ABSTRACT This study was performed to evaluate the effects of the association of different digestible arginine and phytogenic additive dietary levels on performance and health status of brown-egg layers. In this study, a total of 504 33-week-old Hisex Brown layers were distributed into a completely randomized experimental design to a 4 × 3 factorial arrangement (dietary digestible arginine levels: 880, 968, 1056, or 1144 mg/kg of feed × phytogenic additive levels: 0, 100, and 200 mg/kg of feed) with six replicate cages of seven birds per cage. The phytogenic additive was composed of extracts of Baccharis dracunculifolia (40%), Astragalus membranaceus lipopolysaccharides (20%), cinnamon, and grape seed (20%). Feed intake was reduced when diets containing 1056 mg of arginine were supplemented with 100 or 200 mg phytogenic additive per kg. Feed conversion ratio was improved when diets were supplemented with 100 mg of phytogenic additive or with 1056 mg of arginine per kg of feed. Egg mass was increased when diets were supplemented with 1056 mg arginine per kg of feed. Arginine supplementation quadratically increased albumen percentage and reduced yolk percentage. Higher arginine and phytogenic additive levels reduced heterophyl:lymphocyte ratio and blood uric acid, total cholesterol, very-low density lipoprotein, and triglyceride levels. Dietary supplementation of 100 mg of phytogenic additive associated with high arginine levels increased nitric oxide production by peritoneal macrophages and 1056 mg of arginine increased antibodies titers against Newcastle disease virus. Blood and intestinal malonaldehyde levels were reduced when 200 mg of the phytogenic additive was added. Dietary supplementation of 968 mg of arginine or 100 mg of a phytogenic additive (40% Baccharis dracunculifolia, 20% Astragalus membranaceus, 20% cinnamon, and 20% grape seed extracts) per kilogram of diet improves the feed conversion ratio and associated inclusion of 1144 mg of arginine and 100 mg of phytogenic additive per kilogram of diet improves immune responses and health status of brown-egg layers.

RESUMO. Avaliou-se o efeito da inclusão de complexos enzimáticos (CE1 e CE2) em dietas com níveis reduzidos sobre desempenho e viabilidade econômica de frangos. Foram utilizados 840 pintos, distribuídos em delineamento inteiramente casualizado com sete tratamentos e quatro repetições: 1) controle positivo (CP), dieta formulada para atender às exigências nutricionais; 2) controle negativo 1 (CN1), dieta com níveis nutricionais reduzidos; 3) CN1+CE1; 4) CN2: dieta com proteína e aminoácidos do farelo de soja valorizados em 7%; 5) CN2+CE2; 6) CN3: dieta com níveis reduzidos, e farelo de soja valorizado em 7% para proteína e aminoácidos; 7) CN3+CE1+CE2. A conversão alimentar foi maior em aves que receberam dietas CN1 ou CN3 aos sete, 21 e 42 dias, e CN2 aos 21 dias. A inclusão de CE2 na dieta CN2 melhorou a conversão alimentar em relação a CN2, tornando-a semelhante à de aves alimentadas com dieta CP aos 21 dias. A associação de CE1+CE2 na dieta CN3 não favoreceu o desempenho. Portanto, o uso de complexo enzimático (CE2) em dieta com níveis reduzidos mantém a conversão alimentar similar à de aves recebendo dieta-padrão no período de um a 21 dias, porém, no período de um a 42 dias, não melhora o desempenho de frangos.

ABSTRACT. This study evaluated the effect of multienzyme complexes (EC1 and EC2) in low nutritional density diets on performance and economic viability of broilers. A total of 840 day-old chicks were assigned to 7 treatments, distributed in a completely randomized design: (1) PC: positive control, basal diet formulated to meet nutritional requirements; (2) NC1: negative control, reduced energy and nutrient density diet without enzymes; (3) NC1+EC1; (4) NC2: negative control, diet formulated with 7% over-estimated crude protein and amino acids of soybean meal without enzymes; (5) NC2+EC2; (6) NC3: negative control, reduced energy and nutrient density diet and over-estimation of crude protein and amino acids of soybean meal; (7) NC3+EC1+EC2. Feeding NC1 or NC3 impaired feed conversion ratio at 7, 21 and 42 days, and NC2 at 21 days. Inclusion of EC2 in NC2 diet improved feed conversion ratio and kept it similar to basal diets from 1 to 21 days. Association of EC1 with EC2 in NC3 diet did not improve performance. In summary, inclusion of EC2 in diets with reduced nutrient density keep feed conversion ratio similar to basal diets from 1 to 21 days but does not improve performance of broiler chicken from 1 to 42 days post-hatch.