Silencing and augmentation of IAG hormone transcripts in adult males affects morphotype transformation.

Morphotypic differentiation is the external manifestation of dominance hierarchy in The intermediate morphotype orange claw (OC) male exhibits the highest growth rate and is subordinate in hierarchy to blue claw (BC) male while dominant on small male (SM). The present study was undertaken to examine the specific role of insulin-like androgenic gland () hormone in morphotype differentiation of To achieve this, RNAi mediated knockdown as well as augmentation of transcripts were effected in ∼60 g OC males using plasmid-based constructs pcD-IAG-lh and pcD-IAGorf, respectively. The treatments were administered to animals maintained in isolation as well as in community. The knockdown plasmid construct that expresses -specific long hairpin RNA caused 16-fold reduction of transcripts in the SSN1 cell line When injected into OC males living in a community, 2.3-fold knockdown was recorded, while in isolated OC males it was 4.2-fold initially, but returned to normal subsequently. Compared with the respective controls, OC to BC transformations in the silenced animals were significantly lower in the community-reared group, while no difference was observed in the isolated animals. It is reported here for the first time that augmentation in OC males resulted in significantly higher OC to BC transformations, when animals were reared in community. This plasmid-based IAG knockdown approach could be developed into a low stress, feed or immersion treatment for controlling heterogeneous individual growth of males in aquaculture.