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

A.-R.A. El Gamal·K. B. Davis·J.A. Jenkins·Torrans E. Les
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Abstract

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.

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A.-R.A. El Gamal, K. B. Davis, J.A. Jenkins, Torrans E. Les. 2007-04-03. Induction of triploidy and tetraploidy in Nile tilapia, Oreochromis niloticus (L.). https://doi.org/10.1111/j.1749-7345.1999.tb00875.x

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