The mTOR/PGC-1α/SIRT3 Pathway Drives Reductive Glutamine Metabolism to Reduce Oxidative Stress Caused by ISKNV in CPB Cells

Infectious spleen and kidney necrosis virus (ISKNV) is the causative agent of farmed fish disease that has caused huge economic losses in fresh and marine fish aquaculture. The redox state of cells is shaped by virus into a favorable microenvironment for virus replication and proliferation.

Genomic Perspectives on Aeromonas salmonicida subsp. salmonicida Strain 890054 as a Model System for Pathogenicity Studies and Mitigation of Fish Infections

Aeromonas salmonicida subsp. salmonicida is a Gram-negative bacterium that causes furunculosis, a fish disease claiming substantial economic losses in the aquaculture industry. Major challenges exist in monitoring and controlling fish infections in aquaculture farms. Development of management practices to improve the sustainability of fish farming with disease prevention necessitates studies using well-defined systems and well-characterized bacterial isolates. Even though several A. salmonicida subsp. salmonicida genomes have been completely assembled and thoroughly annotated, in vivo pathogenicity data are lacking. Here we present A. salmonicida subsp. salmonicida 890054 as a prototype strain for standardized furunculosis challenges with survival data. Computational analysis of sequencing results provided a complete circular genome with annotations of plasmids carrying virulence factors, antimicrobial resistance, and secondary metabolite coding genes. The analysis also revealed the presence of an IncU plasmid distinct from other IncU plasmids previously associated with Aeromonas.

Omics Strategies in Current Advancements of Infectious Fish Disease Management

Aquaculture is an important industry globally as it remains one of the significant alternatives of animal protein source supplies for humankind. Yet, the progression of this industry is being dampened by the increasing rate of fish mortality, mainly the outbreak of infectious diseases. Consequently, the regress in aquaculture ultimately results in the economy of multiple countries being affected due to the decline of product yields and marketability. By 2025, aquaculture is expected to contribute approximately 57% of fish consumption worldwide. Without a strategic approach to curb infectious diseases, the increasing demands of the aquaculture industry may not be sustainable and hence contributing to the over-fishing of wild fish. Recently, a new holistic approach that utilizes multi-omics platforms including transcriptomics, proteomics, and metabolomics is unraveling the intricate molecular mechanisms of host-pathogen interaction. This approach aims to provide a better understanding of how to improve the resistance of host species. However, no comprehensive review has been published on multi-omics strategies in deciphering fish disease etiology and molecular regulation. Most publications have only covered particular omics and no constructive reviews on various omics findings across fish species, particularly on their immune systems, have been described elsewhere. Our previous publication reviewed the integration of omics application for understanding the mechanism of fish immune response due to microbial infection. Hence, this review provides a thorough compilation of current advancements in omics strategies for fish disease management in the aquaculture industry. The discovery of biomarkers in various fish diseases and their potential advancement to complement the recent progress in combatting fish disease is also discussed in this review.

Comparative Analysis of Intestinal Bacterial Communities in Healthy and Diseased Nibea albiflora

Background: The gut microbiota is an integral part of the host and plays an important role in both growth and development of host. The research on intestinal microbiota of Nibea albiflora and its relationship to fish disease have not been reported before. This study aimed to investigate the composition and differences of gut bacteria between healthy and diseased Nibea albiflora. Methods: The intestines were collected from forty fish (twenty healthy fish and twenty diseased). Total DNA was extracted and then amplified by nested PCR. The PCR product was subjected to the DGGE test and performed at the IlluminaMiseq sequencing. Result: The obtained results of both utilized techniques (DGGE and Next generation sequencing) showed that dominant bacteria could be grouped into four populations and the composition of intestinal bacteria differed significantly between healthy (NH) and diseased (ND) Nibea albiflora. NH has higher levels of γ-Proteobacteria and Firmicutes and with 46.91% Photobacterium supplied the dominant genus in NH. Fusobacteria and Bacteroidetes were higher in ND and Cetobacterium occupied 62.31% and was the dominant genus in ND. More probiotics were detected in NH, such as Lactobacillus, Brevibacillus, Enterococcus and Lactococcus (occupying 1.77% -19.76%), while less than 0.2% were detected for both in ND. More genera that belonged to Vibrionaceae, such as Enterovibrio (9.27%) and Vibrio (2.17%), were detected in ND and their abundances in NH were 0.79% and 0.03%, respectively.

Fish disease study of Asian seabass (Lates calcarifer) in a floating marine cage: Endoparasite and blood profile

Hidayati D, Nurindra AR, Abdulgani N, Setiawan E, Maulidina N, Syahroni N, Mulyadi Y. 2021. Fish disease study of Asian seabass (Lates calcarifer) in a floating marine cage: Endoparasite and blood profile. Biodiversitas 22: 4505-4511. The Indonesian government has multiple targets and priority programs to increase aquaculture productivity in 2021. Hence, the development of mariculture commodities such as Asian seabass (Lates calcarifer) in one of the potential coastal areas, Sendang Biru, is strategic. However, sustainable productivity needs good management, including the health monitoring of fish. This study aimed to determine the condition of seabass under mariculture in a floating cage in Sendang Biru, Malang, Indonesia. Thirty seabass (Lates calcarifer) from 0 to 60 days after stocking age (ASE) were taken from a Sendang Biru floating cage. Blood and intestine samples were taken five times from day 0 to day 60 ASE. Blood samples were carried out through the caudal vein and observed using a hemocytometer. Endoparasite analysis was performed by fish intestine examination from the anterior intestine to the posterior rectum. Pseudoterranova and Diphyllobothrium were found with 10% and 3.33% prevalence, respectively. The intensity of Pseudoterranova was one individual/fish, and that of Diphyllobothrium was 2.33 individuals/fish. The highest mean of total erythrocyte count (TEC) found in 0 day ASE was at the level of 0.82±0.55×106 cells/mm3, and the lowest was found in 60 days ASE (0.51±0.24×106 cells/mm3). The highest mean of total leucocyte count (TLC) was 9.20±3.69x104 cells/mm3, at day 0, and leukocyte levels tended to decrease until day 60 ASE (7.74±3.43×104 cells/mm3). Overall, despite the TEC and TLC tending to decrease from 0 to 60 days ASE, in statistically indicated no significant differences in TLC at different ASEs (p > 0.05). The hematological profile indicated the health statuses of the cultured Asian seabass in the current study were in a condition of anemic and infected.

Potential Application of PCR Based Molecular Methods in Fish Pathogen Identification: A Review

Molecular biology developments have led to fast growth in new methods for fish disease diagnosis. Molecular diagnostic methods are rapid and more specific, more sensitive than the culture of pathogens, serology, histology, and biochemical methods which are traditionally utilized to identify causative agent fish disease. Molecular diagnostic methods are valuable for detecting specific pathogens that are difficult to culture in vitro or require a long cultivation period and it significantly more rapid in providing results compared to culture. It enables earlier informed decision-making and rapid diagnosis of bacteremia, particularly for low levels of bacteria in specimens. Molecular techniques which have the major significance are mainly PCR-based molecular diagnostic methods including Polymerase Chain Reaction (PCR), Real-Time Polymerase Chain Reaction (RT-PCR), Multiplex Polymerase Chain Reaction (multiplexPCR), and Random Amplified Polymorphic DNA (RAPD). These have been increasingly utilized to diagnose fish disease for the last recent years. Molecular diagnostic methods can detect pathogens from asymptomatic fish, so disease outbreaks could be prevented. As a consequence, antibiotic treatment can be reduced and the development of antibiotic-resistant bacteria can be eliminated. In this review paper, we attempt to summarize the potentiality of PCR-based molecular diagnostic methods and their application in fish pathogen identification.

Epizootic Ulcerative Syndrome (EUS) Fish Disease Chronology, Status and Major Outbreaks in the World

Epizootic Ulcerative Syndrome (EUS) has been causing large-scale mortality among the freshwater fishes of the globe since the 1070s. The symptoms include large haemorrhagic cutaneous ulcers, epidermal degeneration and necrosis followed by sloughing of scales. There have been many studies on EUS throughout the world. In India, since the initiation of EUS, in 1988, our study tried to reveal the aetiology of the disease through extensive and intensive studies on different aspects, like limnological, physical, chemical, bacteriological, fungal, viral including electron microscopic studies. Details of EUS investigation has been discussed in the present paper.