Postprandial effects of protein from salmon by-products and whey on gene expression in liver cells.

Exploring the metabolic effects of fish protein is important, as by-products from fish contain large amounts of proteins that could be used for human consumption. The aim of this study was to investigate the postprandial effects of intake of protein from salmon by-products, compared to whey. As part of this effort, the effects on gene expression in liver cells were studied in vitro. This was done by incubating HepG2 cells with human serum taken before (fasting) or 30 and 60 min after intake of salmon protein or whey and comparing that with HepG2 cells incubated in serum-free medium. Transcriptomic profiling of the cells was done with RNA sequencing. Overall design: In a randomised controlled, cross-over trial, five healthy male participants consumed 5.2 grams of protein from either salmon fishmeal or whey. Blood samples were taken before (fasting), and 30 and 60 min after intake. To investigate the postprandial effects of fishmeal or whey on hepatic gene expression, cultured HepG2 cells were incubated for 6 hours with or without serum from the cross-over trial, and transcriptomic profiling performed by RNA sequencing. Total RNA from HepG2 cells incubated with serum from all five participant [before (n=5; fasting), and 30 min (n=5) and 60 min after (n=5) intake of both fishmeal and whey], as well as RNA from six serum-free HepG2 cultures - 36 samples in total - was sequenced.