Quantitative genetics of taura syndrome resistance in pacific white shrimp (penaeus vannamei): a cure model approach

Genetics Selection Evolution

Research

Per Madsen¹  M Hossein Yazdi²  Morten Rye²  Thomas Gitterle³  Carlos Pulgarin⁴  Jørgen Ødegård⁵  Bjarne Gjerde⁵  Theo HE Meuwissen⁶ 

[1] Aarhus University, DK-8830, Tjele, Denmark;Akvaforsk Genetics Center AS, NO-6600, Sunndalsøra, Norway;Akvaforsk Genetics Center AS, NO-6600, Sunndalsøra, Norway;CENIACUA, Bogotá, Colombia;CENIACUA, Bogotá, Colombia;Nofima Marin, NO-1432, Ås, Norway;Norwegian University of Life Sciences, NO-1432, Ås, Norway;Norwegian University of Life Sciences, NO-1432, Ås, Norway;

关键词: Genetic Correlation;    Genetic Evaluation;    Susceptibility Status;    Pacific White Shrimp;    Survival Score;   

DOI  :  10.1186/1297-9686-43-14

 received in 2010-12-13, accepted in 2011-03-21,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundIn aquaculture breeding, resistance against infectious diseases is commonly assessed as time until death under exposure to a pathogen. For some diseases, a fraction of the individuals may appear as "cured" (non-susceptible), and the resulting survival time may thus be a result of two confounded underlying traits, i.e., endurance (individual hazard) and susceptibility (whether at risk or not), which may be accounted for by fitting a cure survival model. We applied a cure model to survival data of Pacific white shrimp (Penaeus vannamei) challenged with the Taura syndrome virus, which is one of the major pathogens of Panaeid shrimp species.MethodsIn total, 15,261 individuals of 513 full-sib families from three generations were challenge-tested in 21 separate tests (tanks). All challenge-tests were run until mortality naturally ceased. Time-until-event data were analyzed with a mixed cure survival model using Gibbs sampling, treating susceptibility and endurance as separate genetic traits.ResultsOverall mortality at the end of test was 28%, while 38% of the population was considered susceptible to the disease. The estimated underlying heritability was high for susceptibility (0.41 ± 0.07), but low for endurance (0.07 ± 0.03). Furthermore, endurance and susceptibility were distinct genetic traits (rg = 0.22 ± 0.25). Estimated breeding values for endurance and susceptibility were only moderately correlated (0.50), while estimated breeding values from classical models for analysis of challenge-test survival (ignoring the cured fraction) were closely correlated with estimated breeding values for susceptibility, but less correlated with estimated breeding values for endurance.ConclusionsFor Taura syndrome resistance, endurance and susceptibility are apparently distinct genetic traits. However, genetic evaluation of susceptibility based on the cure model showed clear associations with standard genetic evaluations that ignore the cure fraction for these data. Using the current testing design, genetic variation in observed survival time and absolute survival at the end of test were most likely dominated by genetic variation in susceptibility. If the aim is to reduce susceptibility, earlier termination of the challenge-test or back-truncation of the follow-up period should be avoided, as this may shift focus of selection towards endurance rather than susceptibility.

【 授权许可】

CC BY   
© Ødegård et al; licensee BioMed Central Ltd. 2011