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Abstract The polyculture model embracing poultry-fish farming is a conventional and crucial culture model of tilapia universally. Because of the risk of pathogenic bacteria passing from livestock to fish along the aquaculture and food chains, the model is considered to be harmful to the healthy cultivation of tilapia, but no theoretical basis has been presented. Samples including tilapia gill, goose feces, pond water and bottom sediment from a goose-fish farm were collected five times continuously, and the microflora structure and diversity were detected by high-throughput sequencing. The results showed that an average of 22 phyla with 169 genera, 27 phyla with 176 genera, and 38 phyla with 206 genera, were identified in tilapia gill, goose feces and pond water, respectively. The highest bacterial diversity was found in bottom sediment with 60 phyla with 205 genera (Shannon index 6.64) . At the phylum level, bacteria composition in tilapia gill, bottom sediment and pond water was more stable than that in goose feces, and the dominant bacteria were Firmicutes, Proteobacteria, Bacteroidetes, and Cyanobacteria in turn. At the genus level, no common pathogenic bacteria have been found in both goose feces and tilapia gills. However, it was noteworthy that some pathogenic bacteria such as Acinetobacter, Fusobacterium, Clostridium, and Campylobacter have been identified in goose feces. Several beneficial bacteria such as Lactobacillus, Geobacillus, and Bacillus were abundant in tilapia gills, compared with that of pathogenic bacteria, including Pseudomonas and Streptococcus. Most of the identified bacteria in bottom sediment were anaerobes, such as Dechloromonas, Anaeromyxobacter, and Geobacter which mainly participates in bioremediation. The β-diversity analysis also revealed the bacterial compositions had less similarity between different sources of samples. Above all, the bacterial composition of samples from different sources in the polyculture model differs greatly at the genus level. No direct proof supports the pathogenic bacteria were transported from goose to tilapia.
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Received: 18 September 2020
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2019, Vol. 32 
