Beneficial effect of amino acid supplementation, especially cysteine, on body nitrogen economy in septic rats.
OBJECTIVE
Muscle wasting and increased synthesis of proteins and compounds involved in host defense characterize severe injury. The aims of the studies reported were to determine which amino acids exhibited an increased tissue content linked to anabolic processes in infected rats by comparison with healthy pair-fed controls, and to explore whether diets supplemented with these amino acids attenuate the catabolic response to infection.


METHODS
Total amino acid content of the liver and the rest of the body were measured in control well-fed rats, in infected rats and their pair-fed controls 2 days after infection. In the nutritional protocols, infected rats were fed with a diet supplemented with alanine (basal diet), or threonine, serine, aspartate, asparagine and arginine (AA) or AA+cysteine (complete diet).


RESULTS
Infection significantly increased liver total amino acid content by 38% for most amino acids. In contrast, the percentage increase was cysteine 79.3, threonine 45.3, aspartate-asparagine 46.3 and serine 46.5. Whole body without liver content of most amino acids decreased after infection due to the catabolic response, while the content of cysteine increased by 6% (P<0.05) and those of threonine and arginine did not decrease. After infection, animals fed the complete diet lost less weight than animals fed the basal diet (P<0.05). Furthermore, AA plus cysteine supplementation reduced significantly urinary nitrogen excretion and muscle wasting.


CONCLUSIONS
The results provide evidence that diet supplementation with cysteine, threonine, serine, aspartate-asparagine and arginine supports the synthesis of vital proteins to spare body protein catabolism during infection.
Breuillé
Denis
D
Centre de Recherches Nestlé, Vers chez-les-blanc, P.O. Box 44 CH1000, Lausanne 26, Switzerland.
Béchereau
Fabienne
F
Buffière
Caroline
C
Denis
Philippe
P
Pouyet
Corinne
C
Obled
Christiane
C
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D003545:Cysteine / Q000378:metabolism; D019587:Dietary Supplements; D008099:Liver / Q000378:metabolism*; D008297:Male; D009133:Muscular Atrophy / Q000378:metabolism / Q000517:prevention & control*; D009584:Nitrogen / Q000378:metabolism*; D009747:Nutritional Physiological Phenomena; D011488:Protein Deficiency / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D018805:Sepsis / Q000378:metabolism*
D000596:Amino Acids; D003545:Cysteine; D009584:Nitrogen