Flávia Oliveira Abrão

Aerobic fungi in the rumen fluid from dairy cattle fed different sources of forage

The objective of this study was to evaluate the aerobic microbiota of the rumen fluid from Holstein cows and heifers fed different tropical forage in the north of Minas Gerais, Brazil. A total of 30 samples of rumen fluid from cows fed with sorghum silage were collected: 32 from cows fed Brachiaria brizantha, 12 from heifers that received sorghum silage and 11 from calves fed sugar cane foliage. The culture was carried out using the agar Sabouraud medium and the solid C medium, containing microcrystalline cellulose. The isolated mycelial fungi were identified by microculture technique and yeasts by micromorphological and physical-chemical analysis. Specific identification for yeasts was confirmed by ribosomal DNA sequence analysis. The presence of fungal colonies was confirmed on the Sabouraud medium for 100% of the samples. No significant differences were observed comparing the concentrations of mycelia fungi in the rumen fluid from cows fed different forages and for the two categories evaluated, fed sorghum silage. Yeast populations in the rumen fluid from heifers fed sugarcane were higher compared with those receiving sorghum silage. The yeast Pichia kudriavzevii (Candida krusei) was the most frequent and among the mycelial fungi, the genus Aspergillus was the most frequently observed, corresponding to 56% of the samples. Future studies should elucidate the variations in the populations of these microorganisms considering the carbohydrate sources in the tropical forages and the animal categories. The ecological or pathogenic role of these microorganisms should also be considered, aiming at improved productivity and health of cattle.

Aerobe and anaerobe facultative Gram-negative bacteria rod-shaped in the ruminal fluid of dairy cattle fed with different diets containing tropical forages

The aim of this work was to analyse the population of aerobe and anaerobe facultative Gram-negative rod-shaped in the ruminal fluid of dairy cattle and calves fed with different sources of tropical forage. Samples of ruminal fluid were collected from 30 cows fed with sorghum silage, 32 cows fed with Brachiaria brizantha pasture, 12 calves fed with sorghum silage, and 11 calves fed with sugarcane. Fifteen ml of ruminal fluid were collected by sterile catheter and syringe puncture to the rumen. After serial decimal dilutions, samples were inoculated in plates containing MacConkey agar and incubated at 37 °C for 72 h. Calves fed with sorghum silage showed higher detection rate and larger population of these bacteria (8.4 X 10(6) colony forming units CFU/ml) when compared with adult cows fed with the same forage (1.4 X 10(5) CFU/ml). The most frequent genera identified in all groups were Enterobacter, Klebsiella, and Proteus. The most frequently identified bacteria in pasture-fed cows was Enterobacter spp., while Klebsiella spp. was the most frequently identified bacteria in cows fed with sorghum silage. Enterobacter spp. and Proteus spp. were more frequently observed in isolates from calves (P < 0.01). Future studies should clarify the differences between these populations.

Leveduras no rúmen de caprinos e bovinos de corte criados em pastagem tropicais

Em diferentes paises em todo o mundo, tem-se caracterizado a microbiota ruminal e registrado a importante participacao dos fungos na digestao e no equilibrio do ecossistema ruminal e na saude dos ruminantes. Entretanto, pouco se tem estudado sobre a caracterizacao e participacao de fungos aerobios em animais criados em condicoes extensivas, pastagens de baixo valor nutricional, frequentemente lignificadas. Pesquisas relacionadas ao ambiente ruminal de animais nessas circunstâncias permitiriam a selecao de isolados fungicos com atividade superior de enzimas celuloliticas e xilanoliticas, importantes na degradacao da parede celular vegetal.

Análise da contaminação parasitária em compostos orgânicos produzidos com biossólidos de esgoto doméstico e resíduos agropecuários

This research aimed at evaluating the cysts, oocysts and eggs contamination before and after thermal treatment of 60oC for 12 hours, in 25 different organic composts produced with biosolids from domestic waste-water treatment and animal and agricultural residues. The results showed high parasitological contamination for all organic composts before the treatment and these contaminations were not reduced after thermic treatment. The larva identification in coprocultures before and after thermic treatment showed Cooperia spp. and Trichostrongylus spp. were the most prevalent nematodes. These results demonstrated that helmintus’ eggs can remain viable even after the composing and thermic treatment. The obtained composition with sewage sludge and agricultural residues through these treatment processes can establish contamination risks for humans and animals.

Fungos aeróbios no intestino grosso de borregos e de ovelhas criados em pastagens tropicais

Fungi populations were evaluated in large intestine from sheep raised in the North of Minas Gerais, Brazil. The samples were from 39 Santa Ines crossbred ewes and 30 lambs raised on Tanzania grass (Panicum maximum cv. Tanzania), both supplemented with mineral mixtures. The clinical specimens were directly collected from rectal ampoule with sterile swabs. The development of fungal mycelium was observed in all lamb samples and positive cultures were observed in 34 ewe specimens (87.2%). After microculture of 40 colonies from lambs, 34 isolates of the genus Aspergillus, three of Paecilomyces spp., one Acremonium sp., and one Trichoderma sp. were identified. Out of the 39 isolates from ewes, 15 Paecilomyces spp., 11 Aspergillus spp., 11 Malbranchea spp., and one Onychocola sp. were identified. The results showed the predominance of the genus Aspergillus in the lambs, while the genus Paecilomyces, Malbranchea, and Aspergillus were predominant, in ewes.

Bastonetes Gram-negativos aeróbios e anaeróbios facultativos no fluido ruminal de bovinos de corte alimentados em pastagem lignificada e em novilhos com acidose ruminal

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.

Parasitological Contamination in Organic Composts Produced with Sewage Sludge

The activities performed daily by humans generate large volumes of waste from various areas, increasing environmental pollution and public health problems. According to the recommendations of the World Health Organization (WHO), the reactor effluent treatment from domestic sewages can be used in agriculture, since it applied to cultures that provide little risk of contamination with pathogens (Ayres & Mara, 1996). The sewage sludge is classified as class A when origins of processes with effective reduction of pathogens and can be used without restrictions in horticulture, and in the class B if results of processes of moderate reduction of pathogens, with more restricted use and be applied in reforestation and other cultures in which the risk of environmental and human contamination can be better controlled (Fernandes, 2000; David, 2002). Sewage sludge must have characteristics that allow its setting within the parameters set for each class (David, 2002). For class A, the most probable number of coliforms per gram of dried sludge must be less than 1000, and the parasitic contamination should be less than one viable egg of helminths in four grams of dried sludge and less than one egg per litre of effluent (WHO, 1989; Fernandes, 2000). The processes most often employed for the stabilization of sewage include the aerobic and anaerobic digestion. The application of lime and the composting are also recommended in some countries like USA, France and Brazil. However, the efficiency of the stabilization processes depends of the operational quality and of the pathogen characteristics present in the sewage sludge (Paulino et al., 2001).

Fungos anaeróbios do rúmen de bovinos e caprinos de corte criados em pastagens tropicais

The presence of anaerobic fungi structures was evaluated in ruminal juice of beef goats and beef cattle raised in the North of Minas Gerais, Brazil. The strains were collected from 18 Anglo-Nubian crossbred male goats and 23 Nellore crossbred steers during the dry period of the year. Physical-chemical characteristics of the juice were evaluated and direct examination with KOH digestion was performed for anaerobic fungi detection. Structures of these fungi were detected in samples of 14 (77.8%) goats and 17 (73.9%) steers. The monocentric fungi frequency (56.5%) was significantly higher in cattle than polycentric fungi frequency (26.1%). This study is the first report of anaerobic ruminal fungi in these ruminants in Brazil and showed high prevalence of theses microorganisms in the ruminal ecosystem of both animals.