The use of the hormone 17α methyltestosterone in tilapia

Editor/ Mohamed Shihab

Impacts of the use of the hormone 17α methyltestosterone in tilapia farming (Oreochromis niloticus L.1758) on market sized fish and the environment

Authors:

 Khalifa Babacar Sylla, Marie Louise Senghor, Hamet Diaw Disdhiou, Waly Ndiaye and Massal Fall

FAO

AFRICAN NETWORK ON FISH TECHNOLOGY AND SAFETY 2021 Book of abstracts 6–9 December 2021

Abstract 9:

The study was designed to analyse the fate of the hormone 17α methyltestosterone in the flesh and in the rearing water of tilapia (Oreochromis niloticus), treated for 28 days with different doses of the hormone (30, 60 and 90 mg methyltestosterone per kg feed), followed by a five month grow-out phase. On the sixtieth day post-treatment, the percentage of males was evaluated in each batch and the flesh and water samples were analysed. It emerged from the results that the means of the sex ratio in the different treated batches were 98 percent, 100 percent and 96 percent of males respectively with the doses of 30, 60 and 90 mg methyltestosterone per kg of feed, as compared with the batch of untreated tilapia having 52 percent males and 48 percent females. As for hormone residues in the flesh and water of rearing fish, the concentrations of methyltestosterone in the flesh were very high after the first sample collection. But these concentrations decreased with significant differences and fell below the detection threshold after 60 days post-treatment. Methyltestosterone concentrations in the water samples were below the detection limit (1.3 µg per millilitre) and were considered insignificant.