Microbial Populations in Ruminal Liquid Samples from Young Beefmaster Bulls at Both Extremes of RFI Values.

The gut microbiota is involved in the productivity of beef cattle, but the impact of different analysis strategies on microbial composition is unclear. Ruminal samples were obtained from Beefmaster calves (n = 10) at both extremes of residual feed intake (RFI) values (5 with the lowest and 5 with the highest RFI) from two consecutive days. Samples were processed using two different DNA extraction methods. The V3 and V4 regions of the 16S rRNA gene were amplified using PCR and sequenced with a MiSeq instrument (Illumina). We analyzed 1.6 million 16S sequences from all 40 samples (10 calves, 2 time points, and 2 extraction methods). The abundance of most microbes was significantly different between DNA extraction methods but not between high-efficiency (LRFI) and low-efficiency (HRFI) animals. Exceptions include the genus Succiniclasticum (lower in LRFI, p = 0.0011), and others. Diversity measures and functional predictions were also mostly affected by DNA extraction methods, but some pathways showed significant differences between RFI levels (e.g., methylglyoxal degradation, higher in LRFI, p = 0.006). The results suggest that the abundance of some ruminal microbes is associated with feed efficiency and serves as a cautionary tale for the interpretation of results obtained with a single DNA extraction method.

Effect of whole oilseeds in the diet on bacterial diversity in the solid fraction of the ruminal content of steers.

Our hypothesis was that different whole oilseeds included in the diet for steers confined could alter the diversity of rumen bacteria compared to a diet without oilseeds or an exclusively forage diet. It was aimed to evaluate the effects of oilseeds inclusion in the diet on bacterial diversity in the solid fraction of the ruminal content of steers, by gene sequences of the conserved 16S rDNA region. Six crossbred steers castrated males, fitted with ruminal cannula were used in a 6 × 6 Latin square design, using 21-day period. At the start of the experiment, the live weight of the animals averaged 416 ± 9.7 kg (mean ± SD). A total of 2,180,562 16S rDNA sequences were generated for the Bacteria domain by MiSeq sequencing. The bacterial diversity was composed of 24 bacterial phyla, with the most abundant being Firmicutes, Bacteroidetes, and Proteobacteria. Other phyla with less diversity were also identified including Eurychaeota, Tenericutes, SR1 Absconditalbacteria, Synergistetes, Actinobacteria, Saccharibacteria, Elusimicrobia, Cyanobacteria, Verrucomicrobia, Fusobacteria, Lentisphaerae. The similarity in the bacterial community averaged 50% for all the experimental diets. Steers-fed corn silage exhibited a great diversity of bacteria of the Firmicutes phylum. The steers-fed oilseeds in the diet had a great diversity of bacteria from the phylum Bacteroidetes and Proteobacteria. The inclusion of whole oilseeds in the steer diets can alter the rumen bacteria population by up to 50% of total diversity.

Cellulolytic activity of anaerobic facultative fungi from the digestive tract of sheep fed with banana leaf hay / Atividade celulolítica de fungos aeróbios facultativos do trato digestório de ovinos alimentados com feno da folha de bananeira

The addition of cellulolytic fungi, or their enzymes, in diets containing high levels of fiber are promising strategy for improving the performance. In this study, the aims were to select cellulolytic fungi from the digestive tract of sheep fed different concentrations of banana leaf hay. Thirty lambs raised in a feedlot were evaluated, distributed in a completely randomized design, with diets containing 0, 125, 250, 375, or 500 g/Kg of dry matter and six replications. Approximately 15 mL of ruminal fluid and swabs from the rectal ampulla were collected. The cultures were carried out in a medium containing microcrystalline cellulose (C medium). The mycelial fungi isolates were identified through the microculture technique. Among the fungi from the ruminal fluid, 23 isolates corresponded to the genus Aspergillus and three to Paecilomyces spp. Among the isolates from the rectal ampulla, seven were A. spp., and three were P. spp. The A. genus predominated among the isolates from both evaluated sites (p <0.05). Fragments of these fungi were inoculated in triplicate in medium C at 37 °C and the cellulolytic activity index (CAI) was determined after 24, 48, and 72 hours of incubation. There was no difference in the CAI of Aspergillus spp. from animals fed different diets or of different evaluated sites (P > 0.05). However, 22 isolates of Aspergillus spp. and three of Paecilomyces spp. showed a CAI > 1, indicating biotechnological potential for cellulase production. These selected isolates could be selected for the elaboration of microbial additives in ruminant diets.(AU)

A adição de fungos celulolíticos, ou suas enzimas, em dietas contendo elevados teores de fibras são estratégias pro-missoras para melhorar o desempenho. Neste estudo os objetivos foram selecionar fungos celulolíticos do trato digestório de ovinos alimentados com diferentes concentrações do feno da folha da bananeira (FBH). Foram avaliados 30 borregos criados em sistema intensivo, distribuídos em delineamento inteiramente ao acaso, com cinco dietas contendo 0, 125, 250, 375 ou 500 g/KG de matéria seca em seis repetições. Foram coletados aproximadamente 15 mL de fluido ruminal e swabs da ampola retal. Os cultivos foram realizados em meio de cultura contendo celulose microcristalina (meio C). Os fungos micelianos foram identificados após a técnica de microcultivo. Entre os fungos provenientes do fluido ruminal, 23 isolados corresponderam ao gênero Aspergillus e três a Paecilomyces spp.. Foram identificados nas fezes dos animais sete Aspergillus spp. e três Paecilomyces spp.. O gênero Aspergillus predominou entre os isolados de ambos os sítios avaliados (p =0,013). Fragmentos desses fungos foram inoculados em triplicada em meio C a 37 °C e determinou-se o índice de atividade celulolítica(IAC) após 24, 48 e 72 horas de incubação. Não houve diferença entre CAI de isolados de Aspergillus spp. provenientes dos animais em diferentes dietas ou sítios avaliados (P > 0.05). Entretanto, 22 isolados de Aspergillus spp. e três de Paecilomyces spp. apresentaram IAC >1, indicando potencial biotecnológico para produção de celulases.(AU)

Bacterial species in the ruminal content of steers fed oilseeds in the diet.

The aim of this study was to evaluate bacterial species and diversity of methanogenic Archaea in the solid fraction of the ruminal content, through the gene sequences of the conserved 16S rDNA region, in response to the following diets: canola, cottonseed, sunflower, soybean, corn silage, and control diet. Six rumen-fistulated crossbred steers, with body weight (BW) of 416.33 ± 93.30 kg, were distributed in a 6 × 6 Latin square design. Regardless of the diet provided, amylolytic, proteolytic, and lactic bacteria were identified in the rumen fluid. Cellulolytic bacteria were predominant for all diets, reaching 47.75% of operational taxonomic units (OTUs) in animals fed with the cottonseed diet. Amylolytic bacteria reach 62.51% of OTU in animal fed sunflower diet, while proteolytic bacteria correspond to 65.96% of OTU in this same diet. Also, Megasphaera elsdenii bacterium was identified for all diets, with a greater percentage of OTU in steers fed the cottonseed diet. The diversity analysis of the species identified the methanogenic Archaea Methanobrevibacter ruminantium in all diets. We conclude that the control and corn silage diets have the most similar bacterial flora; diets with oilseeds had 47.5% similarity in rumen flora bacteria species. Animals fed with soybean showed a reduced number of methanogenic Archaea in the rumen content, which could be an alternative feed for cattle due to their low potential for energy losses with the production of methane.

Perspectivas do uso de extratos de plantas amazônicas (açaí, copaíba, salva-do-marajó, pupunha e bacuri) como potenciais moduladores da fermentação ruminal: um breve panorama / Perspectives on the use of extracts from Amazonian plants and fruits (açai, copaiba, salva-do-marajo, pupunha and bacuri) as potential modulators of ruminal fermentation: a brief overview / Perspectivas del uso de extractos de plantas y frutos amazónicos (açaí, copaíba, salva-do-marajó, pupunha y bacuri) como potenciales moduladores de la fermentación ruminal: un breve panorama

Resumo Na flora amazônica, incontáveis plantas possuem compostos bioativos, que potencialmente podem ser utilizados como moduladores da fermentação ruminal. Apesar da importância, poucos estudos têm sido desenvolvidos para avaliar a utilização de plantas amazônicas como aditivos alimentares naturais na nutrição de ruminantes. Assim, objetiva-se apresentar um panorama dos dados científicos da literatura sobre os efeitos do uso dos extratos de açaí, copaíba, salva-do-marajó, pupunha e bacuri na fermentação ruminal e os seus potenciais de utilização na dieta de ruminantes. O açaí (Euterpe oleracea Mart.), possui 16,08 mg/g de matéria seca de flavonoides, compostos com potente ação antimicrobiana. Estudos com suplementação do óleo de açaí tem mostrado efeitos modulatórios na fermentação ruminal e na produção de leite de ovelhas e vacas. Adicionalmente, a oleoresina de copaíba (Copaifera spp.) e a manteiga das sementes de bacuri (Platonia insignis Mart.), possuem, respectivamente, 88% e 41% de terpenos; a composição fitoquímica do óleo de salva-do-marajó (Hyptis crenata Pohl ex Benth) ainda não está completamente caracterizada, mas esta fonte está majoritariamente composta por terpenos cânfora (33,62%), 1,8-cineol (19,76%) e α-pineno (15,24%), que apresentam atividade in vitro antimicrobiana, capaz de reduzir a produção total de gás em ambiente ruminal in vitro. A pupunha, fruto da pupunheira (Bactris gasipaes Kunth.), possui 355,95 mg/kg de carotenoides, com efeito antimicrobiano in vitro contra algumas cepas bacterianas. Os achados desta revisão demonstram as potencialidades dos extratos amazônicos na maximização da produção animal, em razão dos possíveis efeitos na modulação da fermentação ruminal, sendo encorajada a realização de estudos adicionais visando uma maior exploração deles. Embora, atualmente, não existam estudos associados aos efeitos do açaí, salva-do-marajó, pupunha e bacuri na fermentação ruminal, pressupõe-se que pela sua composição fitoquímica, poderiam ter um efeito semelhante aos ionóforos na produção de ruminantes.

Abstract In the Amazonian Forest, diverse plants have bioactive compounds, which can potentially be used as modulators of ruminal fermentation. Despite the importance, few studies have been developed to evaluate the use of extracts from Amazonian plants as natural feed additives in ruminant nutrition. Thus, the objective of this study is to present a brief overview of the scientific data in the literature regarding the effects of the use of extracts of açaí, copaíba, sage-do-marajó, peach palm, and bacuri on the ruminal fermentation and their potential for use in the diet of ruminants. Açaí (Euterpe oleracea Mart.) has 16.08 mg/g of dry matter of flavonoids, compounds with potent antimicrobial activity. Studies with açaí oil supplementation have shown modulatory effects on rumen fermentation and milk production in sheep and cows. Additionally, the copaiba oleoresin (Copaifera spp.) and the bacuri (Platonia insignis Mart.) seed butter have 88% and 41% of terpenes, respectively; the phytochemical composition of marajó sage oil (Hyptis crenata Pohl ex Benth) is not completely resolved, but this source is mostly composed of the terpenes, camphor (33.62%), 1,8-cineole (19.76%) and α-pinene (15.24%), which have in vitro antimicrobial effects against different bacterial strains. The findings of this review demonstrate the potential of Amazonian extracts in maximizing animal production, due to the possible effects on the modulation of ruminal fermentation, being encouraged to carry out additional studies aiming at a greater exploration of them. Although, there are no current studies associated with the effects of açaí, sage, peach palm, and bacuri on rumen fermentation, it is inferred that, due to their phytochemical composition, they may have a similar effect to ionophores on ruminant production.

Resumen En la selva amazónica, innumerables plantas poseen compuestos bioactivos, que potencialmente pueden ser utilizados como moduladores de la fermentación ruminal. A pesar de la importancia, han sido desarrollados pocos estudios evaluando el uso de extractos de plantas amazónicas como aditivos alimentarios naturales en la nutrición de rumiantes. Así, el objetivo de este estudio es presentar un breve panorama de los datos científicos en la literatura sobre los efectos del uso de extractos de açaí, copaíba, salvia-do-marajó, chontaduro y bacuri en la fermentación ruminal y su potencial de uso en la dieta de los rumiantes. Açaí (Euterpe oleracea Mart.) tiene 16,08 mg/g de materia seca de flavonoides, compuestos con potente acción antimicrobiana. Los estudios con suplementos de aceite de açaí han demostrado efectos moduladores sobre la fermentación ruminal y la producción de leche en ovejas y vacas. Adicionalmente, la oleorresina de copaiba (Copaifera spp.) y la mantequilla de semilla de bacuri (Platonia insignis Mart.) poseen 88% y 41% de terpenos, respectivamente; la composición fitoquímica del aceite de salvia de marajó (Hyptis crenata Pohl ex Benth) no está completamente resuelta, sin embargo esta fuente está mayoritariamente compuesta de los terpenos alcanfor (33,62%), 1,8-cineol (19,76%) y α-pineno (15,24%), los cuales poseen efecto antimicrobiano in vitro frente a diferentes cepas bacterianas. Los hallazgos de esta revisión demuestran el potencial de los extractos amazónicos en la maximización de la producción animal, debido a sus posibles efectos sobre la modulación de la fermentación ruminal, siendo incentivados a realizar estudios adicionales con el objetivo de una mayor exploración de estos. Aunque actualmente no existen estudios asociados a los efectos del açaí, la salvia, el chontaduro y el bacuri en la fermentación ruminal, se supone que, por su composición fitoquímica, podrían tener un efecto similar a los ionóforos en la producción de rumiantes.

Performance and microbiota of the digestive tract of Nellore calves supplemented with fungi isolated from bovine rumen.

BACKGROUND AND AIM: In tropical semiarid regions, supplementation with fungi could contribute to rumen modulation, promoting greater production of fibrolytic enzymes and degradation of forage. The objective of this study was to analyze the effect of supplementation with fungi, isolated from the bovine rumen, on the performance and microbiota of the digestive tract of Nellore calves. MATERIALS AND METHODS: The experiment was conducted in randomized blocks evaluating eight Nellore calves that were daily supplemented with isolates of Aspergillus terreus and Trichoderma longibrachiatum, along with eight calves that were not supplemented. After 55 days, the animals were weighed, and samples of rumen fluid and feces were collected for analysis. The characteristics that showed normal distribution were subjected to analysis of variance and compared using Tukey's test. Whereas, the variables that did not show normal distribution were subjected to the Kruskal-Wallis test, and the frequencies of the bacterial and fungal genera were compared using the Chi-square test. RESULTS: Supplementation with fungi promoted the reduction in ruminal pH (p<0.05). However, the final live weight; average daily weight gain; total weight gain; rumen protozoa; and the count of Enterobacteriaceae, mycelial fungi, and yeasts of ruminal fluid and feces were not influenced by supplementation (p>0.05). Moreover, the protozoa Eodinium spp. was identified only in supplemented calves (p<0.05). CONCLUSION: Supplementation with the fungi presented the potential for use as possible additives because it did not alter the physiological parameters of the facultative anaerobic microbiota composition in the rumen and feces. In addition, it favored the presence of the ciliate genus Eodinium. However, further studies should be performed to better define suitable dosages for supplementation.

Disentangling the Complexity of the Rumen Microbial Diversity Through Fractionation Using a Sucrose Density Gradient.

The ruminal microbial community is an important element in health, nutrition, livestock productivity, and climate impact. Despite the historic and current efforts to characterize this microbial diversity, many of its members remain unidentified, making it challenging to associate microbial groups with functions. Here we present a low-cost methodology for rumen sample treatment that separates the microbial community based on cell size, allowing for the identification of subtle compositional changes. In brief, the sample is centrifuged through a series of sucrose density gradients, and cells migrate to their corresponding density fraction. From each fraction, DNA is extracted and 16S rRNA gene amplicons are sequenced. We tested our methodology on four animals under two different conditions, fasting, and post-feeding. Each fraction was examined by confocal microscopy showing that the same sucrose fraction consistently separated similar cell-sized microorganisms independent of the animal or treatment. Microbial composition analysis using metabarcoding showed that our methodology detected low abundance bacterial families and population changes between fasting and post-feeding treatments that could not be observed by bulk DNA analysis. In conclusion, the sucrose-based method is a powerful low-cost approximation to untwine, enrich, and potentially isolate uncharacterized members of the ruminal microbiome.

Sheep fed with banana leaf hay reduce ruminal protozoa population.

A ciliate protozoa suppression can reduce methane production increasing the energy efficiency utilization by ruminants. The physicochemical characteristics of rumen fluid and the profile of the rumen protozoa populations were evaluated for sheep fed banana leaf hay in replacement of the Cynodon dactylon cv. vaqueiro hay. A total of 30 male sheep were raised in intensive system during 15 days of adaptation and 63 days of experimental period. The animals were distributed in a completely randomized design that included six replicates of five treatments with replacement levels (0, 25, 50, 75, and 100%) of the grass vaquero for the banana leaf hay. Samples of fluid were collected directly from the rumen with sterile catheters. Color, odor, viscosity, and the methylene blue reduction potential (MBRP) were evaluated and pH estimated using a digital potentiometer. After decimal dilutions, counts of genus protozoa were performed in Sedgewick Rafter chambers. The averages of pH, MBRP, color, odor, and viscosity were not influenced by the inclusion of the banana leaf hay. However, the total number of protozoa and Entodinium spp. population significantly decreased at 75 and 100% inclusions of banana leaf hay as roughage.

Physico-chemical and microbiological characterization of ruminal fluid from gastrointestinal contents of Holstein calves in artificial fed milk conventional or fractionated / Caracterização físico-química e microbiológica do fluido ruminal e do conteúdo gastrointestinal de bezerros holandeses em aleitamento artificial convencional ou fracionado

The fractional artificial feeding has allowed provide an adequate amount of milk to calves in the first weeks of life and restrict at weaning, stimulating growth and favoring better adaptation to diets with forage and concentrates. The aim was to evaluate the ruminal characteristics and gastrointestinal microbiota of dairy calves in different feeding systems. Holstein calves were evaluated in randomly assigned to feed milk conventional that consisted of four liters of milk daily for 60 days or fractionated systems, six liters of 6º to 25º, four liters of 26º to 45º and two liters of 46º to 60º days old. At an end of the experimental period, the animals were euthanized, and approximately 15 mL of rumen, abomasum and intestine contents were collected for physicochemical and microbiological analysis to detection of fungi, protozoa and Enterobacteriaceae. Feeding systems did not influence characteristics of color, odor and viscosity of rumen fluid. The analysis of pH and quantification of Enterobacteriaceae, mycelial fungi and yeast showed no significant difference between treatments at the different sites. The Escherichia and Proteus genus were the most frequent for the gastrointestinal tract for both feed system. However, E. coli was significantly more frequent among isolates from the rumen fluid of calves in conventional feeding, which could suggest an imbalance in this ecosystem. Thus the artificial fed milk systems influenced the genus profile of Enterobacteriacea in the rumen and small intestine of calves.(AU)

O aleitamento artificial fracionado tem permitido fornecer quantidade adequada de leite aos bezerros nas primeiras semanas de vida e restringir na desmama, estimulando o melhor crescimento e adaptação a dietas com volumosos e concentrados. Objetivou-se avaliar as características ruminais e a microbiota gastrointestinal de bezerros leiteiros em diferentes sistemas de aleitamento. Foram utilizados 12 bezerros Holandeses, distribuídos aleatoriamente em dois tratamentos. No aleitamento convencional, foram fornecidos quatro litros de leite diários; no fracionado, seis litros do 6º ao 25º dia, quatro litros do 26 ao 45 e dois litros por dia do 46 ao 60 dia. Ao final do período experimental, os animais foram eutanasiados e aproximadamente 15 mL dos conteúdos do rúmen, abomaso e intestino foram coletados para análises físicas, químicas e microbiológicas para detecção de Enterobacteriaceae, fungos e protozoários. Os sistemas de aleitamento não influenciaram nas características de cor, odor e viscosidade do líquido ruminal. O pH e a quantificação de protozoários, Enterobacteriaceae, fungos micelianos e leveduriformes não apresentaram diferença significativa entre os tratamentos, nos diferentes sítios avaliados. Os gêneros Escherichia e Proteus foram os mais frequentes entre as amostras dos conteúdos avaliados, para ambos os sistemas de aleitamento. Entretanto, E. coli foisignificativamente mais frequente entre os isolados provenientes do fluido ruminal de bezerros em aleitamentoconvencional, o que poderia sugerir um desequilíbrio nesse ecossistema. Dessa forma constatou-se que os sistemas de aleitamentos influenciaram o perfil de gêneros de Enterobacteriaceae no rúmen e intestinos dos bezerros.(AU)

Physico-chemical and microbiological characterization of ruminal fluid from gastrointestinal contents of Holstein calves in artificial fed milk conventional or fractionated / Caracterização físico-química e microbiológica do fluido ruminal e do conteúdo gastrointestinal de bezerros holandeses em aleitamento artificial convencional ou fracionado

The fractional artificial feeding has allowed provide an adequate amount of milk to calves in the first weeks of life and restrict at weaning, stimulating growth and favoring better adaptation to diets with forage and concentrates. The aim was to evaluate the ruminal characteristics and gastrointestinal microbiota of dairy calves in different feeding systems. Holstein calves were evaluated in randomly assigned to feed milk conventional that consisted of four liters of milk daily for 60 days or fractionated systems, six liters of 6º to 25º, four liters of 26º to 45º and two liters of 46º to 60º days old. At an end of the experimental period, the animals were euthanized, and approximately 15 mL of rumen, abomasum and intestine contents were collected for physicochemical and microbiological analysis to detection of fungi, protozoa and Enterobacteriaceae. Feeding systems did not influence characteristics of color, odor and viscosity of rumen fluid. The analysis of pH and quantification of Enterobacteriaceae, mycelial fungi and yeast showed no significant difference between treatments at the different sites. The Escherichia and Proteus genus were the most frequent for the gastrointestinal tract for both feed system. However, E. coli was significantly more frequent among isolates from the rumen fluid of calves in conventional feeding, which could suggest an imbalance in this ecosystem. Thus the artificial fed milk systems influenced the genus profile of Enterobacteriacea in the rumen and small intestine of calves.

O aleitamento artificial fracionado tem permitido fornecer quantidade adequada de leite aos bezerros nas primeiras semanas de vida e restringir na desmama, estimulando o melhor crescimento e adaptação a dietas com volumosos e concentrados. Objetivou-se avaliar as características ruminais e a microbiota gastrointestinal de bezerros leiteiros em diferentes sistemas de aleitamento. Foram utilizados 12 bezerros Holandeses, distribuídos aleatoriamente em dois tratamentos. No aleitamento convencional, foram fornecidos quatro litros de leite diários; no fracionado, seis litros do 6º ao 25º dia, quatro litros do 26 ao 45 e dois litros por dia do 46 ao 60 dia. Ao final do período experimental, os animais foram eutanasiados e aproximadamente 15 mL dos conteúdos do rúmen, abomaso e intestino foram coletados para análises físicas, químicas e microbiológicas para detecção de Enterobacteriaceae, fungos e protozoários. Os sistemas de aleitamento não influenciaram nas características de cor, odor e viscosidade do líquido ruminal. O pH e a quantificação de protozoários, Enterobacteriaceae, fungos micelianos e leveduriformes não apresentaram diferença significativa entre os tratamentos, nos diferentes sítios avaliados. Os gêneros Escherichia e Proteus foram os mais frequentes entre as amostras dos conteúdos avaliados, para ambos os sistemas de aleitamento. Entretanto, E. coli foisignificativamente mais frequente entre os isolados provenientes do fluido ruminal de bezerros em aleitamentoconvencional, o que poderia sugerir um desequilíbrio nesse ecossistema. Dessa forma constatou-se que os sistemas de aleitamentos influenciaram o perfil de gêneros de Enterobacteriaceae no rúmen e intestinos dos bezerros.

Bastonetes Gram-negativos aeróbios e anaeróbios facultativos no fluido ruminal de bovinos de corte alimentados em pastagem lignificada e em novilhos com acidose ruminal / Aerobes and anaerobe facultative Gram-negative rod-shaped bacteria in the ruminal fluid of beef cattle fed lignified pasture and steers with ruminal acidosis

Objetivou-se analisar a população de bastonetes Gram negativos aeróbios e anaeróbios facultativas no suco ruminal bovinos zebuínos de diferentes categorias, alimentados em pastagem tropical, e de novilhos alimentados com alto teor de grão e sem volumosos. Foram coletados fluido ruminal de 32 vacas, 50 novilhos e 50 bezerros alimentadas em pastagem de Brachiaria spp. e de 20 novilhos com acidose ruminal. Após diluições decimais, amostras foram inoculadas em placas contendo ágar MacConkey a 39°C. Para a identificação dos gêneros mais frequentes foram utilizadas provas bioquímicas. A concentração dessas bactérias não diferiu no ambiente ruminal de vacas, novilhos e bezerros de corte alimentados com pastagem tropical lignificada. Os gêneros mais frequentemente identificados para esses animais foram Escherichia, Enterobacter e Klebsiella. Novilhos alimentados sem volumoso e com acidose apresentaram maior taxa de detecção e maior população dessas bactérias no ambiente ruminal (>6 log/ml) quando comparados aos novilhos alimentados somente em pastagem. A espécie Escherichia coli foi predominante entre as bactérias isoladas do fluido ruminal de novilhos alimentados com dieta com alta concentração de grãos e com acidose (p<0,01). Constatou-se que em bovinos de corte, criados em pastagem tropical lignificada, a população desses microrganismos é baixa no ambiente ruminal e com maior diversidade de gêneros bacterianos. Entretanto em novilhos confinados e alimentos sem volumoso, apresentando acidose ruminal subaguda, ocorre desequilíbrio populacional com aumento da população de E. coli.(AU)

This study aimed to analyze the population of Gram negative bacteria, rod-shaped aerobic and facultative anaerobes, in ruminal fluid of health Zebu cattle of different categories fed in tropical pasture and steers fed high levels of grain and without bulky. Rumen fluid from 32 cows, 50 steers and 50 calves fed on Brachiaria spp. and 20 steers with ruminal acidosis were collected. After decimal dilutions, the samples were inoculated on petri dishes with agar MacConkey at 39°C. Biochemical tests were used to identify the most common genera these bacteria. The concentration of these bacteria did not differ in the rumen of cows, calves and calves fed lignified tropical pasture and the most frequently identified genera for these animals were Escherichia, Enterobacter and Klebsiella. However, steers fed without forage and with acidosis showed a higher detection rate and larger population of these bacteria in the rumen (>6 log/ml) compared to steers fed only pasture. The Escherichia coli species was predominant among theses bacteria isolated from the rumen fluid of steers with acidosis (p<0.01). In beef zebu cattle raised on pasture lignified, the population of these microorganisms in the rumen is low showing greater diversity of genera. However in confined zebu steers fed without forage and with sub acute ruminal acidosis occur disequilibrium with increased E. coli population.(AU)

Bastonetes Gram-negativos aeróbios e anaeróbios facultativos no fluido ruminal de bovinos de corte alimentados em pastagem lignificada e em novilhos com acidose ruminal / Aerobes and anaerobe facultative Gram-negative rod-shaped bacteria in the ruminal fluid of beef cattle fed lignified pasture and steers with ruminal acidosis

Objetivou-se analisar a população de bastonetes Gram negativos aeróbios e anaeróbios facultativas no suco ruminal bovinos zebuínos de diferentes categorias, alimentados em pastagem tropical, e de novilhos alimentados com alto teor de grão e sem volumosos. Foram coletados fluido ruminal de 32 vacas, 50 novilhos e 50 bezerros alimentadas em pastagem de Brachiaria spp. e de 20 novilhos com acidose ruminal. Após diluições decimais, amostras foram inoculadas em placas contendo ágar MacConkey a 39°C. Para a identificação dos gêneros mais frequentes foram utilizadas provas bioquímicas. A concentração dessas bactérias não diferiu no ambiente ruminal de vacas, novilhos e bezerros de corte alimentados com pastagem tropical lignificada. Os gêneros mais frequentemente identificados para esses animais foram Escherichia, Enterobacter e Klebsiella. Novilhos alimentados sem volumoso e com acidose apresentaram maior taxa de detecção e maior população dessas bactérias no ambiente ruminal (>6 log/ml) quando comparados aos novilhos alimentados somente em pastagem. A espécie Escherichia coli foi predominante entre as bactérias isoladas do fluido ruminal de novilhos alimentados com dieta com alta concentração de grãos e com acidose (p<0,01). Constatou-se que em bovinos de corte, criados em pastagem tropical lignificada, a população desses microrganismos é baixa no ambiente ruminal e com maior diversidade de gêneros bacterianos. Entretanto em novilhos confinados e alimentos sem volumoso, apresentando acidose ruminal subaguda, ocorre desequilíbrio populacional com aumento da população de E. coli...

This study aimed to analyze the population of Gram negative bacteria, rod-shaped aerobic and facultative anaerobes, in ruminal fluid of health Zebu cattle of different categories fed in tropical pasture and steers fed high levels of grain and without bulky. Rumen fluid from 32 cows, 50 steers and 50 calves fed on Brachiaria spp. and 20 steers with ruminal acidosis were collected. After decimal dilutions, the samples were inoculated on petri dishes with agar MacConkey at 39°C. Biochemical tests were used to identify the most common genera these bacteria. The concentration of these bacteria did not differ in the rumen of cows, calves and calves fed lignified tropical pasture and the most frequently identified genera for these animals were Escherichia, Enterobacter and Klebsiella. However, steers fed without forage and with acidosis showed a higher detection rate and larger population of these bacteria in the rumen (>6 log/ml) compared to steers fed only pasture. The Escherichia coli species was predominant among theses bacteria isolated from the rumen fluid of steers with acidosis (p<0.01). In beef zebu cattle raised on pasture lignified, the population of these microorganisms in the rumen is low showing greater diversity of genera. However in confined zebu steers fed without forage and with sub acute ruminal acidosis occur disequilibrium with increased E. coli population...