Vestnik MGTU (Sep 2019)
Comprehensive monitoring of the bacterial plankton fish farm of the Tuloma River and the intestinal enteric microbiota cultivated in trout cages
Abstract
This paper deals with the field of protection and management of aquaculture growing technologies. The comprehensive monitoring of the microbiological parameters of the aquatic environment of the Tuloma River and the observation of fluctuations in the microbial communities of rainbow trout cultivated in cages (Parasalmo mykiss) has been presented. Based on researching patterns of distribution of heterotrophic bacterial plankton in the water of the cage farm of the Tuloma River, the trophic state index has been determined, the value of which increases in the spring-summer season and has a significant correlation with water temperature (the coefficient is 0.7). The analysis of seasonal dynamics of the ratio of autochthonous and allochthonous microbiota of water within the cage area has been given; the results indicate the suppression of water self-purification process in the spring-summer season and ending in winter. In spring the appearance of bacteria of the intestinal group, in the amount allowed by regulatory documentation, indicates sanitary assessment of water. A method of scraping mucous from the given area of the rainbow trout intestinal surface has been developed to calculate the seed material; it allows a comparative analysis of the numerical characteristics of the enteric microbiota of both the mucosa and the intestinal contents of the studied object. As a result of applying this method, it has been found that the number of bacteria in the intestinal mucosa of trout varies in a wide range, the maximum number of which is two times lower than that in the hydrobiont chyme, and its seasonal dynamics repeat the pattern of seasonal changes in bacterial plankton quantitative indicators. Studying the qualitative characteristics of the microbiota of water and fish, the dominant role of representatives of the genus Pseudomonas in the spring period, both in the water and in the composition of the microbiocenosis of fish, has been determined. Together with bacteria of the intestinal group, being conditionally pathogenic and able to infect weakened fish, these microorganisms can act as bioindicators of water pollution. The results can be used to develop technologies to fight infectious and invasive diseases of fish, to control the quality of hydrobionts and to ensure the environmental safety of fisheries reservoirs.
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