Genetic parameter estimates
for reproductive traits and egg composition in Pacific white shrimp Penaeus
(Litopenaeus) vannamei
F.G. Arcos, I.S. Racotta, A.M. Ibarra-2004
Aquaculture, 236(1-4): 151-165
Abstract:
We estimated the heritabilities and genetic
correlations for reproductive traits and egg composition in female shrimp, Penaeus
(Litopenaeus) vannamei. The traits under analysis were days to first
spawn after ablation (DTFS), egg diameter (ED) and number (EN), and egg
triacylglycerides (TG), vitellin (VIT), total protein (PROT) and total
lipids (LIP) for first spawned eggs. Estimates were based on 1–11 females
from 30 full-sib families produced in 2000 and derived from the so-called
‘Melagos’ line in Mexico. Heritabilities were estimated using REML
procedures from data on females that spawned at least once (56%). For ED,
EN, and VIT, TG, PROT, and LIP in eggs, a square root transformation was
done to normalize the data. Data was analysed using two models, one did not
include any other trait as covariate, and the other included other trait as
covariate. For DTFS the total number of spawns/female was used as covariate.
For VIT, TG, PROT, and LIP in eggs the covariate used was egg number in that
spawn. For egg number and egg diameter the other variable was reciprocally
used as covariate. Heritabilities estimated without covariates were 0.41 for
DTFS, 0.09 for EN, 0 for ED, 0.28 for VIT, 0.20 for TG, 0.13 for PROT, and 0
for LIP. Heritabilities for all traits but lipids increased when the
covariates were introduced in the estimation of variance components; 0.54
for DTFS, 0.17 for EN, 0.07 for ED, 0.47 for VIT, and 0.35 for TG, 0.18 for
PROT, and 0 for LIP. Despite large standard errors caused by small effective
sample size, the estimates of the heritabilities indicate that these traits
can be subjected to selection to improve reproductive output from females.
(Programa de Acuacultura, Centro de Investigaciones
Biológicas del Noroeste (CIBNOR), Mar Bermejo 195, AP 128., La Paz B.S.,
23090, Mexico, e-mail of A.M. Ibarra: aibarra@cibnor.mx)