Quantificação das bactérias sólido-aderidas, bactérias e protozoários líquido-associados do rúmen de bovinos jovens alimentados com amiréia

Abstract

It were utilized four crossbreed, castrated, rumen cannuladed bovines, receiving dietary starea (containing 30% of urea) in the concentrate and corn silage, with the objective of quantify the liquid-associated bacteria and protozoa, solid-associated bacteria and related them with the ruminal pH. Three samples from ruminal content were harvested at 1 a.m., 2 a.m. and 30 min and 11 a.m. and 30 min after feeding. The microbial mass was quantified and qualified in the different fractions of solid-associated bacteria (SAB), liquid-associated bacteria (LAB) and liquid-associated protozoa (LAP) and their nitrogen contents (N), dry matter (DM) and organic matter (OM) were determined. The microbial population presented increasing contribution of SAB with the time, what did not occur with LAB and LAP. The level of OM in DM from the SAB increased as well, until 2 a.m. and 30 min when remains unaffected until 11 a.m. and 30 min. The nitrogen levels of the SAB expressed in the organic matter decreased in equal or superior time of harvest at 2 a.m. and 30 min, although the N level in the dry matter did not present this difference. The relations between bacteria:protozoa were equal to 1:2.1 at 1 hour, 2.6:1 at 2h and 30 min and 2.2:1 at 11h and 30 min after the feeding. It was still observed after feeding prevalence of protozoa and bacteria, both associated to the ruminal liquid. The total amounts and the ruminal microbial pool were not influenced by pH, probably because it always maintained itself above 6.39.