Examination of the Effects of Thoracic Ganglion and Brain Extracts on Vitellogenin Gene Expression in the Ovary of Whiteleg Shrimp, Litopenaeus vannamei, and Possible Vitellogenesis-Stimulating Activity

In order to examine the role of the central nervous system in regulating ovarian maturation in the whiteleg shrimp, Litopenaeus vannamei, we incubated ovarian explants taken from adult shrimp with either brain or thoracic ganglion extracts at the level of five tissue equivalents for 6 h. For assessment of the effects of each tissue extract, transcriptional expression of vitellogenin mRNA in incubated ovarian tissue fragments was analyzed by quantitative real-time PCR. Results showed that crude brain extracts and a 90% aqueous acetonitrile eluate upregulated expression levels in a significant manner. These findings suggest that factors originating from brain tissue are involved in ovarian maturation, but that the thoracic ganglia do not likely harbor significant quantities of stimulatory substances. In the future, this knowledge may be useful in developing technology for inducing maturation and spawning in captive female penaeid.