Utilization of corn-based diets supplemented with an exogenous α-amylase for broilers.

A study was conducted to evaluate the effects of a supplemental α-amylase on energy and nutrient utilization of broiler chickens fed diets with variable amounts of corn. A total of 480 slow feathering Cobb × Cobb 500 male broilers were randomly distributed into 10 treatments with 8 replicates of 6 birds each. Birds were fed a common starter to 14 D post-hatch. The experimental diets were provided subsequently until 25 D, which were a conventional corn-soy basal diet (CS) and a corn-soy diet displaced with 40% of corn (CN). These were fed as-is or supplemented with 40, 80, 120, or 160 kilo-Novo α-amylase units (KNU)/kg. Dietary treatments were distributed factorially as a 2 × 5 arrangement (diet type vs. amylase). Samples of feed, excreta, and ileal digesta were analyzed for determination of ileal digestible energy (IDE), ME, total tract retention, and digestibility of dry matter, protein, and fat. No interactions between diet type and amylase were observed. The CN diet had lower (P < 0.05) energy utilization and nutrient digestibility when compared to the CS diet. AMEn and IDE increased (P < 0.05) by 110 and 207 kcal/kg, respectively, when CS and CN diets were supplemented with 80 KNU/kg. The amylase added to the CS diet led to quadratic increases (P < 0.05) on growth performance, IDE, AME, and AMEn, as well as in dry matter, protein, and fat digestibility. Energy utilization and crude protein digestibility were linearly increased (P < 0.05) when amylase was added to the CN diet or the extrapolated 100% of corn. In conclusion, energy utilization, digestibility of crude protein, fat, and dry matter increased with amylase supplementation in corn-soy-based diets. When amylase was tested in a complete diet having 53.6% corn, 100 and 105 KNU/kg maximized AMEn and IDE, respectively; however, the maximum energy response in the CN diet or 100% of corn was not achieved until 160 KNU/kg, suggesting an association between amylase dose optimization and dietary starch concentration.

Caracterização epidemiológica da doença de newcastle em frangos de corte do estado de minas gerais no período de 1988 a 1998

ABSTRACT The present study analyzed the occurrence of Newcastle disease in the commercial poultry population in all major regions of Minas Gerais, Brazil. The main objective was to investigate the impact of regional patterns of production on the epidemiology of the disease. The study was based on data collected from 797 diagnosis files of laboratory results of samples processed from 1988 up to 1998. The small number of cases of virus isolation encountered suggest that the incidence of Newcastle disease in Minas Gerais was very low over the period, although sporadic foci have occurred. The vaccination antibody titer responses were adequate and within the recommended standards. Some marked regional differences were found. In the region Triângulo Mineiro/Alto Paranaíba, Brazil, the incidence of HI titers indicative of contact with the virus was very low, confirming that vaccination is not carried out and natural challenge rarely occurs. Conversely, vaccination is a common practice in the other regions studied, but the incidence of contact with wild virus was significantly (p > 0.05) higher than in the former region. Vaccinated broilers HI antibody titers indicative of protection were found in adequate proportions

RESUMO No presente estudo foram analisados 791 exames laboratoriais para frangos de corte do Estado de Minas Gerais, no período de 1988 a 1998. Foram descritas as formas de ocorrência da doença de Newcastle (DNC) no estado, investigando a sua relação com o sistema de produção e com os mecanismos de prevenção sanitária a estes associados. O pequeno número de isolamento viral encontrado possibilita formular a hipótese de que a incidência da DNC foi muito baixa, durante os 11 anos estudado, embora focos esporádicos da doença tenham sido detectados. Observaramse diferenças significativas entre as mesorregiões mineiras, quando comparados os títulos de anticorpos antivírus da DNC considerados negativos para a presença do vírus, positivos vacinais ou positivos com títulos de IH para o vírus da DNC de desafio. No Triângulo Mineiro/Alto Paranaíba, os títulos de IH negativos confirmaram que a vacinação não é praticada pela maioria das granjas e o contato com vírus de campo foi mínimo, indicando que as condições sanitárias e de biosseguridade permitem a não utilização de vacinas contra a DNC. Já nas outras mesorregiões estudadas, a vacinação é realizada como rotina, apresentando bom índice de proteção vacinal (56%). O contato com o vírus de campo foi maior, justificando o uso de vacinação como forma de garantir aves livres da DNC.

Bronquite infecciosa das galinhas / Avian infectious bronchitis

RESUMO A bronquite infecciosa das galinhas (BIG) é uma doença respiratória altamente contagiosa causada por um Coronavírus, o vírus da bronquite infecciosa das galinhas (VBIG). Embora o VBIG seja um patógeno primário do trato respiratório, ele é também uma causa comum de redução da produção e qualidade dos ovos em galinhas. Certos tipos de VBIG causam lesões renais, com significativa mortalidade. Há também mortalidade por conseqüências respiratórias. A doença possui grande importância econômica devida às perdas na produção, sendo estas maiores que as perdas por mortalidade. A ocorrência de múltiplos sorotipos e as características mutantes de seu agente etiológico tem complicado e aumentado os custos de produção e dificultado sua prevenção através da imunização. Recentemente, uma variante do VBIG tem sido descrita associado com a miopatia dos músculos peitorais em muitas partes do mundo, inclusive no Brasil.

ABSTRACT Avian infectious bronchitis (IB) is a highly contagious respiratory disease of chickens caused by a Coronavirus, infectious bronchitis virus (IBV). Although IBV is primarily a respiratory tract pathogen, it is also a common cause of reduced egg production and egg quality in laying hens, and certain strains of IBV cause kidney lesions with significant mortality. Mortality by tracheal blockage also occurs. The disease has high economic importance due the loss of production, which is more important than the loss by mortality. The occurrence of multiple serotypes and mutants of the IBV have complicated and increased the production costs and have impaired its prevention through immunization. Recently, a variant IBV has been reported associated with pectoral muscle myopathy in many parts of world including Brazil.