Effect of bisphenol A exposure on the expressions of five ovary development related genes in the oriental river prawn, Macrobrachium nipponense (Decapoda, Palaemonidae)

Abstract

The oriental river prawn,Macrobrachium nipponense, is one of the important commercial shrimp species. Recently a severe problem of precocious maturation has greatly hampered this shrimp aquaculture industry. Bisphenol A (BPA), a high-production-volume chemical substance used in the plastic manufacturing industry, has been thought of as an endocrine disruptor on the developmental processes of animals. In this study, we investigated the effect of BPA exposure on the expressions of five ovary development related genes such as Mago nashi, Tsunagi, Gustavus, Ubc9, and Von Willebrand factor D-Kazal inM. nipponense. Five concentration gradients (5.01, 7.76, 12.06, 18.62 and 28.84 mg/l) of BPA were set and the ovaries of exposed prawns were collected at different time points for expression analysis. Compared with the control group at day 19, BPA had a two-phase effect: a stimulating effect under low concentrations from 5.01 to 12.06 mg/l, whereas a negative effect was noted at high concentrations from 12.06 to 28.84 mg/l. The expression profiles under different BPA concentrations significantly changed along with the extension of exposure time. The medium concentration of BPA (12.06 mg/l) had a persistent influence on the expressions of the transcripts, while the effect was transient under the lowest concentration (5.01 mg/l). It is suggested that the concentration under 5.01 mg/l might be safe for the development ofM. nipponense, but exceeding 12.06 mg/l may be harmful. When exposed to clean fresh water without BPA, the gene expressions rebounded a little. This may indicate that the biological damage of BPA was partly reversible after the prawns had been placed in the fresh water without BPA. So the BPA pollutant concentration should be controlled at secure levels in order to ensure safety in aquaculture, in this respect. This study provides fundamental data for the relationship between BPA and precocious maturation of the prawn, and will most probably contribute to the understanding of the sexual maturation process in crustaceans.