SECTION A: NEW WORK PLANS

THAILAND RESEARCH

Collaborating Institutions
Asian Institute of Technology
Amrit Bart

The University of Michigan—Lead US Institution
James S. Diana
C. Kwei Lin
Yang Yi

Objectives
1) To examine the efficacy of using ultrasound technology to enhance the delivery of androgens with slight modification of the immersion techniques proposed in the Ninth Work Plan; and
2) Assess the amount of methyltestosterone (MT) residue in a commercial tilapia hatchery in Thailand using standard RIA or HPLC protocol.

Significance
Control of reproduction is one of the priority areas of the PD/A CRSP Continuation Plan 1996—2001.Reproduction control of tilapia is critical to the success of most forms of production because tilapia have such high reproductive capacity. Various management practices have been used to control reproduction and produce all-male populations, including use of hormones, selective breeding, and androgenetic techniques. In the Eighth Work Plan, studies were initiated to develop methods for inducing androgenesis in tilapia. In the Ninth Work Plan, studies are proposed to continue development of androgenetic techniques–namely the use of irradiation protocols. This investigation will use ultrasound technology to enhance the delivery of androgens. Past CRSP research has already identified appropriate methods for the delivery of androgens such as methyltestosterone, trenbolone acetate, and methyldihydrotestosterone.

Experimental Design
Masculinization
1) Test three different androgens (trenbolone acetate, methyldihydrotestosterone, and methyltestosterone) and their ability to masculinize tilapia using an immersion protocol.
2) Based on the findings of the above protocol, use cavitation-level ultrasound to enhance delivery at various doses and at different duration of treatments.

Schedule
Detailed preparation of protocol: September—November 1999
Experimental period: January—May 2000
Analysis: June—August 2000
Preparation of final report and manuscripts: September—October 2000