Wistar Kyoto (WKY) rats, an animal depression model, display abnormal behaviorssuch as hypoactivity and depression-like behavior compared with Wistar (WIS) rats as a control.A previous study confirmed a dysfunction of amino acid metabolism in the brain of WKY ratscompared with that of WIS rats. At the neonatal stage, free amino acids in milk are importantnutrients because they act as immediate nutrients for offspring and may affect later health andbehavior of the offspring. Therefore, the present study aimed to investigate free amino acidconcentrations in milk and the relationships between free amino acid concentrations in milk andplasma in WIS and WKY rats. The concentrations of ten of the determined free amino acids in milkwere significantly higher, but only L-methionine was significantly lower, in WKY rats. Six free aminoacids had significantly higher concentrations in colostrum and two free amino acids had higherconcentrations in matured milk. Free amino acid concentrations in plasma changed by bothgenetic background and lactation stage; however, the patterns of change in most free amino acidconcentrations except for taurine in plasma were similar between WIS and WKY rats. The transportratio of free amino acids from plasma to milk was not similar among the free amino acids tested,and each free amino acid was influenced by the genetic background and/or the type of milk.
All Science Journal Classification (ASJC) codes