Freshwater prawns (Macrobrachium rosenbenii) and some marine shrimp (Penaeus sp) have sexual dimorphism which mandates that sex of these species be managed separately. Monosex and skewed sex ratio progeny groups can be generated from mating sex reversed parental broodstock. The technology to do this could be based upon sex reversal using the androgenic hormone (AH) from the androgenic gland (AG) - an organ responsible for masculinization. When AH or AG is delivered to sexually undifferentiated females they develop into functioning males. The work proposed here focuses on the initial development of a delivery system to sex reverse prawns and shrimp using prawn AG and Iyophilized cell-free extract (LCE). Cross species reactivity is tested using prawn AG implants into marine shrimp. Enteric coat LCE will be delivered to prawn post larvae (PLs) in feed especially developed for the purpose. LCE will also be delivered to the juvenile and ovigerous prawns and shrimp by injection testing dosage levels of 5, 10, and 20 prawn androgenic gland units (PAGUs). Evidence of masculinization will be judged by the appearance of male secondary sex appendage characteristics and initiation of acute degeneration of oocytes.Applications:Results anticipated are that the cell-free extract containing the prawn androgenic gland hormone will cause an acute positive reaction in the female recipient - ovaries will begin to degenerate and male secondary characteristics will appear. Marine shrimp will respond to glandular implants in a similar fashion. Eventual commercial application includes the ability to rear one sex or the other with a 20-309b increase in production.
