GENETIC (CO)VARIANCES IN ACUTE HEPATOPANCREATIC NECROSIS DISEASE (AHPND) RESISTANCE, HARVEST WEIGHT AND SURVIVAL IN Penaeus vannamei

Thomas Gitterle*, Tanatchaporn Utairungsee*, Chotitat Luengchaichawange and Daniel Fegan
SyAqua Siam Co.,
 

Diseases are a major constraint on the intensive production of shrimps. Conditions in production ponds favor disease development, and epidemics of several previously unreported diseases have occurred and caused severe losses. When elimination, eradication or cultural control is difficult, selective breeding for host resistance to the pathogen may be an attractive option for disease control.   

Commercial growers now seed ponds with shrimp populations selected for resistance to Taura Syndrome Virus with excellent results, whilst up to now development of White Spot Syndrome Virus resistant populations has been an elusive goal when selection is made on family means.

Despite, AHPND has been one of the major threats for the shrimp industry, there is no information on the possibility of applying selecting breeding as a measure to control the epidemic nor the effect over other important economic traits like growth and pond survival.

In this paper we present the first results of the genetic (co)variation in resistance to AHPND, harvest weight (HW) and pond survival (S).

To assess the genetic resistance to AHPND 95 families from SyAquas breeding program were challenged by two different methodologies: a) direct infection with the bacteria and (Bac) and b) using an isolate of the AHPND toxin (Tox).

Results indicate substantial additive genetic variation for all traits with a favorable and moderate genetic correlation between the two AHPND infection methods and between Harvest weight and Pond Survival. (Table 1). Genetic correlations between AHPND resistance and harvest weight and pond survival were not significant different from cero.

Based on these findings we conclude that it is possible to select for AHPND resistance with no effect over other important economic traits and that the toxin might be used as a proxy of bacterial infection.