Genetic analysis of Rous sarcoma virus (subgroup A) induced tumourigenesis and performance of synthetic broiler stocks in relation to group-specific antigen shedding

Abstract

An investigation was made using two high-performance meat lines, synthetic male line (SML) and synthetic dam line (SDL), to assess the susceptibility pattern in response to subgroup A Rous sarcoma virus (RSV) and the effect of group-specific (gs) antigen shedding in eggs, as evidence of avian leukosis virus infection effects on production and fitness traits. The ar gene frequency was observed to be at 0.68 +/- 0.04 and 0.66 +/- 0.06 for SDL and SML lines, respectively. Synthetic broiler lines were fivefold less sensitive to pock expression in chorioallantoic membranes (CAMs) as compared with a White Leghorn (WL-2A) reference line, in response to Bryan standard RSV (subgroup A). It was also observed that gs antigen shedding had neither influence on pock response in CAMs nor on induced liver tumour death. The prevalence of gs antigen shedding, however, fluctuated from generation to generation, ranging from 16.66 to 69.23% in SDL and 20.68 to 51.85% in SML, indicating an exogenous infection. Analysis of the relationship of gs antigen shedding in eggs with some fitness traits and overall flock production traits provided strong evidence that fitness traits such as fertility, hatchability, and production traits, such as 6-week body weight and egg weight, were significantly influenced by gs shedding.