Genome sequence of white spot syndrome virus (WSSV) infecting cultured black tiger shrimp (Penaeus monodon) in Bangladesh.

The white spot syndrome virus (WSSV) is a causative agent of white spot disease (WSD) in crustaceans, especially in cultivated black tiger shrimp (Penaeus monodon), leading to significant economic losses in the aquaculture sector. The present study describes four whole genome sequences of WSSV obtained from coastal regions of Bangladesh.

Microbiome pattern and diversity of an anadromous fish, hilsa shad (Tenualosa ilisha).

BACKGROUND: The host-microbe interactions are complex, dynamic and context-dependent. In this regard, migratory fish species like hilsa shad (Tenualosa ilisha), which migrates from seawater to freshwater for spawning, provides a unique system for investigating the microbiome under an additional change in fish's habitat. This work was undertaken to detect taxonomic variation of microbiome and their function in the migration of hilsa. METHODS AND RESULTS: The study employed 16S rRNA amplicon-based metagenomic analysis to scrutinize bacterial diversity in hilsa gut, skin mucus and water. Thus, a total of 284 operational taxonomic units (OTUs), 9 phyla, 35 orders and 121 genera were identified in all samples. More than 60% of the identified bacteria were Proteobacteria with modest abundance (> 5%) of Firmicutes, Bacteroidetes and Actinobacteria. Leucobacter in gut and Serratia in skin mucus were the core bacterial genera, while Acinetobacter, Pseudomonas and Psychrobacter exhibited differential compositions in gut, skin mucus and water. CONCLUSIONS: Representative fresh-, brackish- and seawater samples of hilsa habitats were primarily composed of Vibrio, Serratia and Psychrobacter, and their diversity in seawater was significantly higher (P < 0.05) than freshwater. Overall, salinity and water microbiota had an influence on the microbial composition of hilsa shad, contributing to host metabolism and adaptation processes. This pioneer exploration of hilsa gut and skin mucus bacteria across habitats will advance our insights into microbiome assembly in migratory fish populations.

Two new records and an updated checklist of freshwater crabs (Arthropoda, Malacostraca, Decapoda, Potamidae and Gecarcinucidae) from Bangladesh.

The species diversity of freshwater crabs of Bangladesh is poorly known. In this study, Acanthopotamonfungosum (Alcock, 1909) and Maydelliathelphusaedentula (Alcock, 1909) are reported as new records from Bangladesh. The two species were identified through morphology and molecular phylogeny based on 16S rDNA gene sequences. Herein, diagnostic characters of both species are provided respective to close congeners. There is concern over the conservation status of A.fungosum due to its narrow distributional range. In addition, an updated checklist and a key to the freshwater crabs of Bangladesh are provided.

Assessment of benthic macroinvertebrates as potential bioindicators of anthropogenic disturbance in southeast Bangladesh coast.

Many human activities can greatly influence and alter the health of aquatic ecosystems. In this regard, the quantitative analysis of macroinvertebrates and their relationships with ecological variables is an effective method in environmental monitoring programs. Here, we used the benthic macroinvertebrate community as bioindicators for assessing anthropogenic impacts on coastal waters in southeast Bangladesh. Sediment samples were collected seasonally from three different sites influenced either by mangrove forests, aquaculture activity or sewage input. The indicator value index (IndVal) analysis revealed 23 species of benthic macroinvertebrates as potential bioindicators namely Enigmonia aenigmatica, Mactra chinensis and Pharella javanica of the class Bivalvia; Tubifex tubifex of the class Clitellata; Lithopoma brevispina, Bullia vittata, Pomacea maculata and Umbonium vestiarium of the class Gastropoda; Gammarus roeselii of the class Malacostraca; and Amphicteis gunneri, Amphitrite ornata, Aricidea simplex, Cirratulus cirratus, Heterospio catalinensis, Hypereteone foliosa, Lopadorrhynchus henseni, Neanthes chingrighattensis, Micronephthys oligobranchia, Nephtys hombergii, Nereis jacksoni, Nereis zonata, Polyodontes maxillosus and Stygocapitella subterranean of the class Polychaeta. Their composition across three sites varied significantly (P < 0.05) due to influence of environmental conditions as inferred from redundancy analysis. Polychaeta, Gastropoda and Malacostraca were susceptible to sewage input, while Bivalvia and Clitellata were susceptible to aquaculture effluent. The results of this baseline study suggest that the identified benthic macroinvertebrate species can potentially be used to monitor anthropogenic disturbances in the marine environment.

Single and Multi-Strain Probiotics Supplementation in Commercially Prominent Finfish Aquaculture: Review of the Current Knowledge.

The Nile tilapia Oreochromis niloticus, Atlantic salmon Salmo salar, rainbow trout Oncorhynchus mykiss, olive flounder Paralichthys olivaceus, common carp Cyprinus carpio, grass carp Ctenopharyngodon idella and rohu carp Labeo rohita are farmed commercially worldwide. Production of these important finfishes is rapidly expanding, and intensive culture practices can lead to stress in fish, often reducing resistance to infectious diseases. Antibiotics and other drugs are routinely used for the treatment of diseases and sometimes applied preventatively to combat microbial pathogens. This strategy is responsible for the emergence and spread of antimicrobial resistance, mass killing of environmental/beneficial bacteria, and residual effects in humans. As an alternative, the administration of probiotics has gained acceptance for disease control in aquaculture. Probiotics have been found to improve growth, feed utilization, immunological status, disease resistance, and to promote transcriptomic profiles and internal microbial balance of host organisms. The present review discusses the effects of single and multi-strain probiotics on growth, immunity, heamato-biochemical parameters, and disease resistance of the above-mentioned finfishes. The application and outcome of probiotics in the field or open pond system, gaps in existing knowledge, and issues worthy of further research are also highlighted.

Transcriptomic response of intertidal brittle star Ophiothrix exigua to seasonal variation.

Adaptation to seasonal change is essential for survival, and is especially critical for organisms living in physically harsh environments. Brittle stars (Ophiothrix), known as a keystone species, inhabiting the intertidal rocky ecosystem are affected by multiple stressors, but molecular insights into their adaptation remain poorly studied. In the present study, transcriptomic responses of Ophiothrix exigua from the intertidal habitats of the North Pacific Ocean during summer and winter are reported. A total of 12,844 differentially expressed genes (DEGs) were identified. Of these, 7102 genes were up-regulated and 5742 genes were down-regulated in summer relative to winter. One hundred fifty-two key DEGs, including 31 up-regulated and 121 down-regulated genes, were categorized into three major subcategories and seven subclasses. The key DEGs included heat shock cognate protein 70 (HSC70), toll-like receptor-2 (TLR2), cAMP-dependent protein kinase catalytic subunit beta-like isoform X2 (PKA), serine/threonine-protein kinase mTOR (MTOR), and ras-related c3 botulinum toxin substrate 1 isoform X1 (RAC1). Glutathione peroxidase-like (GPX) and tubulin superfamily members (TUBA, TUBB) were consistent across seasons. The main defense-related pathways in brittle star were phagosome, apoptosis, and glutathione metabolism. These findings would greatly enhance our understanding of the genomic basis of environmental adaptation in intertidal invertebrates.

Annotated checklist of ponyfishes (Perciformes: Leiognathidae) from Bangladesh, the northern Bay of Bengal.

Information on the taxonomy of ponyfishes (Leiognathidae Gill 1893) from Bangladesh was hitherto inadequate and details of some species were lacking. Based on specimens, the present study reports 12 species of ponyfishes from the coasts of Bangladesh with short descriptions of their diagnostic characters. Six of these species, Aurigequula longispina (Valenciennes 1835), Deveximentum megalolepis (Mochizuki & Hayashi 1989), Equulites leuciscus (Günther 1860), Eubleekeria rapsoni (Munro 1964), Gazza rhombea Kimura, Yamashita & Iwatsuki 2000 and Karalla daura (Cuvier 1829), constitute the first records in Bangladesh. The present specimens of D. megalolepis represent the westernmost distribution of this species in the Indo-Pacific region.

Antiviral peptides from aquatic organisms: Functionality and potential inhibitory effect on SARS-CoV-2.

Several antiviral peptides (AVPs) from aquatic organisms have been effective in interfering with the actions of infectious viruses, such as Human Immunodeficiency Virus-1 and Herpes Simplex Virus-1 and 2. AVPs are able to block viral attachment or entry into host cells, inhibit internal fusion or replication events by suppressing viral gene transcription, and prevent viral infections by modulating host immunity. Therefore, as promising therapeutics, the potential of aquatic AVPs for use against the COVID-19 pandemic caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) is considered. At present no therapeutic drugs are yet available. A total of 32 AVPs derived from fish and shellfish species are discussed in this review paper with notes on their properties and mechanisms of action in the inhibition of viral diseases both in humans and animals, emphasizing on SARS-CoV-2. The molecular structure of novel SARS-CoV-2 with its entry mechanisms, clinical signs and symptoms are also discussed. In spite of only a few study of these AVPs against SARS-CoV-2, aquatic AVPs properties and infection pathways (entry, replication and particle release) into coronaviruses are linked in this paper to postulate an analysis of their potential but unconfirmed actions to impair SARS-CoV-2 infection in humans.

Primary productivity connects hilsa fishery in the Bay of Bengal.

Tropical hilsa shad (Tenualosa ilisha) contributes significantly to the society and economy of Bangladesh, India and Myanmar, but little is known about their habitats across the life cycle and their relationship with environmental drivers. This study describes spatial and temporal variability of productivity in the Bay of Bengal (BoB) relating to hilsa fishery. Decadal data on net primary productivity, nutrients (i.e. nitrate, phosphate and silicate) and zooplankton were collected from Aqua MODIS, world ocean database and COPEPOD respectively with spatial resolution 1°×1°. Moreover, monthly abundance of phytoplankton, hilsa catch and long-term catch dynamics were analyzed to determine the associations between variables. The present study was extended over 3.568 million km2 area, of which 0.131-0.213 million km2 area characterized as the most productive with net primary production of >2,000 mg C/m2/day, 0.373-0.861 million km2 area as moderately productive with 500-2,000 mg C/m2/day, and 2.517-3.040 million km2 area as the least productive with <500 mg C/m2/day which were consistent with field verification data. In case of nutrients, the Ganges-Brahmaputra-Meghna (GBM) delta was rich in nitrate and phosphate than that of the Ayeyarwady delta, while silicate concentration persisted high all over the northern BoB including the deltas. A peak abundance of phytoplankton was observed in GBM delta during the months of August-November, when ~80% of total hilsa are harvested in Bangladesh annually. Variations in seasonal productivity linked with nutrients and phytoplankton abundance are important factors for predicting hilsa habitat and their migration patterns in the deltaic regions and shelf waters of BoB. These results can be useful in forecasting potential responses of the hilsa in BoB ecosystem to changing global ocean productivity.

A Revisit to the Research Updates of Drugs, Vaccines, and Bioinformatics Approaches in Combating COVID-19 Pandemic.

A new strain of coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) responsible for the coronavirus disease 2019 (COVID-19) pandemic was first detected in the city of Wuhan in Hubei province, China in late December 2019. To date, more than 1 million deaths and nearly 57 million confirmed cases have been recorded across 220 countries due to COVID-19, which is the greatest threat to global public health in our time. Although SARS-CoV-2 is genetically similar to other coronaviruses, i.e., SARS and Middle East respiratory syndrome coronavirus (MERS-CoV), no confirmed therapeutics are yet available against COVID-19, and governments, scientists, and pharmaceutical companies worldwide are working together in search for effective drugs and vaccines. Repurposing of relevant therapies, developing vaccines, and using bioinformatics to identify potential drug targets are strongly in focus to combat COVID-19. This review deals with the pathogenesis of COVID-19 and its clinical symptoms in humans including the most recent updates on candidate drugs and vaccines. Potential drugs (remdesivir, hydroxychloroquine, azithromycin, dexamethasone) and vaccines [mRNA-1273; measles, mumps and rubella (MMR), bacille Calmette-Guérin (BCG)] in human clinical trials are discussed with their composition, dosage, mode of action, and possible release dates according to the trial register of US National Library of Medicines (clinicaltrials.gov), European Union (clinicaltrialsregister.eu), and Chinese Clinical Trial Registry (chictr.org.cn) website. Moreover, recent reports on in silico approaches like molecular docking, molecular dynamics simulations, network-based identification, and homology modeling are included, toward repurposing strategies for the use of already approved drugs against newly emerged pathogens. Limitations of effectiveness, side effects, and safety issues of each approach are also highlighted. This review should be useful for the researchers working to find out an effective strategy for defeating SARS-CoV-2.

Microplastic contamination in Penaeid shrimp from the Northern Bay of Bengal.

Microplastic pollution has received increased attention recently due to potential threat to marine biota and human health. This study reports microplastic (MP) content in brown shrimp (Metapenaeus monocerous) and tiger shrimp (Penaeus monodon) inhabiting in the shallow and offshore waters of the Northern Bay of Bengal, Bangladesh. Gastrointestinal tract (GT) of shrimps (n = 150) were examined for MPs following alkali digestion, microscopic observation and chemical analysis by micro-Fourier Transformed Infrared Spectroscope (µFTIR). A total of 33 and 39 MP items were found in P. monodon and M. monocerous, averaging 3.40 ±â€¯1.23 and 3.87 ±â€¯1.05 items/g GT, respectively. Among various shapes, types and colours of MP, filament (57-58%), fiber (32-57%) and black (48-51%) were dominant amongst the various particles identified. Tiger shrimp had high numbers (23 items) of larger size fractions of MPs (1-5 mm) but brown shrimp had high numbers (15 items) of smaller MPs (250-500 µm), and µ-FTIR data confirmed 13 particles of polyamide-6 and 6 particles of rayon polymers. These results provide a baseline of MP contamination in seafood from Bangladesh that should be useful for future monitoring efforts.

Microplastics in fishes from the Northern Bay of Bengal.

Microplastics were determined in pink Bombay-duck (Harpadon nehereus), white Bombay-duck (H. translucens) and gold-stripe sardine (Sardinella gibbosa) collected from the Northern Bay of Bengal at Bangladesh. Gastrointestinal tracts of fishes (n = 25 per species) were examined for microplastics following alkali digestion protocol, microscopic observations and chemical analysis by micro-Fourier Transformed Infrared Spectroscope (µ-FTIR). A total of 443 microplastic items were found in the intestines of H. nehereus, H. translucens and S. gibbosa, averaging in the range of 3.20-8.72 items per species. Among various shapes, colours and types of microplastics, irregular (37-43%), white/transparent (26-68%) and fiber (50-55%) were dominant. The size fraction of microplastics ranging between 1 µm and 5 mm was 68-84 items/kg biomass, and µ-FTIR analysis identified 13 particles of polyethylene terephthalate and 66 particles of polyamide. The study findings raised concern that microplastics in marine fish could be a threat to public health via the food chain.

Oyster breakwater reefs promote adjacent mudflat stability and salt marsh growth in a monsoon dominated subtropical coast.

Oyster reefs have the potential as eco-engineers to improve coastal protection. A field experiment was undertaken to assess the benefit of oyster breakwater reefs to mitigate shoreline erosion in a monsoon-dominated subtropical system. Three breakwater reefs with recruited oysters were deployed on an eroding intertidal mudflat at Kutubdia Island, the southeast Bangladesh coast. Data were collected on wave dissipation by the reef structures, changes in shoreline profile, erosion-accretion patterns, and lateral saltmarsh movement and related growth. This was done over four seasons, including the rainy monsoon period. The observed wave heights in the study area ranged 0.1-0.5 m. The reefs were able to dissipate wave energy and act as breakwaters for tidal water levels between 0.5-1.0 m. Waves were totally blocked by the vertical relief of the reefs at water levels <0.5 m. On the lee side of the reefs, there was accretion of 29 cm clayey sediments with erosion reduction of 54% as compared to control sites. The changes caused by the deployed reefs also facilitated seaward expansion of the salt marsh. This study showed that breakwater oyster reefs can reduce erosion, trap suspended sediment, and support seaward saltmarsh expansion demonstrating the potential as a nature-based solution for protecting the subtropical coastlines.

Properties of Probiotics Kocuria SM1 and Rhodococcus SM2 Isolated from Fish Guts.

This study characterized probiotics Kocuria SM1 and Rhodococcus SM2, which were recovered from the intestinal microbiota of rainbow trout (Oncorhynchus mykiss, Walbaum). The cultures were Gram-positive, non-motile, catalase-positive and oxidase-negative cocci or rods. Cell multiplication of SM1 and SM2 was observed at 4-37 °C (45 °C for SM1), in 0-20% (w/v) NaCl and at pH 2-11. The viability was not affected when exposed to pepsin at pH 2.0 and 3.0, and pancreatin at pH 8.0. Neither isolates were chrome azurol S-positive for siderophore production. Of the 19 common enzymes analysed using the API-ZYM system, only 8 were evident in the culture of SM1 compared to 11 enzymes for SM2. The secondary metabolites of both probiotics were inhibitory to Acinetobacter baumannii, Vibrio anguillarum and V. ordalii; SM2 inhibited Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. SM2 was resistant to penicillin and sulphatriad, out of six antimicrobial agents; SM1 was resistant to sulphatriad. These results suggest that Kocuria SM1 and Rhodococcus SM2 are able to grow over a wide range of temperature, salinity and pH, including in conditions that mimic the gastrointestinal environment of fish and produce extracellular enzymes that may have a role in the host digestive processes. Importantly, Rhodococcus SM2 displays a high degree of bacteriocinogenic potential against multi-drug-resistant human pathogens that have never been documented among the gut microbiota of fish.

Arsenic contaminated groundwater and its treatment options in Bangladesh.

Arsenic (As) causes health concerns due to its significant toxicity and worldwide presence in drinking water and groundwater. The major sources of As pollution may be natural process such as dissolution of As-containing minerals and anthropogenic activities such as percolation of water from mines, etc. The maximum contaminant level for total As in potable water has been established as 10 µg/L. Among the countries facing As contamination problems, Bangladesh is the most affected. Up to 77 million people in Bangladesh have been exposed to toxic levels of arsenic from drinking water. Therefore, it has become an urgent need to provide As-free drinking water in rural households throughout Bangladesh. This paper provides a comprehensive overview on the recent data on arsenic contamination status, its sources and reasons of mobilization and the exposure pathways in Bangladesh. Very little literature has focused on the removal of As from groundwaters in developing countries and thus this paper aims to review the As removal technologies and be a useful resource for researchers or policy makers to help identify and investigate useful treatment options. While a number of technological developments in arsenic removal have taken place, we must consider variations in sources and quality characteristics of As polluted water and differences in the socio-economic and literacy conditions of people, and then aim at improving effectiveness in arsenic removal, reducing the cost of the system, making the technology user friendly, overcoming maintenance problems and resolving sludge management issues.

Subcellular components of probiotics Kocuria SM1 and Rhodococcus SM2 induce protective immunity in rainbow trout (Oncorhynchus mykiss, Walbaum) against Vibrio anguillarum.

The efficacy of cellular components of probiotics Kocuria SM1 and Rhodococcus SM2 to protect rainbow trout (Oncorhynchus mykiss, Walbaum) against vibriosis was assessed. Groups of fish (average weight = 10-15 g) were immunized intraperitoneally (i.p.) with 0.1 ml of subcellular materials, i.e., 0.2 ± 0.05 mg protein per fish, comprising extracellular proteins (ECPs), cell wall proteins (CWPs) and whole cell proteins (WCPs) of SM1 and SM2, respectively, or with 0.1 ml of phosphate-buffered saline (PBS) to serve as the control. Seven days after administration, fish from each group were challenged i.p. with 0.1 ml of a suspension in PBS of 3 × 10(5) cells ml(-1) per fish of Vibrio anguillarum. Use of CWPs and WCPs demonstrated significantly (P < 0.05) better protection against V. anguillarum insofar as mortalities were reduced to 11-17% [relative percent survival (RPS) = 80-87%], although ECPs fared less well (mortalities = 33-38%; RPS = 56-62%; P > 0.05), compared to 86% mortalities of the controls. The mode of action reflected activation of innate immune factors by CWPs and WCPs, demonstrating significantly (P < 0.05) increased expression of respiratory burst (optical density; OD(550 nm)) from 0.039 to 0.043-0.045, peroxidase (OD(550 nm)) from 0.26 to 0.37-0.55, and bacterial killing activities (i.e., percentage of surviving bacteria reduced from 79% to 56-57% for SM2). Moreover, an elevation of leucocyte number (from 1.93% to 1.98-2.93%; P > 0.05) and immunoglubolin level (from 27 mg ml(-1) to 28.5-33 mg ml(-1); P > 0.05) were observed with the experimental groups. These results indicate that cell components of the probiotics stimulate an immune response.

Development of protection in rainbow trout (Oncorhynchus mykiss, Walbaum) to Vibrio anguillarum following use of the probiotic Kocuria SM1.

Probiotic Kocuria SM1, which was part of the allochthonous gut microbiota of rainbow trout, was administered to rainbow trout (Oncorhynchus mykiss) fingerlings as dietary supplement at approximately 10(8) cells g(-1) for two weeks. The fish were challenged with Vibrio anguillarum and innate immunity determined over the following 5 weeks. The probiotic-fed fish survived (mortalities = 10-28%; P < 0.05) better than the controls (mortalities = 73-92%) for 5 weeks after stopping administration of Kocuria SM1, although the relative percent survival (RPS) declined steadily from 87 to 36% by the end of the experiment. A significant (P < 0.05) effect on the immune parameters was observed in fish within 3 weeks after stopping administration of Kocuria SM1 in comparison with the controls, i.e. enhancement of the respiratory burst (OD(550nm)) from 0.051 +/- 0.014 to 0.067 +/- 0.009, lysozyme 605 +/- 185 units ml(-1) to 872 +/- 114 units ml(-1), total protein 19.8 +/- 2.0 mg ml(-1) to 23.8 +/- 0.8 mg ml(-1) at 2 weeks, and leukocrit 2.9 +/- 1.8% to 5.1 +/- 1.1%, peroxidase (OD(550nm)) 0.23 +/- 0.02 to 0.37 +/- 0.11 and bacterial killing activities (percentage of surviving bacteria = 82 +/- 12% to 57 +/- 4%) at 3 weeks. Generally, the levels reduced progressively towards the end of experiment.

Kocuria SM1 controls vibriosis in rainbow trout (Oncorhynchus mykiss, Walbaum).

AIMS: To develop probiotics for the control of vibriosis caused by Vibrio anguillarum and Vibrio ordalii in finfish. METHODS AND RESULTS: Kocuria SM1, isolated from the digestive tract of rainbow trout, was administered orally to rainbow trout (Oncorhynchus mykiss) for 2 weeks at a dose equivalent to c. 10(8) cells per g of feed and then challenged intraperitoneally with V. anguillarum and V. ordalii. Use of SM1 led to a reduction in mortalities to 15-20% compared to 74-80% mortalities in the controls. SM1 stimulated both cellular and humoral immune responses in rainbow trout, by elevation of leucocytes (5.5 +/- 0.8 x 10(6) ml(-1) from 3.7 +/- 0.8 x 10(6) ml(-1)), erythrocytes (1.2 +/- 0.1 x 10(8) ml(-1) from 0.8 +/- 0.1 x 10(8) ml(-1)), protein (23 +/- 4.4 mg ml(-1) from 16 +/- 1.3 mg ml(-1)), globulin (15.7 +/- 0.2 mg ml(-1) from 9.9 +/- 0.1 mg ml(-1)) and albumin (7.3 +/- 0.2 mg ml(-1) from 6.1 +/- 0.1 mg ml(-1)) levels, upregulation of respiratory burst (0.05 +/- 0.01 from 0.02 +/- 0.01), complement (56 +/- 7.2 units ml(-1) from 40 +/- 8.0 units ml(-1)), lysozyme (920 +/- 128.8 units ml(-1) from 760 +/- 115.3 units ml(-1)) and bacterial killing activities. CONCLUSIONS: Kocuria SM1 successfully controlled vibriosis in rainbow trout, and the mode of action reflected stimulation of the host innate immune system. SIGNIFICANCE AND IMPACT OF THE STUDY: Probiotics can contribute a significant role in fish disease control strategies, and their use may replace some of the inhibitory chemicals currently used in fish farms.

Cellular components of probiotics control Yersinia ruckeri infection in rainbow trout, Oncorhynchus mykiss (Walbaum).

Subcellular components of the probiotics Aeromonas sobria GC2 and Bacillus subtilis JB-1, when administered to rainbow trout, Oncorhynchus mykiss, conferred protection against a new biogroup of Yersinia ruckeri. Thus, intraperitoneal or intramuscular injection of rainbow trout with cell wall proteins (CWPs), outer membrane proteins (OMPs), lipopolysaccharides (LPS), whole cell proteins (WCPs) and live cells followed by challenge on day 8 with Y. ruckeri led to 80-100% survival compared with 10% survival in the controls. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) profiles of WCPs and OMPs from GC2 had 10 and 5 variable protein bands in comparison to 11 and 5 bands in the WCPs and CWPs from JB-1. Proteomic analyses were employed following SDS-PAGE to categorize one dominant protein of 104.7 kDa from the CWPs of JB-1 and equated it with 'Bacillus spp. endoglucanase' with a Mascot score >69. These results point to the potential of using cellular components of probiotics for protection of fish against bacterial diseases.