Distinct physiological, plasma amino acid, and liver transcriptome responses to purified dietary beef, chicken, fish, and pork proteins in young rats

Young rats received semi-synthetic diets for 1 wk that differed only<br/>regarding protein source; casein (reference) was replaced by beef, chicken, fish, or pork proteins.<br/>Compared to casein, all proteins, except pork, increased total plasma AA concentrations.<br/>Pork protein reduced adipose tissue mass and liver triacylglycerol, which was accompanied<br/>by increased plasma triacylglycerol concentrations. Plasma cholesterol was reduced by fish<br/>protein. The number of differentially expressed genes ranged between 609 (pork) and 1258<br/>(chicken); on average one-third of the changes were specific for each meat protein. Pathway<br/>responses were most similar for beef and chicken, followed by pork and fish. Although the<br/>extent varied, allmeat proteins inducedmRNAtranslation, antigen processing/presentation, intracellular<br/>vesicular trafficking, and oxidoreductive-transformation pathways, and suppressed<br/>signal-transduction (Notch, TGFB/SMAD, insulin) and mitochondrial biogenesis pathways.<br/>Lipid- and AA-metabolic pathways were repressed, except by pork. AA-transport pathways were<br/>induced by beef and fish only, and complement/coagulation-pathways were suppressed by<br/>chicken and beef. Fish suppressed nuclear-transport and cofactor metabolism.<br/>Conclusion: To conclude, short-term feeding of different meat proteins resulted in distinc