Optimization of triploid induction by the use of 6-DMAP for the oyster Crassostrea gigas (Thunberg)

Abstract

Abstracl. A nove! mcthod using 6-dimcthylaminopurinc (6-0MAP) has rcccntly bccn dcmonstrated to bc a good triploid inductor for bivalvc molluscs. Thc cffccts of 6-0MAP concentration, timing of trcatment aftcr fertilization. and treatment duration on survival and triploid induclion of Crassastrea gigas (Thunberg) embryos wcre examined. A.n influcnce of sperm concentration was also detected and discussed. Survival loO-stage was invcrscly re!ated to 6-0MAP concentration and the percentage of triploids was shown to bc 6-0MAP dose dependenl. Two optimal moments for treatment application were delcrmined. cor rcsponding to extrusions of the firsl and sceond polar bodies. Optimal treatment of 450 pmolll 6-0MAP bcginning 15 min after fertilization over a lOmin period yiclded mcan survival to O-stagc of 64% with a mean of 85% triploid production. As a comparison, a sample trcated with 1 mg/l of cytoehalasin B (CB). 20 min aftcr fertilization over a 15 min pelriod, yieldcd a me an survival to O-stage of only 36% with a mean of 95% triploid production. The advantages of 6-0MAP ovcr CB arc clearly identified: this chemical is noll carcinogcnic, cheapcr than cytochalasin Band much casier to use as it is water soluble.

Effect of three triploidy induction methods on the growth and survival of larvae and post-larvae of the Caribbean scallopArgopecten nucleus

“…This suggests that results can be improved by optimizing the induction protocols (Surier et al, 2007;Toro et al, 1995). (Desroisers et al, 1993;G erard, Naciri, Peignon, Ledu, & Phelipot, 1994). The percentage of triploid larvae obtained in the present study is similar to that reported in Crassostrea gigas (22%-57%) using this 6-DMAP at higher concentrations (390-450 lM/L) and a similar exposure time (Melo, Gomes, Silva, S€ uhnel, & Melo, 2015).…”

“…The treatment with 6‐DMAP (300 μM/L for 15 min) resulted in the best induction efficiency/effectiveness with a 39% of A. nucleus triploid larvae. This chemical inhibits the phosphorylation of proteins required in the process of tubulin microtubules polymerization and formation of the spindle apparatus through which segregation of the chromosomes during cellular division occurs (Dufresne, Néant, Saint‐Pierre, Dubé, & Guerrier, ; Rimme, Neant, Guerrier, & Ozon, ; Szöllösi et al., ), thus inhibiting the formation of polar bodies (Desroisers et al., ; Gérard, Naciri, Peignon, Ledu, & Phelipot, ). The percentage of triploid larvae obtained in the present study is similar to that reported in Crassostrea gigas (22%–57%) using this 6‐DMAP at higher concentrations (390–450 μM/L) and a similar exposure time (Melo, Gomes, Silva, Sühnel, & Melo, ).…”

Effects of salinity and temperature on the timing of germinal vesicle breakdown and polar body release in diploid and triploid Hong Kong oysters, Crassostrea hongkongensis , in relation to tetraploid induction

“…Using stripped gametes is more expedient and practical for producing tetraploids than using spawned oocytes because the time of fertilization and duration of treatment can be easily controlled (Jose & Meredith, ). Synchronization of meiosis of eggs is critical for the induction ratio of tetraploid and triploid oysters (Downing & Allen., ; Gerard, Naciri, Peignon, Ledu, & Phelipot, ). For example, Downing and Allen () used stripped eggs of C. gigas for triploid induction by CB, and large differences in survival and triploid ratio were discovered.…”

“…50% PB1 release is an obvious sign to begin the induction process in polyploidy production. In triploid induction of Hong Kong oysters by inhibiting PB2 release of diploid or triploid zygotes, the timing of 50% PB1 expulsion is an indicator to start treatment (Gerard et al, ; Qin et al, ). Tetraploid C. gigas were first successfully produced in 1994 by inhibiting PB1 release of eggs from triploids that had been fertilized with sperm from diploids (Guo & Allen, ).…”

Comparison of taste components between triploid and diploid oyster

“…Many research work were put on the inducement of triploid. In the mid of 1980s, triploid oyster was induced and cultured (Gerard, 1994). In the meantime, researchers all over the world began their work on the physiology and biochemistry of the soft body of the triploid oyster.…”