The experiments were carried out on 24 Bufflo rats (12 male and 12 female). The animals were fed ad libitum with LSM granules for rodents. Access to water was unlimited. After the end of the experiments the rats were put to ether narcosis, while smear tests from mouth and pharynx were done and then blood from jugular vein was taken. After putting to sleep stomach and caecal were withdrawn and then their contents. The withdrawn contents were cultured on the bacteriological ground. The number of erythrocytes and leucocytes as well as haemoglobin and haemocrit were marked in blood. Glucose, total protein, total cholesterol and triglycerides were marked in blood serum. Artificial saliva and distilled water in equal amounts were added to the stomach contents. Eight-hour contents incubation was conducted in special vessels located in an automatic water bath with a temperature of 39 ºC, during which samples for gas, ammonia, pH analysis were taken. The most frequently isolated bacteria was Escherichia coli which was found in smear tests from ileum in 95,8% and from caecal in 83,3% of the examined rats. Bacillus sp. was largely isolated from caecal (95,8%) quantities. Bacillus sp. was largely isolated from caecal (95,8%). The conducted experiments indicated that ammonia contents is higher in caecal than in stomach. Substantial differences connected to sex are also exhibited. The same case is with the lactic acid level. The pH level is lower in stomach (3,8 to 4,1), and in caecal it is 6,8.

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