Microbiome analysis of Litopenaeus vannamei reveals Vibrio as main risk factor of white faeces syndrome

Screening of intestinal protein signatures in pacific white-leg shrimp (Litopenaeus vannamei) with white feces syndrome by proteome

White feces syndrome (WFS) has been one of the emerging diseases causing instructive economic losses in the penaeid shrimp aquaculture industry, though the etiology of WFS remains unclear. In this research, we have collected intestinal samples from normal and diseased shrimp (Litopenaeus vannamei) from the natural shrimp cultivation farm for histological and proteomic analysis. The preliminary pathogen detection confirmed that WFS in this study was (Enterocytozoon hepatopenaei) EHP-WFS that was related to Vibrio spp. Moreover, the destructive damage of the intestine in WFS-diseased shrimp revealed by histological observation indicated a deficiency in digestive capacity, which might be closely related to WFS. Furthermore, we have characterized 86 and 165 differentially expressed proteins (DEPs) through a non-directional integrative analysis, which were significantly up-regulated and down-regulated, respectively. The down-regulation of various digestive enzymes in the WFS-diseased shrimp was consistent with the results of intestinal histology. DEPs were enriched in the lysosome and sphingolipid metabolism pathway, indicating that they were strongly associated with the occurrence of WFS (P < 0.05). Of this, the expression of down-regulated proteins in the lysosomal pathway was further validated by real-time quantitative polymerase chain reaction (RT-qPCR). Ultimately, crustin, lipase, and glucosylceramidase (GBA), which were significantly decreased in WFS-diseased shrimp, were screened as the predictive protein signatures for the diagnosis and prevention of WFS. Consequently, our results will provide a theoretical reference for the diagnosis of EHP-WFS by the protein aspect and crustin, lipase, and GBA may be predictive signatures that are suitable for EHP-WFS.

Gut microbiota and functional metabolic predictions in white feces disease-infected Pacific white shrimp, Penaeus vannamei, from Indonesian farms

The etiological agent of white feces disease (WFD) infecting Pacific white shrimp Penaeus vannamei in Indonesia farms remains obscure. The present study aimed to identify possible causative agents of WFD infection in Pacific white shrimps cultured in Indonesian farms. WFD-infected and healthy samples (shrimp gut and rearing water) were collected from 8 commercial shrimp farms in East Java, Indonesia followed by bacterial community profiling using HiSeq sequencing of 16S rRNA gene amplicons. The results showed that the microbiota composition in the guts of WFD-infected shrimps was significantly different (p < 0.05) from the guts of healthy shrimps in term of genus and bacterial species. The intestinal bacterial communities of WFS-infected shrimps were overrepresented by Vibrio coralliilyticus, whereas Paracoccus was underrepresented. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States functional predictions indicated that relative abundances of 12 genes associated with the pathogenicity of bacteria including amino acid metabolisms, carbohydrate metabolisms, glycan biosynthesis, and xenobiotic biodegradation and metabolism were significantly (p < 0.05) higher in the gut microbiota of WFD-infected shrimps. These findings provide insights into the microbiome domination and their metabolic activities in the digestive tract of WFD-infected shrimps and suggest that V. coralliilyticus is a possible causative agent of WFD in cultured Indonesia Pacific white shrimp.

White feces syndrome in shrimp: Comprehensive understanding of immune system responses

White feces syndrome (WFS) is a multifactorial disease that affects global shrimp production. The diagnostic approach to identify WFS involves traditional and molecular scientific methods by examining histopathology, bioassays, PCR (polymerase chain reaction), and calorimetric estimation. The pathogenesis of WFS is closely associated with Vibrio spp., intestinal microbiota (IM) dysbiosis, and Enterocytozoon hepatopenaei (EHP). It also has caused over 10-15 % loss in the aquaculture industry and is also known to cause retardation, lethargy and slowly leading to high mortality in shrimp farms. Therefore, it is necessary to understand the molecular mechanisms processed under the association of IM dysbiosis, Vibrio spp., and EHP to analyze the impact of disease on the innate immune system of shrimp. However, only very few reviews have described the molecular pathways involved in WFS. Hence, this review aims to elucidate an in-depth analysis of molecular pathways involved in the innate immune system of shrimp and their response to pathogens. The analysis and understanding of the impact of shrimp's innate immune system on WFS would help in developing treatments to prevent the spread of disease, thereby improving the economic condition of shrimp farms worldwide.

Expanding germ-organ theory: Understanding non-communicable diseases through enterobacterial translocation

Diverse microbial communities colonize different habitats of the human body, including gut, oral cavity, nasal cavity and tissues. These microbial communities are known as human microbiome, plays a vital role in maintaining the health. However, changes in the composition and functions of human microbiome can result in chronic low-grade inflammation, which can damage the epithelial cells and allows pathogens and their toxic metabolites to translocate into other organs such as the liver, heart, and kidneys, causing metabolic inflammation. This dysbiosis of human microbiome has been directly linked to the onset of several non-communicable diseases. Recent metabolomics studies have revealed that pathogens produce several uraemic toxins. These metabolites can serve as inter-kingdom signals, entering the circulatory system and altering host metabolism, thereby aggravating a variety of diseases. Interestingly, Enterobacteriaceae, a critical member of Proteobacteria, has been commonly associated with several non-communicable diseases, and the abundance of this family has been positively correlated with uraemic toxin production. Hence, this review provides a comprehensive overview of Enterobacterial translocation and their metabolites role in non-communicable diseases. This understanding may lead to the identification of novel biomarkers for each metabolic disease as well as the development of novel therapeutic drugs.