Dietary DNA in blood and organs of Atlantic salmon (Salmo salar L.)

The objective of this study was to investigate the uptake of dietary DNA into blood, kidney, and liver of salmon, and to determine the DNA fragment size if dietary DNA was detected. Salmon in groups of five fish were force-fed a feed containing a high copy number of three polymerase chain reaction (PCR) amplified DNA fragments. Tissue samples were dissected from the fish at time intervals starting at 1 h after force-feeding (AFF) and ending at 64 h AFF. Real-time PCR analyses were used to determine the presence or absence of DNA targets. Sensitive methods amplifying small fragments were used to minimise the impact of fragmentation on the detectability of DNA targets. Uptake of dietary DNA was observed and the highest concentrations of dietary DNA in liver and kidney were found 8 h AFF. The results correspond to data published for similar trials performed on other animal species. An additional experiment showed that decontamination of the liver surface by flaming has the potential to decrease DNA contamination from, for example, feed remnants by up to 90%.