Neucoendocrine regulation of reproduction in the marine female prawn, <i>Parapenaeopsis hardwickii</i> (Miers)

Abstract

Effects of bilateral eyestalk extirpation and injections of eyestalk (Es), brain (Br) and thoracic ganglia (ThG) extract on the ovarian development of eyestalkless and normal Parapenaeopsis hardwickii were investigated. There was a significant (P < 0.01) increase in the ovarian indices (OI) and oocyte diameters following Es ablation and injections of Br and ThG extracts separately in the eyestalkless prawns as compared to untreated controls. But the values of OI and oocyte diamters of eyestalkless prawns, which were injected with unboiled Es extract were not significantly (P > 0.05) different from those of untreated controls. There was a significant (P> 0.05) increase in total glycogen and fat concentrations and decrease in protein content of treated prawn ovaries as compared to those of controls. But changes in the biochemical parameters of ovaries of prawns treated with unboiled Es extract were not significantly (P <0.05) different from those of controls. In normal prawns, a significant (P < 0.01) hike in OI and oocyte diameters after the injections of Br (group D) and ThG (group E) extracts was observed as compared to the corresponding values of untreated controls (group A). But the values of OI and oocyte diameters of normal prawns injected with Es extract (group B) did not differ significantly (P > 0.05) from the values of control prawns in group A. A significant (P > 0.05) augmentation in total glycogen and fat content and decrease in protein quantity was noticed in the ovaries of prawns in groups D and E as compared to the ovaries of group A prawns. But variations in organic reserves of ovaries of group B prawns were not significantly (P > 0.05) different from the values of group A prawn ovaries (control).