This study was conducted to relate the performance of broiler chickens fed diets containing growth-promoting antibiotics to changes in the intestinal microbiota. The technique of denaturing gradient gel electrophoresis (DGGE) of amplicons of the region V3 of 16S rDNA was used to characterize the microbiota. Two experiments were conducted, one with broilers raised in battery cages and the other with broilers raised in floor pens. Antibiotics improved the performance of the chickens raised in floor pens only. Avilamycin, bacitracin methylene disalicylate, and enramycin induced changes in the composition of the intestinal bacterial community of the birds in both experiments. The number of bacterial genotypes found in the intestinal tract of chickens was not reduced by the antibiotics supplemented in either environment. However, the changes in the composition of the intestinal bacterial community induced by antibiotics may be related to improvement in growth performance. This was indicated by the suppression of 6 amplicons and the presence of 4 amplicons exclusive to the treatment that had the best performance in the floor pen experiment.

Two experiments were carried out to assess the efficacy of plant extracts as alternatives for antimicrobial growth promoters in broiler diets. The performance experiment included 1,200 male broilers raised from 1 to 42 days of age. The metabolism experiment used 96 male broilers in the grower phase housed in metabolic cages for total excreta collection. At the end of the metabolism experiment, 24 birds were sacrificed to assess organ morphometrics. In both experiments, the following treatments were applied: control diet (CD); CD + 10 ppm avilamycin; CD + 1000 ppm oregano extract; CD + 1000 ppm clove extract; CD + 1000 ppm cinnamon extract; and CD + 1000 ppm red pepper extract. The microencapsulated extracts contained 20% of essential oil. No significant differences (P>0.05) in the studied performance parameters were observed among treatments. The dietary supplementation of the extracts did not influence (P>0.05) nitrogen-corrected apparent metabolizable energy values. In general, organ morphometrics was not affected by the experimental treatments, but birds fed the control diet had higher liver relative weight (P<0.05) as compared to those fed the diet containing red pepper extract, which presented the lowest liver relative weight. These results showed that there was no effect of the tested plant extracts on live performance or in organ morphometrics

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RESUMO -Objetivou-se avaliar o fornecimento de misturas de extratos vegetais nas dietas de frangos de corte.Utilizaram-se 1.350 aves distribuídas em blocos casualizados, com seis repetições e cinco dietas, uma sem aditivos e outras quatro, cada uma contendo um dos aditivos: 10 ppm de avilamicina; 200 ppm de um produto contendo óleos essenciais de cravo, tomilho, canela e pimenta; 100 ppm de um produto comercial composto de óleos essenciais sintéticos de orégano e canela e óleo-resina de pimenta microencapsulados; 500 ppm de um produto comercial constituído de óleo de eucalipto, óleo essencial de canela-da-china, folhas de boldo-do-chile e sementes de feno-grego na fase inicial e 1.200 ppm nas fases de crescimento e final. Aos 21 e 42 dias, foram avaliadas as variáveis de desempenho e aos 44 dias de idade, as características de carcaça. Dos 27 aos 30 dias de idade, foi realizado o ensaio de metabolismo pelo método de coleta total de excretas e determinadas a energia metabolizável e a digestibilidade da proteína bruta das dietas. As dietas com misturas de extratos vegetais não tiveram efeito significativo sobre o desempenho se comparadas à dieta sem aditivo e à dieta com antibiótico. A ausência de desafio na criação e a utilização de dietas com ingredientes de alta digestibilidade podem ter contribuído para que as aves expressassem todo o seu potencial, tornando indetectável a melhora ocasionada pela inclusão de qualquer dos aditivos. Dietas contendo misturas de extratos vegetais promovem desempenho semelhante ao obtido com dietas contendo antibiótico.Palavras-chaves: aditivos, características de carcaça, desempenho, ensaio de metabolismo Plant extracts in diets for broilersABSTRACT -The trial was carried out to evaluate different blends of plants extracts in broilers diets. It was used 1,350 broilers distributed in a randomized block design with six replicates and five diets, one without additive and the four others, each containing one of the following additives: 10 ppm of avilamycin; 200 ppm of a product containing essential oils of carnation, thyme, cinnamon and microencapsulated capsicum; 100 ppm of a product containing essential oils of synthetic cinnamaldehyde and carvacrol and capsicum oleoresin microencapsulated; 500 ppm of a commercial product containing eucalypt oil, essential oil of Chinese cinnamon, leaves of Chilene boldo and seeds of fenu-Greek at the initial phase and 1200 ppm in the grower and finisher phases. Performance parameters were evaluated at 21 and 42 days of age and the carcass characteristics at 44 days of age. From 27 to 30 days of age, it was carried out the metabolism trial trough total excreta collection method and metabolizable energy and the crude protein digestibility of the diets were determined. The diets with plant extract blends had no significant effect on the performance when compared to diet without additives or diet with avilamycin. The lack of challenge in the experimental facilities and the use of diets with high digestibility ingredients might have contributed to broil...

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This research aims to evaluate the microclimate of commercial loads of broiler chickens at different distances in the summer (rainy) and winter (dry) seasons and their effects on meat quality. Twelve broiler loads were monitored with a total of 24 crates per load. Data loggers were used to record temperature and relative humidity. The experiment followed a completely randomized design with 48 treatments in a factorial scheme (2 seasons: rainy and dry) x 2 (distances: short and long) x 12 (positions), with 3 replicates per experimental group. In the rainy season, meat quality was influenced by transport distance. For longer distances, it recorded the highest enthalpy comfort index (ECI), suggesting a tendency of dark, firm, and dry meat (DFD-like) and lower cooking losses (CL). The lowest ECI was recorded during the transport in dry season. Broiler chickens transported and slaughtered in the winter presented meat pH and L* (lightness) classified as "normal," but with higher cooking losses. For the shear force (SF), the seasons and distances had no significant influence on tenderness of the meat. Regarding the crate positioning in the load, no effect was observed during transport on this variable, given the meat quality characteristics of pH, L*, CL, and SF. These results suggest that the distance and the seasons present more influence on broiler meat quality than crate position in the truck.

O experimento avaliou o desempenho de frangos de corte suplementados em 4% na ração com três fontes de gordura: óleo ácido de soja (OAS4) e sebo bovino (SEBO4), óleo de soja (SOJA4) e misturas de 2% entre estas: (OAS2/SEBO2), (OAS2/SOJA2) e (SOJA2/SEBO2). Foram utilizados blocos casualizados, com 6 tratamentos, 6 repetições e 40 aves por parcela. Foram avaliadas as variáveis: consumo de ração (CR), ganho de peso (GP), peso vivo (PV), conversão alimentar (CA), fator de produção (FP) e viabilidade (VB), aos 42 dias de idade. Para análise, foram utilizados contrastes não ortogonais: 1- SOJA4 X (OAS4 + SEBO4 + OAS2/SEBO2); 2- SOJA4 X (OAS2/SOJA2 + SOJA2/SEBO2); 3- OAS2/SOJA2 X SOJA2/SEBO2; 4- OAS4 X OAS2/SOJA2; 5- OAS4 X OAS2/SEBO2. No contraste 1, observou-se um menor CR, melhor CA, superior GP, PV e FP para SOJA4 em relação a média OAS4, SEBO4 e OAS2/SEBO2. A comparação do SOJA4 com (OAS2/SOJA2 + SOJA2/SEBO2) do contraste 2 não foi significativa. O contraste 3 não indicou diferença entre OAS2/SOJA2 e SOJA2/SEBO2, exceto para VB. No contraste 4, OAS2/SOJA2 resultou em maior GP, PV e FP e melhor CA que OAS4. A mistura (OAS2/SEBO2) não foi vantajosa ao OAS4 para as variáveis (contraste 5). A gordura abdominal não foi afetada pelos tratamentos, somente a composição dos ácidos graxos das gorduras. O óleo de soja proporcionou melhor desempenho das aves, tanto em misturas 1:1 quanto como fonte única adicionada à ração. O óleo ácido de soja, o sebo e a mistura destes resultaram em depressão do desempenho das aves.