Changes in cerebrospinal fluid and plasma amino acid concentrations with elevated dietary protein concentration in dogs with portacaval shunts

Effects of dietary protein concentration on plasma and cerebrospinal fluid (CSF) amino acids (AA) in dogs with portacaval shunts (PCS) were examined. An 18% protein purified diet (18P) was fed to 4 PCS dogs and 2 controls; at week 10, 2 of the PCS dogs were switched to 36% protein (36P) until week 28. Effects of the diet switch on plasma and CSF AA in 8 normal dogs were determined in another experiment. Neither surgery nor protein level significantly affected average food intake (weeks 10–28). Plasma amino acid patterns typical of PCS animals were observed: phenylalanine and tyrosine increased and branched chain AA decreased with shunting (p