Aquaculture, 114 (1993) 33-40 Elsevier Science Publishers B.V.,
Arnsterdam Physiological factors affecting triploid production in rainbow trout, Oncorhynchus
N.F. Diaz1, P. Iturra2 , A. Veloso1, F. Estay1 and N. Colihueque1
1.- Facultad de Ciencias, Casilla 653, and
2.- Facultad de Medicina, Universidad de Chile, Santiago, Chile
(Accepted 25 February 1993)
The influence of three physiological factors related to triploid production was examined for rainbow trout. Individual spawnings of 46 females were used to perform triploid production experiments
from 1989 to 1991, with various water temperaturas (6-13.8ºC) at stripping and egg incubation. The percentage of triploids was similar for a heat shock of 26.5ºC for 15 min applied 15 or 25 min
after fertilization (73.4 ± 5.6% vs 78.6 ± 4.5%). A tendency to a higher percentage of triploids (85.9 ± 5.7%) was observed for water temperaturas of 6-8.0ºC at stripping and incubation, compared
to at higher water temperaturas of 12.1-14ºC (63.0 ± 8.4%). Analysis of variance indicated an effect of four categories of water temperatura (6-8, 8.1-10, 10.1-12, 12.1-14ºC) on triploid product
at P= 0.14. Regression analysis confirmed these as significant (r= -0.36; P< 0.02). A significan increase in percentage of triploids was observed when eggs remained 2, 6 and 10 days in the
body cavity. The mean % triploidy was 46.1, 54.7 and 76.8, respectively. Similar results were observed for survival of the eggs.
*Supported by FONDECYT 1043/90 Grant.