The intestinal microflora of shrimp is sick

In recent years, the disease situation on shrimp has been increasing more and more due to erratic weather, shrimp often suffer from diseases such as white spots, hepatopancreatic necrosis, red body, scurvy and white feces. hard on the farmers' economy.
 
Shrimp disease
In the world, a number of studies have been conducted on the intestinal bacteria system of whiteleg shrimp. Bacterial composition has been elucidated by several research groups (Qiao et al., 2017; Suo et al., 2017) including changes in bacterial composition in shrimp gut through growth stages ( Huang et al., 2014) and comparison of bacterial composition between diseased and normal shrimp intestinal samples (Yang et al., 2016). The results of the studies have shown the fluctuation and change in the order of dominant groups.
The gut microbiota is a complex ecosystem with many functions for the host. The stability of the intestinal microflora affects the growth and health of the immune system. Conversely, during the development of the host, the intestinal flora is also influenced by the structure change in composition and the degree of diversity with the host's age (Fraune, Bosch, 2010; Li et al., 2017). Therefore, an effort to explore the composition and diversity of intestinal flora is necessary to understand the relationship as well as the interaction between the intestinal flora and health, growth. as well as in different stages of host development.
In addition, many methods have been applied in the study of the composition of the bacterial system such as molecular flow library and electrophoresis electrophoresis method (PCR-DGGE). However, these methods have shown weaknesses in the ability to assess the overall composition of a bacterial system. On that basis, a new generation sequencing method has been developed to overcome the disadvantages of the traditional method of simultaneous study of complex bacterial systems based on the 16S rRNA genome (Glenn, 2011; Sun et al., 2014).
This study was conducted to evaluate the bacterial composition in the intestine of three-month white shrimp between diseased shrimp farms, poorly grown shrimp ponds and healthy shrimp ponds. The results of this study will help to predict a number of potential pathogens in vannamei.
Samples of vannamei farmed in semi-intensive ponds, which were samples from 3 3-month-old ponds collected at Lich Hoi Thuong commune (Tran De district, Soc Trang province) in November 2015 include: diseases of unknown cause (ST4), poorly grown shrimp ponds (ST3), and healthy shrimp farms (ST1)
From the result of comparing the 16S rRNA gene sequence of shrimp intestinal samples collected in vannamei shrimp ponds (Litopenaeus vannamei) and the control group is a sample of intestinal shrimp collected in black tiger shrimp farm (Penaeus monodon) (ST) -PM) and a muscle tissue sample of vannamei (muscle tissue) with the database bank (16S rRNA) Green genes, the bacterial composition in the intestines of vannamei shrimp farms .
Through the analysis results showed the composition and diversity of bacteria in the intestine of vannamei between three vannamei shrimp farms after 3 months of culture. Dominant sectors include Proteobacteria (49.3–57.4%), Firmicutes (15.6–34.4%), Bacteroidetes (0.1–16.9%) of all industries. in the samples of vannamei intestines studied. Rhizobium (0.4–26.1%), Vibrio (0–22.3%), Spongiimonas (0–16.7%) are the dominant genera among the genera in the research samples. The study also showed that, at an industry level, Fusobacterium (10%) was classified as a pathogen that was found primarily in shrimp intestinal samples in infected white shrimp farms (ST4) compared to with two samples of vannamei in vannamei poorly grown (ST3) (0%) and vannamei vannamei grow normally (ST1) (0.6%).
The analytical results also contribute to predicting the presence of potentially pathogenic pathogens in shrimp in samples of diseased shrimp intestines (ST4) including: Fusobacterium, Vibrio genus.
These results indicate that the bacterial flora in diseased shrimp samples has lost the balance between the beneficial bacteria group and the harmful bacteria group. The presence of more pathogenic bacteria is considered to be related to disease and mortality in shrimp. This conclusion is consistent with the results of Venn diagram analysis and correlation analysis of samples through PCA chart between ST4 disease samples and the remaining samples.
Updated on March 27, 2020

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