Induction of triploidy with caffeine treatment in the African catfish (Clarias gariepinus)

Induction of triploidy is one of the biotechnological methods in aquaculture used for genetic manipulation. It refers to a state where organisms have three complete sets of chromosomes instead of two and can result in sterility. Caffeine treatment that is safe and inexpensive, serve to induce triploidy in catfish. To suppress the second meiotic division, fertilized eggs were exposed to three different concentrations (5, 10 and 15 mM) of caffeine solution for 20 min beginning at 3 min after fertilization. After that, the eggs were incubated at ambient temperature until hatching. The induction of triploidy in fry was determined for three concentrations of caffeine by means of flow-cytometric analysis. The lowest rate of triploidy (20.40 ± 1.13%) was obtained in the group treated with 5 mM caffeine and the highest (69.10 ± 2.18%) in the group treated with 15 mM caffeine. Our results suggest that caffeine can be used to induce triploidy in catfish.