Induction of triploidy and tetraploidy in Nile tilapia, Oreochromis niloticus (L.)

• Published in: Journal of the World Aquaculture Society Vol. 30; no. 2; pp. 269 - 275
• Main Authors: El Gamal, A.A, Davis, K.B, Jenkins, J.A, Les Torrans, E
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.06.1999
• Subjects: animal breeding; cold stress; cytochalasin a; cytochalasin B; fertilization (reproduction); fish culture; Freshwater; heat stress; metabolic inhibitors; Oreochromis niloticus; pressure; tetraploidy; triploidy; water temperature
• ISSN: 0893-8849; 1749-7345
• DOI: 10.1111/j.1749-7345.1999.tb00875.x

.— Induction of triploidy and tetraploidy in Nile tilapia, Oreochromis niloticus, was investigated by heat shock, cold shock, hydrostatic pressure, and/or chemicals (cytochalasin A, B, and D). Additionally, efficacy of combined protocols was determined. Heat shock 10 min after fertilization induced triploidy when incubation temperature was 24 C but not when incubation temperature was 31 C. Heat shock of 40–41 C at 4–6 min after fertilization was effective in inducing up to 100% triploidy with hatchability similar to controls. Cold shock at 13 C for 45 min five min after fertilization induced 85–100% triploids. Heat shock and multiple heat shocking were the most effective treatments for the induction of tetraploidy. Two heat treatments of 41 C applied at 65 and 80 min after fertilization for 5 min each produced approximately 80% tetraploidy in hatched fry. Immersion of fertilized eggs in cytochalasin A, B, or D at concentrations up to 10 μg/L applied at various times and durations was ineffective in inducing triploidy or tetraploidy.