Manipulating dietary protein and amino acids in the common marmoset Callithrix jacchus impacts circulating metabolites and FGF21 levels

Restricting dietary protein intake has metabolic and physiological benefits for animals. Rodent studies have identified the involvement of a hormone, fibroblast growth factor 21 (FGF21), which is upregulated by sensing amino acid scarcity. However, to what extent this mechanism is conserved in primates remains elusive. Using common marmosets, Callithrix jacchus, as a non-human primate model, we develop a protocol for protein restriction and dietary amino acid manipulation. Low protein diet induces a decrease in blood urea nitrogen, altered plasma amino acid profiles, and an increase in plasma FGF21. Supplementation of purified amino acids to the diet suppresses plasma features of protein restriction. Our study provides a dietary intervention technique in marmosets and an insight into the evolutionarily conserved mechanism of FGF21 induction during protein restriction.