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The uses of breeding programs for the Pacific white shrimp [Penaeus (Litopenaeus) vannamei] based on mixed linear models with pedigreed data are described. The application of these classic breeding methods yielded continuous progress of great value to increase the profitability of the shrimp industry in several countries. Recent advances in such areas as genomics in shrimp will allow for the development of new breeding programs in the near future that will increase genetic progress. In particular, these novel techniques may help increase disease resistance to specific emerging diseases, which is today a very important component of shrimp breeding programs. Thanks to increased selection accuracy, simulated genetic advance using genomic selection for survival to a disease challenge was up to 2.6 times that of phenotypic sib selection.

Real and simulated data sets were analysed to estimate the effect of data structure (i.e. the number of dams mated to one sire and the number of tanks per dam) and the model used for analysis on the bias of genetic parameter estimates of the square root of 28-day body weight (BW28) in Penaeus vannamei. Estimated parameters used were 0.13 for the heritability (h 2 ); 0.16 for the proportion of the variance of the maternal and common environmental effects (c 2 ); 0.15 for the proportion of the tank effect variance (t 2 ) and 0.56 for the proportion of the environmental variance (e 2 ). Total variance for the BW28 was 2.36 mg. Simulated data involved a total of 9000 sires and 1 444 000 offspring. Exclusion of maternal and common environmental effects inflated estimates of heritability both in real and simulated data. Exclusion of tank effects from the model inflated the estimates of heritability in real, but not in simulated data, indicating the presence of non-random effects affecting individual tanks. We conclude that replication of dams per sire is necessary for obtaining unbiased estimates of heritability. Use of replicated tanks may help in reducing overestimation of heritability if tank and genetic effects are confounded.

The aim of this study was to estimate genetic parameters for spawning traits and growth traits in a breeding line of Pacific white shrimp, Penaeus (Litopenaeus) vannamei, selected for growth and survival. Traits studied were number of eggs (NE) and number of nauplii (NN) and female body weight at insemination (FWI) and body weight at 130 days of age (BW130). Genetic parameters were estimated using a multivariate animal model. Heritability for NE and NN were estimated as 0.13 ± 0.04 and 0.03 ± 0.04 respectively. The contribution to NN total variation due to ‘factors associated with male’ effect was estimated as 0.47 ± 0.07. In the cases of FWI and BW130, heritability was estimated as 0.44 ± 0.08 and 0.19 ± 0.03 respectively. Genetic correlation between FWI and NE was estimated as 0.49 ± 0.15, between FWI and NN as 0.54 ± 0.39 and between NE and NN as 0.27 ± 0.41, whereas the genetic correlations of FWI, NE and NN with BW130 were 0.30 ± 0.13, −0.21 ± 0.19 and −0.25 ± 0.38 respectively. Although it is important to perform more studies on this issue, our results found no evidence of a genetic antagonistic effect between female reproductive traits and body weight at harvesting (130 days of age) in P. vannamei.

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