Masculinization of Tilapia by Immersion in Trenbolone Acetate:detection of Trenbolone Acetate in Water after Treatment

In a previous experiment in which Nile tilapia fry were successfully masculinized, we investigated how the concentration of trenbolone acetate (TA) in the immersion water changed before and after treatment. The results from that experiment indicated that the concentration of TA before and after treatment of Nile tilapia fry was highly variable and below the expected levels. Therefore, we decided to corroborate those results by running two experiments in which fry were not present and by testing different water sources. These new experiments confirmed our previous findings, indicating that independently of the source of water, the concentration of TA is highly variable and below the expected levels. NINETEENTH ANNUAL TECHNICAL REPORT 32 by vortexing. Samples of 1 ml were collected at time 0 (from the middle of the tube) and at 1 h (from the surface, middle, and bottom). Once all samples were collected, the water remaining in the tube was vortexed, and the tube was emptied and washed with 1 ml of ether to assay for TA attached to the tube walls.