Effects of dietary cysteine on blood sulfur amino acid, glutathione, and malondialdehyde concentrations in cats.
OBJECTIVE
To determine effects of dietary cysteine on blood sulfur amino acids (SAA), reduced glutathione (GSH), oxidized glutathione (GSSG), and malondialdehyde (MDA) concentrations in cats.


METHODS
12 healthy adult cats.


METHODS
Cats were fed diets with a nominal (0.50 g/100 g dry matter [DM]), moderate (1.00 g/100 g DM), or high (1.50 g/100 g DM) cysteine content in a 3 X 3 Latin square design with blocks of 8 weeks' duration. Venous blood samples were collected after each diet had been fed for 4 and 8 weeks, and a CBC and serum biochemical analyses were performed; poikilocyte, reticulocyte, and Heinz body counts were determined; and MDA, GSH, GSSG, and SAA concentrations were measured.


RESULTS
Blood cysteine and MDA concentrations were not significantly affected by dietary cysteine content. Blood methionine, homocysteine, and GSSG concentrations were significantly increased when cats consumed the high cysteine content diet but not when they consumed the moderate cysteine content diet, compared with concentrations obtained when cats consumed the nominal cysteine content diet. Blood GSH concentrations were significantly increased when cats consumed the moderate or high cysteine content diet.


CONCLUSIONS
Increased dietary cysteine content promotes higher blood methionine, homocysteine, GSH, and GSSG concentrations in healthy cats.


CONCLUSIONS
Supplemental dietary cysteine may be indicated to promote glutathione synthesis and ameliorate adverse effects of oxidative damage induced by disease or drugs.
Fettman
M J
MJ
Department of Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523-1671, USA.
Valerius
K D
KD
Ogilvie
G K
GK
Bedwell
C L
CL
Richardson
K L
KL
Walton
J A
JA
Hamar
D W
DW
D000596:Amino Acids / Q000097:blood*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002415:Cats / Q000097:blood*; D003422:Critical Care; D003545:Cysteine / Q000494:pharmacology*; D019587:Dietary Supplements; D005260:Female; D005978:Glutathione / Q000097:blood*; D008297:Male; D008315:Malondialdehyde / Q000097:blood*; D018384:Oxidative Stress; D013455:Sulfur / Q000097:blood*
D000596:Amino Acids; D008315:Malondialdehyde; D013455:Sulfur; D005978:Glutathione; D003545:Cysteine