Determination of Triploidy in Rainbow Trout, Oncorhynchus mykiss using Erythrocyte Measurements

Abstract

In this study, effects of thermal shock (26°C) on Oncorhynchus mykiss egg at different duration time (5, 10, 15 and 20 min.) to triploid rate was determined. Level of triploid induction for each treatment was evaluated by erythrocyte measurements. For this purpose, the caudal peduncles of 40fry for each group were cut off and blood smears prepared. The cell and nucleus lengths (major and minor axis) of 30 erythrocytes for each individual were determined with the aid of a microscope camera (with ScopImage 9.0®) and using a micrometer. There was considerable variation in major axisof erythrocytes cell and nucleus both within individual fish and among individuals of a given ploidy. In the major axis length of erythrocyte, cell and nucleus of 10, 15, 20 min thermal shocked groups were statistically significant compared to the control groups (p<0.05). The presented study demonstrated that the increases of triploid yields are correlated to length oferythrocyte major axis. In conclusion, the best triploid yield for O. mykiss was at 26°C for 15 min initiated 15 min after fertilization.

Keywords

• Rainbow trout (Oncorhynchus mykiss), Heat shock, Triploid (3n), Diploid (2n), Erythrocyte measurements

References

1. Benfey, T. J., and A. M. Sutterlin. 1984. The Haematology of Triploid Landlocked Atlantic Salmon Salmo salar (L.). Journal of Fish Biology, 24: 333-338.
2. Benfey, T., Sutterlin, A., and R. Thompson. 1984. Use of Erythrocyte Measurements to Identify Triploid Salmonids. Canadian Journal of Fisheries and Aquatic Sciences, 41: 980–984.
3. Boron, A. 1994. Use of Erythrocyte Measurements to Detect Natural Triploids of Spined Loach Cobitis taenia (L.). Cytobios 78: 197–202.
4. Diaz, N. F., Iyurra, P., Veloso, A., Estay, F., and N. Colihueque. 1993. Physiological Factors Affecting Triploid Production in Rainbow Trout. Aquaculture 114: 33–40.
5. Dorota, F. B., Jankunand, M., and P. Woznicki. 2006. Chromosome Number and Erythrocyte Nuclei Length in Triploid Siberian Sturgeon Acipenser baeri Brandt. Caryologia 59: 319-321.
6. Espinosa, E., Josa, A., Gil, L., and J.I. Marti. 2005. Triploidy in Rainbow Trout Determined by Computer-Assisted Analysis. Journal of Experimental Zoology 303: 1007–1012.
7. Garcia-Abiadoa, M. A. R., Dabrowskia, K., Christensena, J. E., Czesnya, S., and P. Bajerb. 1999. Use of Erythrocyte Measurements to Identify Triploid Saugeyes. North American Journal of Aquaculture 61: 319-325.
8. Howel, W. H., and D. A. Black. 1980. Controlled Silver Staining of Nucleolus Organizer Regions with a Protective Colloidal Developer: a One-Step Method. Experientia 36: 1014–1015. Johnstone, R., and R. F. Lincoln. 1986. Ploidy Estimation Using Erythrocytes from Formalin Fixed Salmonid Fry. Aquaculture 55: 145-148.

9. Liu, S., Sezaki, D., Hashimoto, K., Kobayashi, H., and M. Nakamura. 1978. Simplified Techniques for Determination of Polyploidy in Ginbuna, Carassius auratus Langsdorfi. Bulletin of the Japanese Society for the Science of Fish. 44: 601–606.
10. Moffett, I. J. J., and W. W. Crozier. 1995. An Investigation into the Reproducibility of Triploid Brown Trout, Salmo trutta L., Production using Heat Shock. Aquaculture Research, 26: 67–70. Pradeep, P. J., Srijaya, T. C., Jose, D., Papini, A., Hassan, A., and A.K.
11. Anil Chatterji. 2011. Identification of Diploid and Triploid Red Tilapia by using Erythrocyte Indices. Caryologia, 64: 485-492.
12. Purdom, C. E. 1993. Genetics and Fish Breeding. Chapman & Hall, London.
13. Siyang, L., and L. Suwen. 1987. On the Erythrocyte Nucleus Size and DNA Contents of Ctenopharyngodon idellus, Megalobrama terminalis and F, Hybrid. Acta Genetica Sinica, 14: 142-148.
14. Thorgaard, G. H. 1983. Chromosome Set Manipulation and Sex Control in Fish. In: Hoar, W.H., Randall, D.J., Donaldson, E.M. (Eds.), Fish Physiology. Vol. IXB. Academic Press, New York, pp. 405–434.
15. Woznicki, P., and H. Kuzminski. 2002. Chromosome Number and Erythrocyte Nuclei Length in Triploid Brook Trout (Salvelinus fontinalis). Caryologia, 55: 295-298.