Arginine-genotype interactions and immune status

The effects of arginine on selective immune responses were investigated in a high arginine-requiring (HA) and low arginine-requiring (LA) strain of ch ickens. Female chickens from these strains were fed diet containing a nutri tionally inadequate level of arginine (0.53% arginine diet) or a surfeit le vel of arginine (1.53% arginine diet) for 2 weeks. Compared to LA chickens, HA chickens showed a higher feed efficiency, body weight gain, and relativ e thymus and spleen weights with L-arginine supplementation (p < 0,05). In both HA and LA chickens, a deficiency of arginine significantly decreased t he delayed-type hypersensitivity response (p < 0.05) and nitric oxide (NO) production from macrophages, Chickens of the HA strain had higher NO produc tion than those of LA strain with E, coli lipopolysaccharide (LPS) activati on. This study indicates that dietary arginine concentration influences the immune status of chickens and that strains that differ in arginine require ments for growth may differ in their arginine needs for immune function. (C ) 2001 Elsevier Science Inc. All rights reserved.