Triploidy induction by hydrostatic pressure shock in mandarin fish (Siniperca chuatsi)

Abstract

The mandarin fish, Siniperca chuatsi, is a kind of ferocious carnivorous fish, which has highly economic value with the characteristic of rapid growth and delicious flesh. Large scale industrial breeding of mandarin fish has been realized widely in China. The triploid in mandarin fish S. chuatsi had been induced by hydrostatic pressure shock. The most effective condition of triploidy induction was initiation of pressure treatment 6 min after fertilization, duration of treatment 2 min and magnitude of pressure 450 kg/cm2 in which could result in 72% triploid fish. There were no significant differences of the survival of triploid rates among the three treatment groups, which include holding for 4 min, 6 min, and 8 min after fertilization. The efficiency of triploidization was confirmed by counting the number of chromosomes and was affirmed by DNA content determination using flow cytometry with blood cells of one-month old fingerlings. The chromosome count of induced triploids was 3n = 72 while diploid fish had 2n = 48. The flow cytometry shows that DNA content in experimental group was 1.5 times as the control group. In conclusion, this paper presents optimal conditions for triploidy induction in mandarin fish with hydrostatic pressure shock, which will contribute to promote the progress of breeding industry and enhance the production of mandarin fish in culture.