-up in the rainbow trout Salmo gairdneri. Aquaculture, J. 43: 313-322.  

14-  Wallace, R. A. and Selman, K., (1978): Oogenesis in Fundulus heteroclitus. Dev. Biol., 62: 354-369.

15-  Yamazaki, F., Goodier, J. and Yamano, K., (1989): Chromosomal aberrations caused by ageing and  hybridization in charr, masu salmon and related salmonids. Physiol. Ecol. Jpn. Spec., 1: 529-542.