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The population structure of Barbodes carnaticus species was studied using conventional (based on body morphometrics and meristic) and image-based analysis (truss network system) methods. The study was carried out with four stocks, namely Karnataka (KA) and Tamil Nadu (TN) stocks from the River Cauvery, Kerala (KE) stock from the River Chalakudy and farm-reared stock (CI) from Central Institute of Freshwater Aquaculture, Bangalore. A total of 27 morphometric, 9 meristic and 30 truss measurements were used in the study for the stock structure. Fifteen landmarks were used to generate 30 truss distance measurements. The principal component analysis (PCA), factor analysis (FA), discriminant function analysis (DFA) and cluster analysis (CA) were deployed to determine the variation using both the conventional and truss variables. Variations (86.9%) among the morphometric characters were explained by five principal components, while four principal components explain 96.01% of the variation among the truss distances. DFA using conventional method correctly classified 100% of the original grouped classes of the KA, KE and CI and 93.8% of TN stocks. The DFA employed with truss distance was classified into the stocks CI, KA, KE and TN, and the values are 100, 89.1, 8.6 and 6.1%, respectively. Factor analysis based on truss morphometry showed that factor one is related to body shape and factor two is related to head shape. Two clusters were identified in both the conventional and the truss distance analysis. Truss distance-based cluster showed that the KE and CI stocks are similar compared to the TN stock. In contrary, morphometry-based cluster showed the KE and TN stocks are similar compared to CI stock. The multivariate analysis showed that the farm-reared stock (CI) is different from the wild stocks (KA, KE and TN). This study explained that the combination of the conventional and image-based truss network analysis helps to discriminate various stocks of B. carnaticus. Based on the PCA, bilinear data models were generated using R 3.5.3 software for predicting the stock of each individual. Stock discrimination of this species was mainly due to the geographic isolation, river ecology and temperature variations. The stocks of B. carnaticus are highly exploited from the studied rivers, and the species is an important candidate for species diversification to enhance aquaculture production. Within stock variations are found to be minimum in the present morphometric study, hence the gene pool identification and marker study are required for better understanding of the stocks. This stock structure study may help to develop conservation programmes for this endemic species through a more scientific approach.

Studies on Sisorinae systematics have been largely restricted to morphological data with few studies on examination of phylogenetic relations. However, no study has been done to evaluate genetic distance of the genera under Sisorinae sub-family and detailed phylogenetic relations within it. We used nuclear recombination activating 2 (rag2) gene and mitochondrial cytochrome c oxidase I (COI) gene from 64 species to examine genetic differentiation and phylogenetic relationships within 11 Asian Sisorinae genera. The range of interspecies K2P distance for rag2 was 0-0.061 and COI was 0-0.204. Phylogenetic analysis based on maximum likelihood (ML) and Bayesian (BI) approaches for each locus individually and for the concatenated rag2 and COI sequences revealed three major subclades viz. Bagariini, Sisorini and Erethistini under subfamily Sisorinae. The analysis based on COI gene showed ((Sisorini, Bagariini), Erethistini) relationship. Rag2 and combined rag2 and COI showed ((Sisorini, Erethistini), Bagariini) relationship. Combined rag2 and COI analyses resulted into better resolved trees with a good bootstrap support. In this study, new record of Pseudolaguvia foveolata (Erethistini) has been documented based on 13 specimens collected from Torsa River, Jaldapara, Alipurduar district, West Bengal, India (26°43'44.66″ N and 89°19'32.34″ E), extending its distribution range in Brahmaputra drainage, India. The genetic distance between the P. foveolata new record and the reported P. foveolata (holotype: UMMZ 244867) was 0.00 at both rag2 and COI locus and it was further grouped with P. foveolata Type specimen (holotype: UMMZ 244867) with 100% bootstrap support. This report gives additional information on occurrence of the species P. foveolata, along with discussion on morphometric, meristic and molecular (COI and rag2 gene) data.

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.

Vibrio parahaemolyticus is known to cause disease and infection in humans. This study was conducted to understand the prevalence of V. parahaemolyticus and the presence of virulence factors in environmental isolates of V. parahaemolyticus, collected from three major shrimp producing states viz, West Bengal, Andhra Pradesh and Gujarat of India during February 2014 to June 2017. Total 183 V. parahaemolyticus were isolated from moribund shrimp and identified using toxR and 16S rRNA gene. Polymerase Chain Reaction (PCR) was performed to detect virulence genes under T3SS1 and T3SS2 along with AHPND. All the isolates showed presence of vcrD1, vp1680 and vopD1 gene under T3SS1 but negative for AHPND. Only 3% of isolates showed presence of all the virulence genes (vcrD2, vopD2, vopB2 and vopC) used in the present study under T3SS2. The isolates were also tested for the presence of tdh, trh or both the genes; 8% of the isolates had trh gene and 3% of the isolates had tdh gene. The genetic diversity within and between V. parahaemolyticus isolated from three different geographical locations, was analyzed by using 16S rRNA gene. Though the biotype diversity (h) was high for all three populations, phylogenetic study of V. phaemolyticus revealed an admixture of biotypes. Tajima's D (−2.59470; p

Enterocytozoon hepatopenaei (EHP) is an emerging microsporidian pathogen in shrimp aquaculture. In the present study, prevalence rate of EHP in cultured Litopenaeus vennamei from West Bengal, east coast of India, was investigated. Histology of hepatopancreas of the infected animals showed eosinophilic to basophilic inclusions in the epithelial cells with moderate necrotic tubular detachment from the basal membrane. Extracted DNA from the hepatopancreatic tissues were subjected to PCR by using two different sets of primers targeting the ssu rRNA genes. An expected PCR product of 951 and 510 bp were yielded for the EHP-positive shrimp samples. Based on the BLASTP, the sequence of ssu rRNA gene (KU179095) of the collected samples showed 100% homology with EHP ssu rRNA gene sequences submitted in NCBI from different countries viz. Vietnam, Thailand, China and India. Further, all the field samples were found to be EHP+ by using a new second-generation primer targeting the spore wall protein gene (SWP) of EHP. For detection of EHP, 119 samples from East Midnapur district, 50 samples from North 24 Parganas district and 50 Samples from South 24 Parganas district were being screened. Overall prevalence rate of EHP in the cultured L. vennamei farm in West Bengal was estimated to be 84.9%, which was highest in comparison to earlier reports in India. Our finding showed that EHP could be detected from slow growing shrimps as well as in some cases from White Faeces Syndrome-affected animals. This is the first report on the occurrence of Enterocytozoon hepatopenaei in cultured L. vannamei in West Bengal, east coast of India.

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.

Vibrio parahaemolyticus is a gram-negative halophilic bacterium responsible for gastrointestinal infection in human and vibriosis in aquatic animals. The thermostable direct hemolysin (tdh), tdh-related hemolysin (trh) and thermolabile hemolysin (tlh) positive strains of V. parahaemolyticus were identified from brackishwater aquaculture farms of West Bengal and Andhra Pradesh, India. Moreover, the presence of other virulent genes like vcrD1, vopD, vp1680 under type three secretion system 1 (T3SS1) and vcrD2 vopD2, vopB2, vopC2 under type three secretion system 2 (T3SS2) were detected in tdh positive strain of V. parahaemolyticus. Furthermore, the study revealed that the tdh and trh positive isolates were resistant to β-lactam antibiotics and were able to lyse more than 95% of human Red Blood Cells (RBCs). In addition, both the isolates showed high cytotoxicity in Human Embryonic Kidney (HEK) cell line compared to tlh positive strain. Additionally, intraperitoneal and oral administration of tdh and trh positive strain of V. parahaemolyticus in Indian Major Carp, Labeo rohita caused 100% mortality at the level of 2.0 × 108 CFU ml−1 and 1.6 × 108 CFU ml−1, respectively. In contrast, only 10% mortality was observed in the case of tlh positive strain at the level of 2.5× 108 CFU ml−1. The histopathological changes like infiltration of blood cells and degenerated hepatic tissue in the liver of L. rohita were observed after the experimental challenge. The changes like degeneration of glomeruli, necrosis of renal tubules and Bowman's capsule were observed in the kidney section. Ragged, irregular shaped villi and necrosis of the villus were observed in the intestinal lumen. Overall, the study demonstrates that isolated V. parahaemolyticus is a potent aquatic microbial pathogen. Additionally, as V. parahaemolyticus is also a human pathogen and might pose a threat to the human population, proper management strategies are required to prevent the possible occurrence of disease.

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 this study, we report the presence of a microbial community of bioremediation potential in terms of relative abundance and taxonomic biodiversity in sediment samples of river Ganga and Yamuna, India at nine different sites. Metagenomic libraries were constructed using TruSeq Nano DNA Library Prep Kit and sequenced on NextSeq 500 by Illumina Next Generation Sequencing (NGS) technology. Bioremediation bacteria belong to 45 genera with 92 species and fungi belong to 13 genera with 24 species have been classified using Kaiju taxonomical classification. The study revealed that Proteobacteria was the most dominant bacterial flora, followed by Actinobacteria, Firmicutes, and Deinococcus–Thermus. PCA analysis revealed that bioremediation bacteria viz. Streptomyces bikiniensis, Rhodococcus qingshengii, Bacillus aerophilus, Pseudomonas veronii, etc., were more dominant in highly polluted river stretch as compared to less polluted river stretch. Similarly, the relative abundance of bioremediation fungi viz. Phanerochaete chrysosporium and Rhizopus oryzae, etc., were significantly correlated with the polluted Kanpur stretch of river Ganga. Several protein domains, which play a pivotal role in bioremediation in the polluted environments, including urea ABC transporter, UrtA, UrtD, UrtE, zinc/cadmium/mercury/lead-transporting ATPase, etc., were identified using protein domain analysis. The protein domains involved in pesticide biodegradation viz. P450, short-chain dehydrogenases/reductases (SDR), etc., were also discovered in river sediment metagenomics data. This is the first report on the richness of bioremediation microbial communities in the Ganga and Yamuna riverine ecosystems, highlighting their importance in aquatic pollution management.

The feasibility of near- infrared (NIR) spectroscopy to discriminate the freshness of an Indian Major Carp, Rohu (Labeo rohita) was investigated in this paper. The spectroscopic readings of Rohu samples were recorded for the wavelength range between 900 and 1700 nm in absorbance mode. The Principal Component Analysis (PCA) was applied to analyze the spectral data and distinguishable clusters were obtained. Study revealed that, the freshness of the Rohu could be distinguished by NIR Spectroscopy. The Separability Index (SI) of the raw data was also measured as 873.7008. Preliminary results showed that, this technique could be applied for discrimination of Rohu fish freshness.

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.

Plesiomonas shigelloides was isolated from diseased silver carp in Kolkata Wetland, West Bengal, India. It was associated with mortality of Silver Carp, Hypophthalmichthys molitrix, which is the most widely cultivable fish species in fresh water aquaculture. The P. shigelloides was identified based on the biochemical and molecular characterization and the pathogenicity was studied on H. molitrix. The 16S rRNA gene sequence of the present isolate (NCBI GenBank Accession Number- KX986915) revealed that, the isolate was 100% identical with P. shigelloides (NCBI GenBank Accession Number- MF100995). P. shigelloides killed 10–100% fish in experimental infection and the LD50 value was calculated as 1.3× 105CFU per fish with intraperitoneal injection. The challenged fish had subcutaneous haemorrhagic ulcers and reddening at injection sites, however there was no clinical sign observed in the gill. The histology of experimentally challenged H. molitrix showed the kidney alterations and exhibited shrinkage of epithelial cells in renal tubule and enlargement of glomerular cells.Liver showed focal accumulation of edematous fluid, necrosis and infiltration of heterophils indicative of bacterial infection. The pathology and pathogenesis studies of this pathogen in inland open waters like wetlands and lakes would help in management of the outbreak of disease in these aquatic ecosystems.

Aquaporins (AQPs) constitute a super family of major intrinsic proteins (MIPs) and aquaporin 4 (AQP4) is one of the most popular protein, participating in different types of bio-physiological pathways in animal, plant and even in bacteria. Zebrafish, considered as a novel model organism, possess an Aquaporine 4 protein (zAQP4) that shares a high degree of homology with mammalian orthologs which was mostly found to be express in brain, ovary, testis, and low levels in other tissues. To focus more light on AQP4 medical related therapeutic applications, the structure of zAQP4 as a drug target protein is extremely essential and there is no such structural information available in protein data bank (PDB). Herein, for the first time we generate the 3D structure of zAQP4 was modeled through a Homology modeling approach. The root-mean-square deviation (RMSD) of atomic positions between the generated model structure and human AQP4, revealed 69.2% sequence identity over align region with RMSD value 2.723 A. Structural integrity of the model was assessed using molecular dynamics simulation studies to achieve a better understanding of the progress, structure, and function of AQP4. Finally residual involvements for druggable pocket identification were made and some important residues such as VAL-237, PRO-272, GLN-274, PRO-277, TYR-278, VAL-118, LEU-122 and LEU-126 which shows highest druggability probability (1.0) that can emphasize the importance of aquaporin-4 as a target protein in the field of drug research in near feature.

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.

Octopuses are marine benthic stenohaline organisms that exhibit a short range of migration within marine habitats and avoid brackish or freshwater environments. The present document is the first record of 'pouched octopus', Cistopus platinoidus Sreeja et al. 2015, from a tropical estuarine system. We collected 15 specimens of C. platinoidus from the set bag nets operated in Narmada estuary, located 40 km away from the river mouth with an in-situ salinity of 17.63. This report is a new finding of an octopus species from a brackish water ecosystem outside its normal inhabitance range to the best of our knowledge.

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.

The present study explains the population structure and genetic diversity of medium carp Labeo gonius by analyzing partial sequence of mitochondrial DNA cytochrome b gene. Labeo gonius is a lower risk Near Threatened species, distributed throughout the North Indian major rivers, reservoirs and lakes. This species has a larger scope as an alternative candidate species in carp aquaculture system. In the present investigation, 223 individuals of Labeo gonius were collected from five locations of phylo-geographically isolated riverine ecosystems of India resulted in 12 haplotypes. These haplotypes showed 14 variables, out of which 9 were singletons and 5 were parsimony informative sites of nucleotide positions. The haplotypes H1 was considered as ancestral haplotype. All the haplotypes were connected to each other by 1-4 nucleotide mutations. The Narmada haplotypes (H10; H11 and H12) were isolated from H1 by four nucleotide mutations. The analyses resulted maximum expansion events (τ = 4.13672) in Narmada, with Fst scores more than other population pairs. The analysis of molecular variance (AMOVA) showed significant genetic differentiation among populations (ØST = 0.69470, p .000). The genetic differentiation patterns were significantly consistence with geographical distributions. This study rejected the null hypothesis of single panmictic population of medium carp, Labeo gonius in Indian water.

Indian Major Carp Labeo rohita (Ham.) is the most preferred cultivable fish species under freshwater aquaculture in India. The present study was conducted to characterize the bacteria at molecular level and to understand its pathogenicity associated with mortality of farmed rohu, Labeo rohita . Diseased fish samples were collected from cultured ponds of Nadia, West Bengal, India for the isolation of the pathogen. The 16S rRNA gene sequence of the bacteria revealed that the isolate was 100% identical with Acinetobacter baumannii (NCBI Accession Number KT156752). Intraperitoneal injection with the isolate at the level of 2.1 × 10 8 cells/ml in fish causes mortality. The challenged fish had loss of mucus and reddish lesion near the pectoral fin, however there was no sign in the gill. The histology of experimentally challenged Labeo rohita showed hemorrhages and shrunken glomeruli with densely basophilic nuclei in kidney whereas degenerated hepatic tissue and increased hepatocyte vacuolation in liver. This study underlines the first time involvement of Acinetobacter baumannii in the disease outbreak of Labeo rohita . The pathology and pathogenesis studies of this emerging pathogen in cultured carps would help in management of the outbreak of disease in aquaculture.

Catla (Catla catla) is a one of the most harvested Indian major carps and is widely cultured fish species in Indian subcontinent. In the present study, genetic variability between hatchery and wild stocks of Catla was surveyed using sequence data of mitochondrial DNA of partial 307 bp of cytochrome b region. A total of 174 Catla individuals were examined from three different river basins and hatcheries. Significant genetic heterogeneity was observed for the sequence data (F

Length-weight relationship (LWR) of five species of the genus Labeo (Family: Cyprinidae) namely L. rohita (Hamilton,1822), L. calbasu (Hamilton,1822), L. bata (Hamilton,1822), L. dyocheilus (McClelland, 1839) and L. porcellus (Heckel, 1844), based on 214 specimens collected from Cauvery River in Peninsular India, were established. Sampling was carried out from December 2017 to December 2018 at around three months interval. The value of regression coefficient (b) ranged from 2.6147 ( L. bata ) to 3.2855 ( L. dyocheilus ). A new maximum length of 41 cm for L. porcellus has been recorded. For L. porcellus, LWR is established for the first time while for other species (except L. rohita ); it is estimated for the first time from a peninsular river in India. Relative condition factor estimated for the five fish species did not show large scale variation (1.001 to 1.019). Keywords: Cauvery, Condition factor, Labeo , Length-weight relationship

Peptidoglycan recognition proteins (PGRPs) are the important members of pattern recognition receptors (PRRs) family and represents major constituent of innate immunity. Although PGRPs are structurally conserved through evolution; their involvement in innate immunity are different in vertebrates and invertebrates. They are highly specific for the recognition and in some cases, hydrolyze bacterial peptidoglycans (PGNs). Zebrafish PGRPs (zPGRPs) have both peptidoglycans lytic amidase activity and broad-spectrum bactericidal activity, but far less is known about how these receptors recognize these microbial ligands. Such studies are hindered due to lack of structural and functional configuration of zPGRP. Therefore to fill the research gap, we inferred the three-dimensional architecture of the zPGRP2 through theoretical modeling and investigated the conformational and dynamic properties through molecular dynamics simulations. Docking information of microbial ligands i.e., muramyl pentapeptide-DAP (MPP-Dap), muramyl pentapeptide-LYS (MPP-Lys), muramyl tripeptide-DAP (MTP-Dap), muramyl tripeptide-Lys (MTP-Lys), muramyl tetrapeptide-DAP (MTr-Dap), muramyl tetrapeptide-LYS (MTr-Lys) and tracheal cytotoxin (TCT) in Autodock Vina revealed β1, α2, α4, β4, and loops connecting β1 - α2, α2 - β2, β3 - β4, and α4 - α5 as the key interacting domains participate in ligand recognition. Several conserved amino acids i.e., His31, His32, Ala34, Ile35, Pro36, Lys38, Asp60, Trp61, Trp63, Ala89, His90, Asp106, His143, and Arg144 are predicted to essential for binding and provides stability to these zPGRP-PGN complexes. Our study provides basic molecular information for further research on the immune mechanisms of PGRP's in Zebrafish. The plasticity of the zPGRP's binding site revealed by these microbial ligands suggests an intrinsic capacity of the innate immune system to rapidly evolve specificities to meet new microbial challenges in the future.

The Hilsa shad, Tenualosa ilisha popularly known as ‘Hilsa’, is one of the most commercially important fish species in South Asian countries. The species is widely distributed from the Persian Gulf to Bay of Bengal and ascends into estuaries, rivers and brackish-water lagoons of the Indo-Pacific region. Recently, the availability of hilsa has drastically dwindled in aquatic systems across this region, due to anthropogenic pressures, mainly intensive fishing and river obstruction by dams and barrages. Climate change may also be contributing to the declining populations. Hence, there is an urgent need for conservation of the species. In addition, hilsa is of great cultural and economic importance among the peoples of Ganga-Brahmaputra-Meghna basin, with very high market demand and increasingly high prices, presently an average of around US$ 12 per kg for consumers both in India and Bangladesh. Many attempts at hilsa breeding and culture have been made across South Asia, particularly in India and Bangladesh, since the 1900s. To date, no breakthrough has been achieved in completing the life cycle in captivity. This review provides an insight into the status of artificial breeding, larval rearing and culture of this species, and identifies research gaps that need to be addressed by future aquaculture development programmes for hilsa in South Asia.

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

In mammalian systems, the conserved cyclin-dependent protein kinases (CDKs) control the process of cell division and curb the transcription mechanism in response to diverse signaling events that are essential for the catalytic activity. In zebrafish, zCDKL5 portrays differential expression profiling in several tissues and presumed to play a vital role in the neuronal development. In this present study, the sequence-structure relationship and mode of ATP binding in zCDKL5 was unveiled through theoretical modeling, molecular docking, and MD simulations. Like human CDKs, the modeled zCDKL5 was found to be bipartite in nature, where, ATP binds to the central cavity of the catalytic domain through a strong network of H-bonding, electrostatic, and hydrophobic interactions. MD simulation portrayed that conserved residues, viz, Ile10, Gly11, Glu12, Val18, Val64, Glu81, Cys143, and Asp144 were indispensable for tight anchoring of ATP and contribute to the stability of the zCDKL5-ATP complex. MM/PBSA binding free energy analysis displayed that van der Waal energy (ΔG vwd ) and Electrostatic energy (ΔG ele ) were the major contributors towards the overall binding free energy. Thus, the comparative structural bioinformatics approach has shed new insights into the dynamics and ATP binding mechanism of zCDKL5. The results from the study will help to undertake further research on the role of phosphorylated CDKL5 in the onset of neurodevelopmental disorders caused by mutations in higher eukaryotic systems.

Intensive fish farming systems have led to increase in disease incidence, due to higher stocking density, high organic matter levels, and poor quality of the aquatic environment. Diseased fish samples showing hemorrhages and reddish lesions were collected from different freshwater fish farms located at three different districts of West Bengal, India (Burdwan, North 24 Parganas, and Nadia). The present study was conducted to evaluate the genetic diversity of ten different Klebsiella pneumoniae strains isolated from different infected freshwater fish samples based on 16S rRNA gene sequence analysis. Primarily, Klebsiella-specific media was used for the isolation and characterization of Klebsiella pneumoniae. Further, through a biochemical test, all the strains were confirmed as K. pneumoniae. PCR analysis of 16S-23S internal transcribed spacer (PCR ribotyping) was carried out to study the species variation within different Klebsiella pneumoniae isolates. For all the isolates, a conserved PCR ribotype pattern was observed while differing from other bacterial species. Phylogenetic study showed the high degree of homology with diverse source of other strains. The multiple antibiotic resistance (MAR) values of the present study for the isolates were found to be 0.468. MAR value above 0.2 indicates that the source of isolation was highly contaminated with antibiotics. Based on the 16S rRNA gene sequence analysis, the present study revealed the genetic diversity of Klebsiella pneumoniae isolated from the different diseased fish farms of West Bengal. All the strains were found to be hypermucoviscous and multidrug-resistant, thus making it pathogenic towards the host organisms. Further, the study revealed a high prevalence of K. pneumoniae in aquaculture farms, representing a risk towards successful aquaculture.

Vibrio parahaemolyticus is a major seafood-borne pathogen that causes life-threatening gastroenteric diseases in humans through the consumption of contaminated seafoods. V. parahaemolyticus produces different kinds of toxins, including thermostable direct hemolysin (TDH), TDH-related hemolysin (TRH), and some effector proteins belonging to the Type 3 Secretion System, out of which TDH and TRH are considered to be the major factors for virulence. Although TRH is one of the major virulent proteins, there is a dearth of understanding about the structural and functional properties of this protein. This study therefore aimed to amplify the full length trh gene from V. parahaemolyticus and perform sequence-based analyses, followed by structural and functional analyses of the TRH protein using different bioinformatics tools. The TRH protein shares significant conservedness with the TDH protein. A multiple sequence alignment of TRH proteins from Vibrio and non-Vibrio species revealed that the TRH protein is highly conserved throughout evolution. The three dimensional (3D) structure of the TRH protein was constructed by comparative modelling and the quality of the predicted model was verified. Molecular dynamics simulations were performed to understand the dynamics, residual fluctuations, and the compactness of the protein. The structure of TRH was found to contain 19 pockets, of which one (pocket ID: 2) was predicted to be important from the view of drug design. Eleven residues (E138, Y140, C151, F158, C161, K162, S163, and Q164), which are reported to actively participate in the formation of the tetrameric structure, were present in this pocket. This study extends our understanding of the structural and functional dynamics of the TRH protein and as well as provides new insights for the treatment and prevention of V. parahaemolyticus infections.

The complete mitogenome of Osteobrama belangeri is described using Ion Torrent (PGM sequencer), which was 16,609 bp in size comprising 13 mRNAs, teo rRNA genes, 22 tRNAs, and 926 bp as D-Loop contr...

A total of 206 bacterial isolates were obtained from soil, water and sediment samples using three different culture media with a pH of 7.3 ± 0.2 and an incubation temperature of 37 °C. Of these isolates, 48 bacteria were selected for functional screening and molecular characterization. The functional screening for salt stress tolerance revealed that, 17 bacteria were identified as moderately halotolerant and 31 were halophilic, capable of growing at 5–15 % (w/v) and ≥15 % (w/v) of NaCl concentration respectively. The 16S rRNA gene sequence analysis and taxonomic identification of isolates were performed using Ribosomal Database Project Release-10 and SILVA SSU database. Based on the sequence length >1,300 bp, 40 bacteria were identified out of 48 isolates. Study showed that, Staphylococcus spp. was highly resistant to salt stress followed by Enterococcus faecalis, Vagococcus fluvialis and Vibrio parahaemolyticus. The phylogenetic analysis revealed that, 24 bacterial isolates belong to Firmicutes and 16 isolates come under Proteobacteria. These bacterial strains would be of great use for prospecting novel and candidate salt stress tolerant genes.

Nucleotide binding and oligomerization domain (NOD2) is a key component of innate immunity that is highly specific for muramyl dipeptide (MDP)—a peptidoglycan component of bacterial cell wall. MDP recognition by NOD2–leucine rich repeat (LRR) domain activates NF-κB signaling through a protein–protein interaction between caspase activating and recruitment domains (CARDs) of NOD2 and downstream receptor interacting and activating protein kinase 2 (RIP2). Due to the lack of crystal/NMR structures, MDP recognition and CARD–CARD interaction are poorly understood. Herein, we have predicted the probable MDP and CARD–CARD binding surfaces in zebrafish NOD2 (zNOD2) using various in silico methodologies. The results show that the conserved residues Phe819, Phe871, Trp875, Trp929, Trp899, and Arg845 located at the concave face of zNOD2–LRR confer MDP recognition by hydrophobic and hydrogen bond (H-bond) interactions. Molecular dynamics simulations reveal a stable association between the electropositive surface on zNOD2–CARDa and the electronegative surface on zRIP2–CARD reinforced mostly by H-bonds and electrostatic interactions. Importantly, a 3.5 A salt bridge is observed between Arg60 of zNOD2–CARDa and Asp494 of zRIP2–CARD. Arg11 and Lys53 of zNOD2–CARDa and Ser498 and Glu508 of zRIP2–CARD are critical residues for CARD–CARD interaction and NOD2 signaling. The 2.7 A H-bond between Lys104 of the linker and Glu508 of zRIP2–CARD suggests a possible role of the linker for shaping CARD–CARD interaction. These findings are consistent with existing mutagenesis data. We provide first insight into MDP recognition and CARD–CARD interaction in the zebrafish that will be useful to understand the molecular basis of NOD signaling in a broader perspective. Copyright © 2014 John Wiley & Sons, Ltd.

Soil salinization has become a severe constraint for crop production world-wide which necessitated development or induced enhancement of salt stress tolerance in plant life to sustain production in saline lands. Recognition and prospecting of valuable stress tolerant genes from natural microbial resources of saline habitat is obscure to date. Therefore, the investigation was towards isolation and characterization of marine salt stress tolerant microbes along the East coast of India for revelation of effective salt stress tolerant genes. Salt stress tolerance was assessed from 98 bacterial isolates obtained from 28 water and soil samples. Among them, 35 isolates which failed to grow beyond 4% salt were discarded and remainder 63 isolates were selected for further functional analysis and only seven isolates recorded ≥8% NaCl stress tolerance. Phylogeny revealed that four isolates belong to Firmicutes and three isolates were members of Proteobacteria. Ribosomal Database Project Release-11 and SILVA SSU database based genotyping and taxonomic identity analysis confirmed that the higher (20%) salt stress tolerant bacteria were Staphylococcus sp., Enterococcus sp., Enterobacter sp. and Proteus sp. To investigate candidate, as well as, novel salt stress tolerant genes, the seven bacterial isolates would provide new horizon to focus on the recent developments of salinity stress tolerance. In addition, the findings evidently point out the diversity of salt stress tolerant marine bacteria in coastal Odisha and West Bengal, India.

The genetic diversity of five feral populations of Asian Sea bass, Lates calcarifer collected from five isolated locations in India viz., Paradeep, Chilka lake, Kakinada, Chennai and Mumbai was studied using randomly amplified polymorphic DNA. Out of 20 primers screened, 5 decamer random primers amplified a total of 373 DNA bands of which 137 bands were polymorphic. The Kakinada population showed the highest polymorphism (65.71 %) whereas the Chennai population showed the lowest (48.28 %). The inter-population genetic similarity (GS) values estimated for the five populations were checked by one-way ANOVA and found to be significantly different at P

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.

Polyunsaturated fatty acids (PUFAs) consumption is known to be associated with a number of health benefits and fish oils, especially marine, are rich in PUFAs. Tenualosa ilisha, a highly preferred food fish in South-Asian countries, is rich in oils; however, information on fatty acid profiles of different size-groups of hilsa is scanty. In the present investigation, information on fatty acid profiles of different size groups of hilsa has been generated. Analysis showed that medium-sized fish contained the highest amount of unsaturated fatty acids as well as ω-3 PUFAs, EPA plus DHA and the lowest amount of saturated fatty acids (SFAs). PUFA content was highest in small-sized hilsa; however, ω-3 PUFA content was lower and SFAs content was higher than medium-sized fish. In large-sized fish, although ω-3/ω-6 ratio was highest, quantitatively they contained the lowest amount of PUFAs and highest amount of SFAs. Thus, on basis of fatty acid profiles, medium-sized hilsa is the best followed by the small-sized fish for human health and nutrition.

A 307 bp segment of Cytochrome b gene of mtDNA was sequenced and analyzed for 90 individuals of Cirrhinus mrigala collected across the three rivers, namely Ganges, Narmada and Brahmaputra. Analyses revealed the presence of 14 haplotypes with haplotype diversity (h) ranging from 0.304 to 0.692, and nucleotide diversity (π) 0.002–0.043. The majority of variation was found within the population (96.21%), and the FST value (0.035) as well as the value of exact test of population differentiation (0.893) were found to be insignificant (p

Halomonas salina strain CIFRI1 is an extremely salt-stress-tolerant bacterium isolated from the salt crystals of the east coast of India. Here we report the annotated 3.45-Mb draft genome sequence of strain CIFRI1 having 86 contigs with 3,139 protein coding loci, including 62 RNA genes.

Halomonas salina strain CIFRI1 is an extremely salt-stress-tolerant bacterium isolated from the salt crystals of the east coast of India. Here we report the annotated 3.45-Mb draft genome sequence of strain CIFRI1 having 86 contigs with 3,139 protein coding loci, including 62 RNA genes.

The complete mitogenome of Heteropneustes fossilis is described using Ion Torrent (PGM sequencer), which showed it was 16,489 bp in size comprising 13 mRNAs, 22 tRNAs, 2 rRNA genes, and 858 bp as D...

In the present study, the complete mitochondrial genome sequence of Anabas testudineusis reported using PGM sequencer (Ion Torrent, Life Technologies, La Jolla, CA). The complete mitogenome of climbing perch, A. testudineusis obtained by the de novo sequences assembly of genomic reads using the Torrent Mapping Alignment Program (TMAP), which is 16 603 bp in length. The mitogenome of A. testudineus composed of 13 protein- coding genes, two rRNA, and 22 tRNAs. Here, 20 tRNAs genes showed typical clover leaf model, and D-Loop as the control region along with gene order and organization, being closely similar to Osphronemidae and most of other Perciformes fish mitogenomes of NCBI databases. The mitogenome in the present study has 99% similarity to the complete mitogenome sequence of earlier reported A. testudineus. The phylogenetic analysis of Anabantidae depicted that their mitogenomes are closely related to each other. The complete mitogenome sequence of A. testudineus would be helpful in understanding the population genetics, phylogenetics, and evolution of Anabantidae.

In the present study, the complete mitochondrial genome sequence of Labeo gonius is reported using PGM sequencer (Ion Torrent). The complete mitogenome of L. gonius is obtained by the de novo sequences assembly of genomic reads using the Torrent Mapping Alignment Program (TMAP) which is 16 614 bp in length. The mitogenome of L. gonius comprised of 13 protein-coding genes, 22 tRNAs, 2 rRNA genes, and D-loop as control region along with gene order and organization, being similar to most of other fish mitogenomes of NCBI databases. The mitogenome in the present study has 99% similarity to the complete mitogenome sequence of Labeo fimbriatus, as reported earlier. The phylogenetic analysis of Cypriniformes depicted that their mitogenomes are closely related to each other. The complete mitogenome sequence of L. gonius would be helpful in understanding the population genetics, phylogenetics, and evolution of Indian Carps.

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