TY - JOUR
T1 - Comparative study on the induction of triploidy in tilapias, using cold‐ and heat‐shock techniques
AU - Don, J.
AU - Avtalion, R. R.
PY - 1988/5
Y1 - 1988/5
N2 - Optimal conditions for the induction of triploidy in two different species of tilapia, Oreochromis aureus and Oreachromis niloticus, were determined using either heat‐shock or cold‐shock techniques. These treatments were applied at conditions that were separately determined for each species. Embryos of these two species were found to differ in their response to heat‐shock, but not to cold‐shock treatments. The yield of triploid O. niloticus embryos induced at 40.5°C at the zygotic age of 3‐5 min did not exceed 13%, in contrast to 60% obtained in O. aureus (heat‐shocked at 39.5°C at zygotic age of 3 min). The possibility that the different responses of the two species to heat shock is maternally inherited was supported by the fact that the two‐way F1 hybrids also responded in a similar maternally dominant manner. Although the induction of triploidy using heat shock was possible only within a narrow range of zygotic ages (2.5–3.5 and 3.5–4.5 min for O. aureus and O. niloticus, respectively), the induction of triploidy using cold‐shock treatment (11°C for 60 min) could be achieved within a wider range of zygotic ages (0–15 min). A satisfactory yield of troploids in the two species (50 and 60% in O. niloticus and O. aureus, respectively) was obtained using this technique. The possible interpretation of these results, that triploidy could be induced by interfering at two distinct meiotic cell‐division stages, is discussed. It is concluded that the cold‐shock technique is more advantageous for inducing triploidy in O. niloticus, whereas both cold‐shock and heat‐shock techniques are equally efficient in O. aureus.
AB - Optimal conditions for the induction of triploidy in two different species of tilapia, Oreochromis aureus and Oreachromis niloticus, were determined using either heat‐shock or cold‐shock techniques. These treatments were applied at conditions that were separately determined for each species. Embryos of these two species were found to differ in their response to heat‐shock, but not to cold‐shock treatments. The yield of triploid O. niloticus embryos induced at 40.5°C at the zygotic age of 3‐5 min did not exceed 13%, in contrast to 60% obtained in O. aureus (heat‐shocked at 39.5°C at zygotic age of 3 min). The possibility that the different responses of the two species to heat shock is maternally inherited was supported by the fact that the two‐way F1 hybrids also responded in a similar maternally dominant manner. Although the induction of triploidy using heat shock was possible only within a narrow range of zygotic ages (2.5–3.5 and 3.5–4.5 min for O. aureus and O. niloticus, respectively), the induction of triploidy using cold‐shock treatment (11°C for 60 min) could be achieved within a wider range of zygotic ages (0–15 min). A satisfactory yield of troploids in the two species (50 and 60% in O. niloticus and O. aureus, respectively) was obtained using this technique. The possible interpretation of these results, that triploidy could be induced by interfering at two distinct meiotic cell‐division stages, is discussed. It is concluded that the cold‐shock technique is more advantageous for inducing triploidy in O. niloticus, whereas both cold‐shock and heat‐shock techniques are equally efficient in O. aureus.
UR - http://www.scopus.com/inward/record.url?scp=38249027702&partnerID=8YFLogxK
U2 - 10.1111/j.1095-8649.1988.tb05406.x
DO - 10.1111/j.1095-8649.1988.tb05406.x
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SN - 0022-1112
VL - 32
SP - 665
EP - 672
JO - Journal of Fish Biology
JF - Journal of Fish Biology
IS - 5
ER -