Incidence of conjoined twins in tilapia after thermal shock induction of polyploidy
Article first published online: 24 DEC 2001
Volume 31, Issue 5, pages 421–426, May 2000
How to Cite
Owusu-Frimpong, M. and Hargreaves, J. A. (2000), Incidence of conjoined twins in tilapia after thermal shock induction of polyploidy. Aquaculture Research, 31: 421–426. doi: 10.1046/j.1365-2109.2000.00440.x
- Issue published online: 24 DEC 2001
- Article first published online: 24 DEC 2001
Conjoined twins (polyembryonic fish) were observed in batches of blue tilapia Oreochromis aureus (Steindachner) and Nile tilapia O. niloticus (L.) embryos incubated at 28 °C. Heat shock (41.8 °C) treatment of fertilized eggs for 3–4 min applied between 4 min and 27 min after fertilization increased the twinning rate by three or four times over that of unshocked eggs. Two basic morphological variations – ventrally or laterally conjoined twins – were observed. Twins did not survive beyond 21 days after hatching. The proportion of twins in heat-shocked egg batches of both species combined ranged from 0.32% to 0.40%.