Genetic (co)variation for resistance to white spot syndrome virus, acute hepatopancreatic necrosis, and overall pond survival in Litopenaeus vannamei

This study aimed to assess the genetic parameters associated with survival against acute hepatopancreatic necrosis (S_AHPND) and white spot syndrome virus (S_WSSV) in controlled challenge settings, as well as survival in commercial ponds (S_COMERCIAL) and within a high biosecurity genetic nucleus (S_NUCLEUS). Two lines were studied: one with a history of resistance to WSSV (RES) and another focused on rapid growth but susceptible to WSSV (GRO). All traits were analyzed as binary (alive or dead), and (co)variance components were estimated using a within-line multivariate linear animal model. Heritabilities for S_AHPND and S_WSSV ranged from 0.09 to 0.15 and from 0.01 to 0.14, respectively. In the case of S_COMMERCIAL, heritabilities spanned from 0.01 to 0.23, and for S_NUCLEUS, they were between 0.02 and 0.08. Notably, genetic correlations (r(g)) between S_WSSV and S_AHPND exceeded 0.50 in both lines. When examining S_COMMERCIAL, r(g) with S_AHPND in GRO were estimated at values between 0.25 and 0.51, while in RES, they ranged from 0.23 to 0.62. Regarding S_WSSV, r(g) ranged from - 0.04 to 0.60 in GRO and from 0.22 to 0.76 in RES. The r(g) between S_NUCLEUS and the other traits fell within the range of - 0.15 to 0.74. Spearman correlations between the family breeding values for all four traits were estimated to be between 0.31 and 0.66. In summary, this study found that additive genetic variation for these traits ranged from low to moderate. The results suggest the potential for a correlated response in overall commercial survival (S_COMERCIAL) when selecting for improved specific-pathogen resistance against both S_AHPND and S_WSSV.