Bacterial Diversity Of Duck Fish Farming Systems Research

A small ecosystem was composed of ducks, fish, water and soil of living area, which play an important role not only in material circulations of pond and disease occurrence, but also in aspects of the growth, nutrition and immunity of ducks or fish. This experiment is to study on bacterial community structure of ducks and fish intestinal contents, water and soil of living area, then to know the influence and the relationship among ducks, fish and living area.The sanitation bacteria in environment and intestinal contents were isolated and then counted by the traditional pure culture methods. The results showed the number of viable bacteria in water had obvious seasonal change. The number of viable bacteria was higher in the summer than the spring. And the number of viable bacteria was higher in the duck living water than that of the fish living water, no matter what the seasons and bacterial species. The number of viable bacteria, MPN and Streptococcus were lower in the fish living soil than in the duck living soil, but the number of Salmonella was contrary to them no matter what seasons. There was no significantly change in the number of MPN and Streptococcus with the season, but the growth of viable bacteria was 10 times higher in duck intestinal contents. While the number of viable bacteria in fish intestinal contents had a greatly change with the season, especially the number of Streptococcus and Salmonella were significantly lower in the summer, and the reason may be related to the temperature of fish living water.The conventional method of phenol-chloroform could successfully extract DNA from the water of living area, and the method of extracting DNA from the intestinal contents was the modified method of CTAB. After DNA extraction, the DNA was used as template to amplify 16SrDNA gene with universal primers. Then amplification products were separated directly by DGGE. Results indicated that bacterial community structure in this ecosystem could be analyzed by PCR-DGGE. From the DGGE profile, it showed the living area of water and intestinal bacterial diversity, and the bands were different in several number, location and brightness by reason of the difference individuals and sampling sites. The similar bands of water samples were obvious found from DGGE profile, which could be considered the bacterial community structure of the same environment was similar though water samples were collected from different locations, and there were some common bacteria. The profile of ducks and fish intestinal bacterial indicated the bands were different in the number and brightness because of individual differences. Although some bands of intestinal bacterial were similar in profile, there was significantly distinction in main bands. The dominant intestinal bacteria were different with individual difference, which may be related to the feeding patterns, the feed supply and the growth conditions.