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In recent years, large-scale mortalities are observed in tilapia due to infection with a novel orthomyxo-like virus named, tilapia lake virus (TiLV) which is marked to be a severe threat to universal tilapia industry. Currently, there are knowledge gaps relating to the antiviral peptide as well as there are no affordable vaccines or drugs available against TiLV yet. To understand the spreading of infection of TiLV in different organs of Oreochromis niloticus, RT-PCR analysis has been carried out. The gene segments of TiLV were retrieved from the NCBI database for computational biology analysis. The 14 functional genes were predicted from the 10 gene segments of TiLV. Phylogenetic analysis was employed to find out a better understanding for the evolution of tilapia lake virus genes. Out of 14 proteins, only six proteins show transmembrane helix region. Moreover, molecular modeling and molecular dynamics simulations of the predicted proteins revealed structural stability of the protein stabilized after 10-ns simulation. Overall, our study provided a basic bioinformatics on functional proteome of TiLV. Further, this study could be useful for development of novel peptide-based therapeutics to control TiLV infection.

Hilsa, Tenualosa ilisha, is a popular fish in northern Bay of Bengal and Hooghly-Bhagirathi river system in India. Despite the high commercial and cultural importance of the species in the region, data on its catch status and fishing effort are highly fragmentary and, sometimes, not reliable as these have not been systematically gathered. By adopting ‘Stratified Multistage Random Sampling’ method, mostly followed for marine fish catch estimation, with modifications to suit the nature of inland fish landings and migratory habit of the species, the annual catch of hilsa in Hooghly-Bhagirathi river system and associated coastal waters in northern Bay of Bengal was estimated for four consecutive years, from 2013 to 2016, as 16,318 t, 45,615 t 12,192 t and 48,922 t, respectively. The catch thus estimated was validated by comparing it with the daily catch data collected by enumerators for three months each during fishing seasons in the first two years from two locations. The catch, seasonality, CPUE and the fishing gear and crafts used were recorded. Comparison of the estimated catch of hilsa with the earlier reported catches indicated that the commercial fisheries of the fish in the Hooghly-Bhagirathi river system have seriously declined, highlighting the compelling need for conservation of the species and managing its fishery.

Human norovirus (NoV) remains the most common cause of viral gastroenteritis and the leading cause of viral foodborne outbreaks globally. NoV is highly pathogenic with an estimated median viral infective dose (ID50) ranging from 18 to 1015 genome copies. For NoV detection, the only reliable and sensitive method available for detection and quantification is reverse transcription quantitative polymerase chain reaction (RTqPCR). NoV detection in food is particularly challenging, requiring matrix specific concentration of the virus and removal of inhibitory compounds to detection assays. Hence, the RTqPCR method poses some challenges for rapid in-field or point-of-care diagnostic applications. We propose a new colorimetric NanoZyme aptasensor strategy for rapid (10 min) and ultrasensitive (calculated Limit of Detection (LoD) of 3 viruses per assay equivalent to 30 viruses/mL of sample and experimentally demonstrated LoD of 20 viruses per assay equivalent to 200 viruses/mL) detection of the infective murine norovirus (MNV), a readily cultivable surrogate for NoV. Our approach combines the enzyme-mimic catalytic activity of gold nanoparticles with high target specificity of an MNV aptamer to create sensor probes that produce a blue color in the presence of this norovirus, such that the color intensity provides the virus concentrations. Overall, our strategy offers the most sensitive detection of norovirus or a norovirus surrogate achieved to date using a biosensor approach, enabling for the first time, the detection of MNV virion corresponding to the lower end of the ID50 for NoV. We further demonstrate the robustness of the norovirus NanoZyme aptasensor by testing its performance in the presence of other nontarget microorganisms, human serum and shellfish homogenate, supporting the potential of detecting norovirus in complex matrices. This new assay format can, therefore, be of significant importance as it allows ultrasensitive norovirus detection rapidly within minutes, while also offering the simplicity of use and need for nonspecialized laboratory infrastructure.

Shrimp, as a high-protein animal food commodity, are one of the fastest growing food producing sectors in the world. It has emerged as a highly traded seafood product, currently exceeding 8 MT of high value. However, disease outbreaks, which are considered as the primary cause of production loss in shrimp farming, have moved to the forefront in recent years and brought socio-economic and environmental unsustainability to the shrimp aquaculture industry. Acute hepatopancreatic necrosis disease (AHPND), caused by Vibrio spp., is a relatively new farmed penaeid shrimp bacterial disease. The shrimp production in AHPND affected regions has dropped to ~60%, and the disease has caused a global loss of USD 43 billion to the shrimp farming industry. The conventional approaches, such as antibiotics and disinfectants, often applied for the mitigation or cure of AHPND, have had limited success. Additionally, their usage has been associated with alteration of host gut microbiota and immunity and development of antibiotic resistance in bacterial pathogens. For example, the Mexico AHPND-causing V. parahaemolyticus strain (13-306D/4 and 13-511/A1) were reported to carry tetB gene coding for tetracycline resistance gene, and V. campbellii from China was found to carry multiple antibiotic resistance genes. As a consequence, there is an urgent need to thoroughly understand the virulence mechanism of AHPND-causing Vibrio spp. and develop novel management strategies to control AHPND in shrimp aquaculture, that will be crucially important to ensure food security in the future and offer economic stability to farmers. In this review, the most important findings of AHPND are highlighted, discussed and put in perspective, and some directions for future research are presented.

Effects of the dietary therapeutic dose of oxytetracycline (OTC) at 80 mg/kg biomass/day for consecutive 10 days on the behaviour, feed intake, mortality, residue accumulation and depletion, antioxidant capacity and immune-related genes expression in juvenile Nile tilapia Oreochromis niloticus were evaluated. OTC-dosing caused mortalities, reduced feed intake, and biomass reduction at 24.5–28.5 °C. OTC residues recorded on day 10 (161.40 ± 11.10 ng/g) were within the maximum residue limits of the Codex Alimentarius. The withdrawal period was 7 days as per the European Commission's regulation. Traces of residues were present even on day 42 post-OTC-dosing. Dietary OTC reduced the antioxidant capacity of the liver and muscle tissues and down-regulated the expression of tumour necrosis factor-α, interleukin-1β, and heat shock protein-70 genes in the liver significantly during the dosing period. The data generated on the biosafety of OTC-dosing may offer inputs for the development of management strategies in maintaining fish health and food safety.

The toll-like receptor 5 (TLR5) is the most conserved important pattern recognition receptors (PRRs) often stimulated by bacterial flagellins and plays a major role in the first-line defense against invading pathogenic bacteria and in immune homeostasis. Experimental crystallographic studies have shown that the extracellular domain (ECD) of TLR5 recognizes flagellin of bacteria and functions as a homodimer in model organism zebrafish. However, no structural information is available on TLR5 functionality in the major carp Cirrhinus mrigala (mrigala) and its interaction with bacterial flagellins. Therefore, the present study was undertaken to unravel the structural basis of TLR5-flagellin recognition in mrigala using structural homodimeric TLR5-flagellin complex of zebrafish as reference. Integrative structural modeling and molecular dynamics simulations were employed to explore the structural and mechanistic details of TLR5 recognition. Results from structural snapshots of MD simulation revealed that TLR5 consistently formed close interactions with the three helices of the D1 domain in flagellin on its lateral side mediated by several conserved amino acids. Results from the intermolecular contact analysis perfectly substantiate with the findings of per residue-free energy decomposition analysis. The differential recognition mediated by flagellin to TLR5 in mrigala involves charged residues at the interface of binding as compared to the zebrafish complex. Overall our results shows TLR5 of mrigala involved in innate immunity specifically recognized a conserved site on flagellin which advocates the scientific community to explore host-specific differences in receptor activation.

In the present study, we identified salt stress tolerant genes from the marine bacterium Staphylococcus sp. strain P-TSB-70 through transcriptome sequencing. In favour of whole-genome transcriptome profiling of Staphylococcus sp. strain P-TSB-70 (GenBank Accn. No. KP117091) which tolerated upto 20% NaCl stress, the strain was cultured in the laboratory condition with 20% NaCl stress. Transcriptome analyses were performed by SOLiD4.0 sequencing technology from which 10280 and 9612 transcripts for control and treated, respectively, were obtained. The coverage per base (CPB) statistics were analyzed for both the samples. Gene ontology (GO) analysis has been categorized at varied graph levels based on three primary ontology studies viz. cellular components, biological processes, and molecular functions. The KEGG analysis of the assembled transcripts using KAAS showed presumed components of metabolic pathways which perhaps implicated in diverse metabolic pathways responsible for salt tolerance viz. glycolysis/gluconeogenesis, oxidative phosphorylation, glutathione metabolism, etc. further involving in salt tolerance. Overall, 90 salt stress tolerant genes were identified as of 186 salt-related transcripts. Several genes have been found executing normally in the TCA cycle pathway, integral membrane proteins, generation of the osmoprotectants, enzymatic pathway associated with salt tolerance. Recognized genes fit diverse groups of salt stress genes viz. abc transporter, betaine, sodium antiporter, sodium symporter, trehalose, ectoine, and choline, that belong to different families of genes involved in the pathway of salt stress. The control sample of the bacterium showed elevated high proportion of transcript contigs (29%) while upto 20% salt stress treated sample of the bacterium showed a higher percentage of transcript contigs (31.28%). A total of 1,288 and 1,133 transcript contigs were measured entirely as novel transcript contigs in both control and treated samples, respectively. The structure and function of 10 significant salt stress tolerant genes of Staphylococcus sp. have been analyzed in this study. The information acquired in the present study possibly used to recognize and clone the salt stress tolerant genes and support in developing the salt stress-tolerant plant varieties to expand the agricultural productivity in the saline system.

Surging demand of fish production for nutritional and livelihood security manifested with irrational use of synthetic growth enhancer and immunostimulants which are fostering the awful health concerned to human being and negatively affecting the beneficial micro-biota in aquatic ecosystem. The need of hour is to use environment friendly herbal therapy, as an alternate to those chemicals and compounds. The Terminalia arjuna is known for its excellent array of ethnomedicinal properties including antimicrobial, antioxidant and was reported to have positive effects on metabolomics of the animals. A 90-day experiment was conducted to ensure effective valorization of Terminalia arjuna bark powder (TABP) based feed in Labeo rohita. Four iso-nitrogenous {305.74 g crude protein (CP)/ kg diet} and iso-caloric {18.15 MJ gross energy (GE)/kg diet} experimental diets were formulated incorporating 0.0, 5.00, 10.00 and 15.0 g TABP /kg feed and designated as TABP0, TABP5, TABP10 and TABP15, respectively. 540 juveniles (average weight, 20.7 g, 45 fish per tank) were randomly stocked in 12 fibre reinforced plastic (FRP) tank (500 L water capacity). Fish were fed twice at 9.30 h and 5.00 h to satiation level. Results of this study revealed the highest growth rates {weight gain percentage (WGP) and specific growth rate (SGR)}, nutrient utilization {protein efficiency ratio (PER), apparent net protein utilization (ANPU), fat retention (FR) and energy retention (ER)} and survival percentage (SRP) in L. rohita at 10 g TABP/ kg feed. While feed conversion ratio (FCR) followed an inverse trend (P 0.05). Viscerosomatic index (VSI) and craniosomatic index (CSI) were significantly affected (P 0.05). Whole body composition was influenced (P 0.05). RNA content and RNA: DNA ratio were positively correlated to growth rates and nutrient retentions (P

The present research study was carried out to investigate the causative agent responsible for infection and mortality of farmed Labeo rohita. Samples of infected fishes were collected from aquaculture farms of West Bengal, India. Biochemical and molecular identification revealed that isolated strain EM4 was Citrobacter freundii. Furthermore, a challenge study was carried out to determine the number of bacterial colonies required for 50% mortality (LD50) of the experimental fish population. LD50 of the pathogenic bacterial isolates (C. freundii) was found to be 1.2 × 103 CFU per fish. Histopathological studies revealed damaged glomerulus in kidney and necrosis of hepatocytes in liver of diseased L. rohita. Additionally, non-specific and specific immune responses of L. rohita were also studied after C. freundii challenge. At early stages of infection, elevated expression level of few non-specific responses viz. respiratory burst activity, myeloperoxidase activity and alpha 2 macroglobulin were observed. However, the antiprotease activity was found to be lowered at the early stages of infections. Sequential changes in the immune-related genes viz. complement component 3 (C3) and interleukin 6 (IL- 6) were also studied in the liver, kidney and muscle tissues of the artificially infected fishes. In the liver and muscle tissues, the C3 gene was significantly up-regulated at the early stages of infections, whereas the IL-6 expression in liver was found to be down-regulated throughout the infection process. Expression of C3 and IL-6 genes in kidney were found to be down-regulated at the early stages of infections, but later, it was up-regulated with the progression of the infection. The result of the present study suggests that C. freundii is a concerning threat towards developing aquaculture sector. The pathology and pathogenesis study will help to understand the infection process as well as in the development of therapies to control the infection.

Vibrio cholerae is a gram-negative bacteria known for causing epidemics and pandemics conditions, comprised of both non-pathogenic and pathogenic strains. The present study identified a non O1, non-O139 V. cholerae (EMM1) serotype isolated from diseased Labeo rohita cultured in a wetland system at Purba Medinipur district, West Bengal, India. Identification of the isolate was done by biochemical test, 16S rRNA gene sequencing and phylogenetic analysis. The in vivo challenge experiment revealed that intraperitoneal injection of EMM1 serotype at a dose of 1.04× 107 CFU/ml resulted in 100% mortality of L. rohita. Furthermore, the presence of hlyA and rtxA virulent genes, confirmed by sequencing, in V. cholerae (EMM1) serotype might be, atleast partially involved in the mortality of L. rohita. In histological analysis, we found that EMM1 serotype challenge had a significant effect in L. rohita like degenerated hepatocytes in the liver, shrunken glomeruli in the kidney, necrosis of the intestinal villi epithelium and degeneration of muscle bundle were observed. Overall, the study demonstrated that, V. cholerae (EMM1) serotype is a potent aquatic microbial pathogen and draws the attention for proper management to prevent the possible occurrence of disease in aquaculture.

Tilapiines are one of the most widely farmed fish species and currently being cultured in > 100 countries in the World. Over the last few years, large-scale mortalities have been reported in tilapia due to infection with orthomyxo-like virus i.e. Tilapia Lake Virus (TiLV) which is considered as a threat to global tilapia industry. In the present study, we report outbreaks of TiLV disease in farmed tilapia in two states, West Bengal and Kerala from India. Diseased fish exhibited lethargy, inappetance and skin erosions with > 85% mortality. TiLV infection was confirmed on the basis of PCR amplification and sequencing of segment 3 of TiLV, histopathology, infection of fish cell line and bioassay. CLUSTALW alignment of the partial sequences of segment 3 of the TiLV revealed that North 24 Parganas (MF502419) and South 24 Parganas (MF582636) of West Bengal, India showed 97.2% and Ernakulam, Kerala, India (MF574205) showed 96.4% similarity with TiLV from Israel (KJ605629.1). In histopathology, typical syncytial giant cells in liver and congestion of the blood vessels along with haemorrhages in sections of brain tissue were observed. The filtered tissue homogenate prepared from liver and brain of affected tilapia produced cytopathic effects in CFF cell line derived from Pristolepis fasciatus. The disease was successfully reproduced in naive tilapia following injection of culture supernatant from infected cell line and TiLV was successfully reisolated from experimentally infected tilapia. This is the first report of TiLV from India and adds to the reports of TiLV outbreaks in five countries across three continents.

The present study was conducted to identify and characterize the etiological agent causing mortality in Indian Major Carp, Rohu ( Labeo rohita ) in West Bengal, India. Diseased fish samples having hemorrhages near the tail and intraperitonial region was collected from culture ponds of Burdwan, West Bengal for the isolation of the pathogenic bacteria. Primarily the bacterium was characterized using biochemical and antibiogram studies. The 16S rRNA gene sequence of the isolated bacteria revealed that the isolate was having 100% homology with Klebsiella pneumoniae (NCBI Accession Number- KY003130). Intraperitoneal injection with 1.05 × 10 6 CFU per fish causes 50% mortality. The challenged fish showed hemorrhages in the intraperitonial region. The histopathology of the challenged fish liver showed vacuolation, necrosis and disruption of hepatocytes. However, focal necrosis and vacuolation was observed in kidney tissue. This study highlights the first time involvement of Klebsiella pneumoniae in the disease outbreak of cultured Labeo rohita . Understanding the pathology and pathogenesis studies of this emerging pathogen in cultured carps would help in control of this disease in aquaculture.

The indiscriminate use of chemicals and antibiotics has prompted the search for an alternative in the form of herbal therapy. An attempt was made to assess the efficacy of serially fractionated solvent extracts of Terminalia arjuna (Roxb) against significant aquaculture microbes. The solvent extracts were designated as Br1-Br7, F1-F7, and L1-L7, and they contained the bark, fruit, and leaves of T. arjuna, as well as 17 bacterial isolates of various types and one fungus, Aphanomyces invadans. The minimum inhibitory concentration (MIC) for bacterial isolates ranged from 0.0 to 25 μg/mL, with an average of 11.39 ± 0.48 μg/mL. The ethanolic bark extract, Br5 (20.83 ± 0.10 mm), and the ethanolic fruit extract, F5 (19.50 ± 0.06 mm) had the greatest inhibition zone against Edwardsiella tarda (B1), and solvent extracts were effective at 0.5 mg/mL and 1 mg/mL for bacterial isolates and fungal strains, respectively. Ellagic acid (m/z 302.01 g/mol), 18-Glycyrrhetinic acid (m/z 470.34 g/mol), Azelaic acid (m/z 188.10 g/mol), and Caffeic acid (m/z 180.04 g/mol) were found to be the most prominent and best fit (> 80 percent) in mzcloud computing. Naringenin (m/z 272.06 g/mol) was discovered in Acetone bark extract, Kanamycin (m/z 426.35 g/mol) and Tetracycline (m/z 444.415 g/mol) in Ethanol bark extract, Orientin (m/z 448.10 g/mol), and Phloretin (m/z 274.08 g/mol) in leaf extracts, and the current study is the first of its kind, and it found that ethanolic bark extract (Br5) has the highest potential antimicrobial activity, followed by methanolic bark extract. As a result, the current study suggests that T. arjuna can be effectively valorized as a broad-spectrum antimicrobial for disease management and human welfare.

Effective monitoring of Salmonella contamination in seafood processing to conform the requirements of HACCP is a great challenge today. Such challenges can be effectively addressed, if the conventional detection methods are replaced with DNA-based molecular methods. Accordingly, it was aimed to develop a robust PCR protocol for specific detection of Salmonella spp. Out of the different primers screened, one pair of primers developed in this study targeting invA gene demonstrated 100% inclusivity for a wide range of Salmonella serotypes and 100% exclusivity for wide range of non-target species. The in silico analysis of the nucleotide sequence obtained from the PCR product suggests its potential as a hybridization probe for genus specific detection of Salmonella spp. contamination. The PCR protocol was sensitive enough to detect 15 cells per reaction using crude DNA prepared within a short time directly from artificially contaminated shrimp tissue. The study demonstrated that the result of PCR reaction can come out on the same day of sample arrival. Incorporation of this pair of primers in a multiplex PCR designed for simultaneous detection of four common seafood-borne human pathogens yielded 147 bp, 302 bp, 403 bp, and 450 bp distinct DNA bands specifically targeting E. coli, toxigenic Vibrio cholerae, Salmonella spp., and V. parahaemolyticus, respectively in a single PCR tube. The PCR methods developed in this study has the potential to be used in the seafood processing plants for effective monitoring of CCPs required for implementation of HACCP-based quality assurance system.

Beneficial microbes are all around us and it remains to be seen, whether all diseases and disorders can be prevented or treated with beneficial microbes. In this study, the presence of various beneficial bacteria were identified from the sediments of Indian major Rivers Ganga and Yamuna from nine different sites using a metagenomic approach. The metagenome sequence analysis using the Kaiju Web server revealed the presence of 69 beneficial bacteria. Phylogenetic analysis among these bacterial species revealed that they were highly diverse. Relative abundance analysis of these bacterial species is highly correlated with different pollution levels among the sampling sites. The PCA analysis revealed that Lactobacillus spp. group of beneficial bacteria are more associated with sediment sampling sites, KAN-2 and ND-3; whereas Bacillus spp. are more associated with sites, FAR-2 and ND-2. This is the first report revealing the richness of beneficial bacteria in the Indian rivers, Ganga and Yamuna. The study might be useful in isolating different important beneficial microorganisms from these river sediments, for possible industrial applications.

Aquaporins (AQPs) are a family of membranebound proteins that facilitate the hydration of cells. The identification of the AQP1a gene in common carp (Cyprinus carpio) from mRNA transcript and its expression analysis during reproduction was performed to study its role in gonad cell hydration. The AQP1a gene transcript was partially amplified using gene-specific primers and the amino acid sequence was predicted. Based on the partial transcript sequence, a phylogenetic tree was prepared using the MEGA4 software which suggested that the AQP1a gene of common carp is closely related to that of Danio rerio. Differential tissue expression was analysed using real-time PCR which indicated that the expression of AQP1a was significantly higher in the eye, kidney, and liver with 32.98±1.33 folds higher in the eye when compared to the testis. In both the male and female gonads, the highest expressions were observed after 6h of synthetic hormone injection in comparison to gonads belonging to the individual without any injection. However, the gene expression declines gradually in 12h and 24h post-injection. Expression analysis of gonad during different phases of reproduction suggests that there is a significant increment of AQP1a expression from the resting phase to the pre-spawning phase and from pre-spawning to spawning phase in the case of male gonad. However, there was no significant difference in expression during the resting and pre-spawning phase in the female gonad, although expression was significantly higher during the spawning phase. Key words Aquaporin; Gonad; Reproduction: Common carp; gene expression

The innate immune system offers the first line of defense against invading microbial pathogens through the recognition of conserved pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors (PRRs). The host innate immune system through PRRs, the sensors for PAMPs, induces the production of cytokines. Among different families of PRRs, the retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs), and its mitochondrial adaptor ie, the mitochondrial antiviral-signaling (MAVS) protein, are crucial for RLR-triggered interferon (IFN) antiviral immunity. Recent studies have shown that the N-terminal caspase recruitment domain (CARD) and transmembrane domain play a pivotal role in oligomerization of black carp MAVS (BcMAVS), crucial for the host innate immune response against viral invasion. In this study, we have used molecular modeling, docking, and molecular dynamics (MD) simulation approaches to shed molecular insights into the oligomerization mechanism of BcMAVSCARD . MD simulation and interaction analysis portrayed that the type-I surface patches of BcMAVS CARD make the major contribution to the interaction. Moreover, the evidence from surface patches and critical residues involved in the said interaction is found to be similar to that of the human counterpart and requires further investigation for legitimacy. Altogether, our study provided crucial information on oligomerization of BcMAVS CARDs and might be helpful for clarifying the innate immune response against pathogens and downstream signaling in fishes.

The acute phase proteins are biochemically and functionally unrelated protein predominantly synthesized in the liver. The local inflammatory cells i.e. macrophages and neutrophils secretes various cytokines like IL-1, IL-6, IL-8 (interleukins) and TNF-α into bloodstream in response to injury and tissue damage, which stimulate hepatocytes to produce protein and release them into the circulation; these proteins are called as acute phase protein (e.g. C-reactive protein (CRP), serum amyloid A (SAA), metal binding protein, lysozyme, lectin, etc.). The acute phase proteins are involved in variety of defence related activities e.g., inactivation of proteolytic enzymes, preventing the distribution of infectious agents (i.e. either by destruction of microorganism or making microbial cell suitable for cell response by modifying surface targets) and restoration of damage tissue and healthy condition. A number of well-known acute phase proteins have disease prognosis importance and change in the APPs level reflects the presence and intensity of inflammation during infection or injury. Further studies are still necessary to develop our knowledge in diagnostic importance of different acute phase proteins in fish and more efforts are needed to differentiate the APPs levels in case of viral, bacterial and parasitic diseases.

The major hindrance in the development and sustainability of aquaculture industry is the occurrence of various diseases in the farming systems. Today, preventive and management measures are central concern to overcome such outbreak of diseases. Immunostimulants are considered as an effective tool for enhancing immune status of cultured organisms. Among different immunostimulants used in aquaculture practices, β-glucan is one of the promising immunostimulant, which is a homopolysaccharide of glucose molecule linked by the glycoside bond. It forms the major constituents of cell wall of some plants, fungi, bacteria, mushroom, yeast, and seaweeds. Major attention on β-glucan was captivated with the gain in knowledge on its receptors and the mechanism of action. The receptor present inside the animal body recognizes and binds to β-glucan, which in turn renders the animal with high resistance and enhanced immune response. This review highlights β-glucan as an immunostimulant, its effective dosages, and route of administration and furthermore provides an outline on role of β-glucan in enhancing growth, survival, and protection against infectious pathogens pertaining to fishes and shellfishes. Study also summarizes the effect of β-glucan on its receptors, recognition of proteins, immune-related enzymes, immune-related gene expression and their mechanisms of action.

The effect of different concentrations of synthetic androgen 17?- methyl-testosterone (MT) on the adult fish,Colisa lalia was studied in the present investigation. It was found that fishes fed with homogenous mixture ofthe hormone in ethyl alcohol, exhibited phenotypically, morphometric, gonadal changes and differences in GSIvalue. Significant differences for length, weight, body color and GSI values were observed between hormonestreated and control groups. Fishes fed with hormonal doses of 10 and 15 mg/Kg feed showed significantlyelevated body color compared to 5 mg/Kg feed. Length, weight and GSI values were found significantly higherin 10 mg than 5mg/Kg and control group. The highest mean length and mean weight of fish was recorded as4.76±0.13 mm and 1.50±0.15g respectively with the hormone treatment of 10mg/Kg of feed. The present studyrevealed that the synthetic hormone had no significant effect on the gonad development of C. lalia.

An experiment was conducted to breed a near threatened Cyprinid Osteobrama belangeri in captivity through hormonal inducement. Carp pituitary extract (CPE) and three different GnRH based synthetic hormones viz., Ovaprim, Ovatide and Wova-FH were used as inducing agents. Experiment was conducted following a Completely Randomized Design (CRD). The brooders were injected with different doses of hormones and kept in the breeding hapas at 2:1 male to female ratio. All the inducing agents induced the fishes to breed, whereas no breeding was observed in the control set. Spawning success rate varied depending on the rate of inducement and the type of inducing agent used. CPE at a dose of 9 mg kg−1 of female and 3 mg kg−1 of male as well as the synthetic hormones at 0.5 ml kg−1 of female and 0.2 ml kg−1 of male brooders were found to be effective in inducing the fishes to breed in captivity. Efficacy of the synthetic hormones was significantly higher than that of CPE (P