The Isolation and Preliminary Study of Some Physiological Characteristics of the Predominating Flora from the Rumen of Cattle and Sheep

Abstract

Studies on the predominating bacteria of the rumen of cattle and sheep were carried out on animals fed normal and exptl. diets. The most satisfactory samples were obtained from animals having rumen fistulae, from which rumen contents could be drawn without undue aeration. Samples obtained by stomach tube were not as satisfactory. Direct counts were made, using nigrosine, an indirect stain, to serve as a guide for the success or failure of the cultural work. The use of nigrosine overcame difficulties caused by artifacts incurred in direct staining. The cultural procedure was carried out under anaerobic conditions which were maintained by a vaspar seal during incubation at 38[degree]C. A series of 10-fold dilutions up to 10 -12 was inoculated into a rich organic broth at pH 6. It was shown by these methods that about 100 billion bacteria per gram were present in the fresh solid rumen contents, in both cattle and sheep on normal diets. When good cultural conditions prevailed, as in the case of the fistulated bull, the cultural results showed agreement with the slide counts in 24 out of 26 cases. Samples from fistulated sheep did not show as good agreement as only 3 out of 8 samples grew in the expected dilution. This probably was due to less favorable cultural conditions. Poor cultural results were obtained consistently when samples were obtained by stomach tube, probably due to aeration. Liquid samples had a lower bacterial content than solid samples taken simultaneously from the same animal. Aspirated samples showed lower bacterial content than liquid samples obtained from fistulated animals. Many bacteria from the highest dilutions of rumen contents from both sheep and cattle were able to break down cellulose and to utilize urea, as was shown by testing the pure cultures for these characteristics. All bacteria isolated from the highest dilutions of rumen contents were anaerobic.