Induction of diploid gynogenesis in turbot Scophthalmus maximus with left-eyed flounder Paralichthys olivaceus sperm

Abstract

Turbot Scophthalmus maximus exhibits sexually dimorphic growth, with females growing faster and reaching larger adult sizes than males. Thus, development of techniques for preferentially producing females is necessary to optimize production of these species. In this paper, gynogenetic diploids of turbot were induced by activating egg development with ultraviolet (UV)-irradiated left-eyed flounder Paralichthys olivaceus sperm combined with cold shock to prevent extrusion of the second polar body. The results of UV irradiation experiments showed that survival, motility, and duration of activity of P. olivaceus sperm generally decreased with increase in UV dose. The typical Hertwig's effect was observed after fertilized turbot eggs with UV-irradiated P. olivaceus sperm and the optimal UV dose for gynogenetic haploid production was 36,000 erg mm -2 . At 15°C, appropriate timing of cold shock for retention of the second polar body in turbot eggs was at 6 min after fertilization. Results of different combinations of two shock temperatures (1 or 3°C) and four shock durations (15, 25, 35 or 45 min) at 6 min after fertilization demonstrated that shock of 25 min at 1°C gave the highest production of diploid gynogens (39.58% relative to its diploid control). The results of this study reveal that the use of UVirradiated P. olivaceus sperm for activation of turbot eggs and cold shock for polar body retention is an effective method to produce gynogenetic offspring.

Artificial gynogenesis and assessment of homozygosity in meiotic gynogens of spotted halibut (Verasper variegatus)

“…In addition, frozen sperm of one fish species can be used to induce gynogenesis in many species of fish because we can obtain frozen sperm at any time within 1 year. Although many heterologous sperms have been used to induce gynogenesis of fish, such as large-scale loach , turbot (Xu et al 2008), sterlet Acipenser ruthenus (Fopp-Bayat et al 2007), and tench Tinca tinca (Wang et al 2006) in recent years, there is very little reports on induction of diploid gynogenesis using heterologous frozen sperm ).…”

Breeding studies on red sea bream Pagrus major: mass selection to genome editing

“…Gynogenetic diploids have been produced in many fish species (Ihssen et al 1990;Arai 2001;Manan et al 2022). In saltwater aquaculture species, gynogenetic diploids have been produced in red sea bream (Kato et al 2001a(Kato et al , b, 2002, Japanese flounder Paralichthys olivaceus (Tabata 1991;Yamamoto 1999Yamamoto , 1995, European sea bass Dicentrarchus labrax (Peruzzi and Chatain 2000;Peruzzi et al 2004;Bertotto et al 2005), turbot Scophthalmus maximus (Piferrer et al 2004;Cal et al 2006;Xu et al 2008;Meng et al 2016;Wu et al 2020), and gilthead sea bream (Gorshkova et al 1998), although few reports examined the growth and survival rate of gynogenetic diploids based on long-term rearing (Tabata 1991;Yamamoto 1999Yamamoto , 1995Peruzzi et al 2004;Bertotto et al 2005;Cal et al 2006;Wu et al 2020).…”

The effect of sexual dimorphism on growth of the black sea turbot, Psetta maxima

“…Maturing females can reach 1.8 kg in 20 months whereas the weight of males only reaches around 1 kg. Thus, as is practiced with other cultured species, the development of techniques for preferentially producing female turbot is necessary to optimize production of this species (Xu et al 2008).…”