Avalia o da arginina dietética sobre a resposta imunológica de frangos de corte imunizados contra a Doen a de Gumboro = Assessment of arginine diet on the immune response of broilers immunized against Gumboro disease

O estudo foi realizado com o objetivo de avaliar o efeito da suplementa o de Arginina (Arg) sobre a resposta imune humoral e o desenvolvimento dos órg os linfoides de frangos de corte imunizados contra a Doen a de Gumboro. Foram utilizados 640 pintos de corte, distribuídos aleatoriamente em um delineamento inteiramente casualizado com quatro tratamentos (1. Controle, 2. Imuniza o, 3. Imuniza o + suplementa o de L-Arg e 4. Suplementa o de L-Arg.) e oito repeti es de 20 aves cada. As aves dos tratamentos 3 e 4foram imunizadas no 16o dia, contra a Doen a de Gumboro (cepa intermediária plus). Amostras de soro das aves com 14, 21, 28 e 35 dias de idade foram analisadas por ELISA para detec o de título de anticorpos contra a Doen a de Gumboro e nestas mesmas idades foi determinado o peso dos órg os linfoides e a altura de pregas primárias do tecido linfoide da bolsa cloacal. N o houve diferen a significativa (p > 0,05) entre os tratamentos. A suplementa o de Arg n o contribuiu com a resposta imune dos frangos de corte imunizados contra a Doen a de Gumboro. A falta de resposta à imuniza o pode seratribuída à baixa virulência da cepa vacinal utilizada e à presen a de vírus de campo. The study was conducted to evaluate the effect of supplemental Arginine (Arg) on the humoral immune response and development oflymphoid organs of broiler chickens vaccinated against Gumboro disease. Six hundred and forty broilers were reared in a complete randomized design with four treatments (1. Control, 2. Immunization, 3. Immunization and supplementation of L-Arg, and 4. Supplemental L-Arg.) and eight replications of 20 birds each. Birds in treatments 3 and 4 were vaccinated at 16 days against Gumboro disease (intermediate plus strain). Serum samples from birds at 14, 21, 28 and 35 days old were analyzed by ELISA for detection of antibody titers against Gumboro disease, and at these same ages, lymphoid organ weight was determined and the height of the primary folds of lymphoid tissue in the cloacal bursa was measured. There was no significant difference (p > 0.05) among treatments. Arg supplementation did not improve the immune response of broilers immunized against Gumboro Disease. The lack of response to immunization may be attributed to the low virulence of the vaccine strain used and the presence of environmental virus.