Genetic parameters of Gill-associated virus infection and body weight under commercial conditions in black tiger shrimp, Penaeus monodon

Selective breeding to improve performance of growth and increase disease resistance is becoming commonplace within shrimp aquaculture. Whilst estimated breeding values (EBV) for growth can be evaluated easily in on-farm trials, EBVs for disease resistance are usually obtained from controlled laboratory challenges and may not be indicative of natural infection and resistance in a commercial setting. If they are not the same trait, this will result in a low genetic correlation between the traits and application of EBVs derived from the laboratory challenge will lead to overall slow genetic progress for improved disease resistance in on-farm conditions. There is a need for alternative measures of predicting disease resistance based on performance in farm environments. Two such estimates may be viral infection status (presence/absence) and load of farm reared shrimp.