Determinação e quantificação de protozoários ciliados e bactérias do rúmen de bovinos em pastagens temperadas e tropicais

Abstract

The objective of the present work was to identify and quantify the ciliate protozoa and crossbovine rumen bacteria (European x Nellore), with an average of 2.5 years, fed on winter pastures (Azevém and Aveia + Azevém) and summer (Brachiaria spp And Brachiaria spp. + Esrala Africana). Samples of ruminal contents were obtained from the center of the ruminal mass, after the slaughter of the animals. The total bacterial count (CBT), for solid and liquid fractions, was performed in plates with the aid of a manual colony counter. For the morphological analysis the Gram staining technique was used and the slides were read under an optical microscope with objective of 100x, being the bacteria classified in cocci and bacilli, gram positive and gram negative. The evaluation of the fermentative activity was evidenced by the growth of colonies with pink coloration through a carbohydrate source. The quantification and identification of ciliate genera were performed in Sedgewick-Rafter chamber under optical microscopy. The content of Dry Matter, Crude Protein, Mineral Matter, Neutral Detergent Fiber and Acid Detergent Fiber, In Vitro Digestibility in Dry Matter, Lignin, Cellulose and Hemicellulose were determined. The experimental design was completely randomized, with four treatments and 10 replicates for each treatment. The data were submitted to analysis using the methodology of Linear Models, generalized with Poisson distribution (1%) and the GENMOD procedure was used. Gram positive and negative bacteria were observed, in the forms cocci and bacilli and 11 genera of ciliate protozoa, being Diplodinium the predominant genus. The highest concentration of bacteria was found in winter forages (494.8 x1010 mL-1), with higher intensity in the Azevém pasture. In the ciliate protozoa, higher concentration was observed in the summer (200.70 x 10 4 mL-1), mainly in Brachiaria spp.