Research On The Ecological Balance Of The Normal Flora In The Digestive Tract Of Chickens

With the wide spread application of the various antibiotics, the microecology disorder is prevailing in the animals. This phenomenon not only poses the difficulty to deal with the infection with the double infection and * location transfer, but increases the drug-resistant bacteria and the quantity of antibiotics in the animal product, therefore induces serious public health problems. The main symptom of the microecology is the changes of the Normal Flora, so the ecological balance of the Normal Flora at different locations of the animal could be regarded as the physical index to assess the animal heath, which could be used in the field of the veterinary and animal breeding. In this study, the microecological methods were applied to study the Location, Quantitative and Qualitative of the Normal Flora of the chickens of different ages, different breeding environments and different health situations. The physiological values of the Normal Flora in the digestive tract of chickens were identified, and the values enriched the contents of the microecology, provided theoretical bases for the chickens' digestive tract microecological kinetics and offered new thoughts and methods to deal with chickens' diarrhea, Coccidiosis etc. from the viewpoints of Microecology.The following four parts were included in the studies:Part Ⅰ The studies on the location law of the Normal Flora in the digestive tract of chickensThe 9 Normal Flora (Clostridium, Eubacterium, Peptococcus, Bifido-bacterium, Lactobacillus, Bacteroides, Enterococcus, Staphylococcus, Escherichia coli) in the 5 locations of chickens' digestive tract (Crop, Proventriculus, Ileum, Cecum and Rectum) from 1 to 40 days were isolated, cultured ,identified and accounted , thus illustrated the physical values and theprocess of the location of the Normal Flora. When 1 -day-old, all the studied bacteria except for Bacteroides could locate in the digestive tract of chickens, the aerobes and facultative anaerobes obviously outnumbered the anaerobes. The number of all the Normal Fiora increases drastically from 1 to 4 days old, while the increasing speed is mild after 4 days old. The Bacteroides could present in the Rectum and Cecum after 1 -day-old, in Ileum after 3-day-old, while in Crop and Proventriculus until after 5-day-old. The above illustrats that the Bacteroides firstly locates in the hindigestive tract, then locates in the foredigestive tract.Part II: The comparison of the Normal Flora in digestive tract of the SPF chickens with that of the ordinary chickensIn this part, Qualitative and quantative investigation was carried out on the intestinal bacterial community in 5 parts of the digestive tract of SPF and ordinary chickens (52 days old). 9 kinds of the intestinal bacteria were selected and counted on various selective media. The results show that the numbers of Eubacterium, Bifidobacterium, Bacteroides and Escherichia coli in the Crop of SPF chickens is higher than that of the ordinary ones, and there is significant distinctive statistic discrepancy in Eubacterium (P<0.01); the numbers of Eubacterium, Peptococcus, Bifidobacterium, Lactobacillus, Bacteroides and Escherichia coli in the Proventriculus of SPF are higher than that of the ordinary ones, and there is distinctive statistic discrepancy in Eubacterium (P<0.05); the numbers of Eubacterium,Bifidobacterium, Bacteroides , Staphylococcus and Escherichia coli in the Ileum of SPF chickens are higher than that of the ordinary ones, and there is significant distinctive statistic discrepancy in Bacteroides (P<0.01); the numbers of Clositridium, Peptococcus, Bifidobacterium, Lactobacillus, Enterococcus in the Cecum of SPF chickens are lower than that of the ordinary ones ,and there is distinctive statistic discrepancy in Lactobacillus(P<0.05); the numbers of all the bacteria in the Rectum of SPF chickens are lower than that of the ordinaryones ,and there is distinctive statistic discrepancy in Bifidobacterium and Lactobacillus (P<0.05).Part HI The comparison of the number of Lactobacillus in the Crop of diarrhea chickens with that of the health chickens and the observation of the super microstructure of the epithelia exterior of the CropThe bacteria accounting was made about the Lactobacillus in the Crop of the diarrhea and health chickens(50 days old), and observe the super ? microstructure of the bacterium embedded in the epithelia of the Crop with the Scanning Electron Microscope. The results show that the number of the Lactobacillus in the Crop of the diarrhea chickens is 8.66 ± 0.5,and it is lower than that in the health chickens, which was 9.44±0.3. There is significant distinctive statistic discrepancy (P<0.01). Through the Scanning Electron Microscope, it is identified that there are amounts of short bacilus in the surface of the Crop epithelia of health chickens, which are densely ranged and vertical with the epithelia. Some of them are imbedded in the epithelia, thus forming the velum flora. Contrary to the above, the number of short bacilus in the surface of Crop mucus of the diarrhea chickens is lower and arranged loosely and unorderly.there are some cocci also.Part IV: The effects of coccidium infection on the Normal Flora in the Rectum of ChicklingIn this part, the Quantitative and Qualitative analysis about 8 kinds of the normal flora in rectum of coccidium infected artifically chicklings and health chicklings, which are Clostridium, Eubacterium, Peptococcus, Lactobacillus, Bacteroides, Enterococcus, Staphylococcus and Escherichia coli, were made. The results show that the numbers of Clostridium(P<0.01), Staphylococcus (P<0.05) and Escherichia coli (P<0.01) in the rectum of the artificially infected chicklings are higher than the health values, and the numbers of Eubacterium(P<0.05), Peptococcus(P<0.05), Lactobacillus(P<0.01) and Enterococcus (P<0.05 ) are lower compared with the health values at the 6thday of being infected. At the 8th day of being infected, the number of Clostridium(P<0.05) is still higher than the health values, and the numbers of Peptococcus(P<0.01), Lactobacillus(P<0.05) and Enterococcus (P<0.01 ) are lower compared with the healthl values. At 13th day of being infected , the numbers of Clostridium(P<0.05) and Escherichia coli( P<0.05 )are higher than the health values, and the numbers of Peptococcus(P<0.05), Lacto bacillus(P<0.01) and Enterococcus (P<0.05 ) are lower than the health values. At the 20th day of being infected, the numbers of Clostridium (P<0.05j and_ Staphylococcus (P<0.01) are higher than the health values, and the number of Lactobacillus (P<0.01) remains lower than the health values.