Fillet quality and gene transcriptome profiling of heart tissue of Atlantic salmon with pancreas disease (PD)

Abstract

Pancreas disease (PD) caused by salmonid alphavirus (SAV) results in heavy economical losses for Atlantic salmon (Salmo salar L.) farms in Norway, largely due to mortality, poor performance of fish and deteriorated fillet quality. This study determined the fillet quality and heart gene transcriptome in farmed Atlantic salmon (2.2kg gutted weight) with varying PD pathology at slaughter: group A, SAV negative and PD negative; group B, SAV positive and PD negative; group C, SAV positive and PD positive. Gene expression and fillet quality characteristics of groups A and B were similar. Fish of group C had a thin body shape and pale and abnormally firm fillets with high collagen and low protein content, as well as an altered amino acid and fatty acid profile. They also had a marked reduction of energy metabolism and cell proliferation according to gene expression analyses. It is concluded that salmon infected with PD virus (SAV) may have acceptable fillet quality, but loss of pancreatic tissue may result in poor nutritional status of heart and muscle and unacceptable fillet quality. Hence such fish should not progress toward the market chain.