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Not AvailableTilapia, Oreochromis mossambicus, held in sea water, was experimentally infected with Aeromonas hydrophilla (SAH 93) via intramuscular injection. The pathogen has an LD of 10 CFU/fish produced characteristic ulceration leading to open wounds. More than 80 per cent of the experimentally infected fish, injected with the doses higher than LD50, died within eight days. Dermal necrosis and liquifying muscular degeneration with infiltration of cellular serum factors to the site of injection were noticed. Focal necrosis of the hepatocytes, tubular degeneration and sloughing, glomerular necrosis, necrosis and depletion of the cells in the renal tubular interstitia, loss of sub-mucosa and sloughing of the intestinal microvilli were the major histopathological manifestations of the experimental infection. Aggregation of macrophages and melano macrophage centres (MMC) in the head kidney and spleen were also noticed. Gill lamellar basement epithelium showed mid hyperplasia and hypertrophy. Lifting and seperation of the epithelium of the secondary lamellae and arterial congestion in the primary lamellae were observed as delayed responses. The study indicated that Tilapia could be a potential carrier of A. hydrophila, and thus, has to be used with caution as a forage fish.Not Availabl

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Not AvailableWhite spot syndrome virus (WSSV) is one of the most devastating pathogens, which inflicted huge losses to the shrimp farming sector in India and the world. The current study maps the WSSV research output during 1998–2017 using Web of Science (WoS) database. A total of 1786 tags were subjected to the present analysis which covers various parameters viz., growth, rank and global publications share, research collaborations and other bibliometric indicators like total citation counts, average citations per paper, and h-Index. India accounted for 17.24% of the global WSSV publications, and stood second among the 15 most productive countries in terms of number of publications in this period. The Indian researchers had networked with 23 collaborating partners across the world, of which USA, the lead collaborating country accounted for 18.51% of the total papers with international collaboration. The study showed a positive correlation between the grants awarded to the research laboratories and their research productivity. The paper provides quantitative analysis on the leading institutions and individual researchers, significantly contributing to the WSSV research in India. The journal Aquaculture carried the maximum number of research papers on WSSV from India (53 papers), followed by Fish and Shellfish Immunology (32 papers) and Diseases of Aquatic Organisms (25 papers). The analytical results of the present study provide insights into the trends of WSSV research in India and calls for concerted efforts to enhance focussed research on this significant threat to the 4.8 billion USD worth shrimp farming sector, which has the potential to reverse the fortunes of the farmers.Indian Council of Agricultural Research (ICAR), New Delh

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Not AvailableA new myxosporean, Myxobolus etroplisp. nov., was found to infect the bulbus arteriosus of Etroplus suratensis (Bloch) from brackishwater lagoons of Muttukkadu, Chennai coast, India. A survey from May 1993 to October 1994 revealed a prevalence rate of 33.7% of this parasite. Macroscopic discoloured foci/cysts were seen in the bulbus arteriosus of the fish. The parasite showed strict host and site specificity. Histopathology showed that the infection was restricted to the bulbus. This isthe first report of a myxosporean from E. suratensisNot Availabl

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Not AvailableA captive broodstock of the grey mullet Mugil cephalus has been successfully developed at Muttukadu experimental station of the Central Institute of Brackishwater Aquaculture. A stock of 72 sub-adult and adult fish in the size range of 290-450 mm/300-1,200 g procured from the commercial catches were maintained in 100 tonne capacity RCC tanks hom January '96. During 1996, about 20% of the stock, both males and females attained final maturity. In 1997, about 60% of the females and 80% of the males attained final maturity In mature females ova diameter of the matured oocytes ranged from 525 to 614 pa and the mature males were in oozing stage.Not Availabl

Aquaculture

Not AvailableDactylogyrus is one of the major parasites ubiquitously present in the aquatic environment causing severe eco-nomic loss. The present study documented a new species of Dactylogyrus from India infecting the Indian major carp, i.e. rohu (Labeo rohita) both in natural and experimental conditions. The 18 s and 28 s rDNA sequence analyses revealed the present isolate of having 99.29% and 96.21% sequence homology, respectively with D. scorpius belonging to African Dactylogyrus lineage III. A co-habitational challenge study further confirmed that catla (Catla catla) and mrigal (Cirrhinus mrigala), two other species of Indian major carps, were resistant to this parasite in a 20-day infection trial. On the other hand, co-habitational challenge study showed 100% prevalence in rohu from 1-day post-infection (dpi) onwards with a gradual increase in average parasitic load of 4.8, 40.84, 61.50, 91.20 and 81.40 numbers on 1, 3, 5, 10 and 20 dpi of sampling, respectively. This study forms the first report of D. scorpius infection in India and rohu was found to be the preferred host of this parasite. The gill tissues collected from rohu fingerlings at the above time points were also subjected to expression analysis of different immune-related genes viz., genes involved in specific immunity (IgM, IgZ, MHC I), recognition molecule (TLR 22), pro-inflammatory cytokines (IL-1?, IL-6, IL-8, IL-15, TNF ?), anti-inflammatory cytokine (IL-10), antioxidant molecules (MnSOD, GPx, catalase) and antimicrobial peptides (apolipoprotein A-I, lysozyme G). A significant up- regulation of all immune-related genes except MHC I and IL-15 was observed in gill tissues of infected rohu at different time points, thus indicating the role of both specific and non-specific immune responses against D. scorpius infection. The progressive rise in parasitic load in gill tissues corresponding to days of infection clearly indicated immune evasion mechanism for its co-existence in the advent of up-regulation of an array of immune- related genes in the host. The results obtained in this study could be useful for understanding host-pathogen interaction and further development of any prophylactic measures against this important parasite

Aquaculture

Not AvailablePolymeric immunoglobulin receptor (pIgR) is a protein that transports Immunoglobulins (Igs) from epithelial cells into the external secretion system of the animal. In the present study, we characterized the partial pIgR gene from Labeo rohita and analyzed its expression in response to the pDNA (pGPD-IFN) vaccine, and studied its correlation with the expression of IgM, in the mucosal-associated lymphoid tissues (MALT). The significant (p < 0.05) up-regulation of pIgR mRNA was observed in the mucosal tissues of vaccinated fish by qRT-PCR. The highest expression of the gene was detected in gill tissue at 15 days post-vaccination (dpv) followed by skin and gut at 30 dpv. The expression of IgM also showed a similar pattern and indicated a direct correlation of pIgR expression in all the tested tissues. The protective immune response of the DNA vaccine was measured as the relative percentage of survival (RPS) by challenging vaccinated fish with live Edwardsiella tarda (1 ? 105 CFU/Fish). The result showed a significantly high relative percentage survival (RPS) in the vaccinated group (47.05%) compared to the control group. Many factors contributing to the immune response of the vaccine. One of the most critical aspects is the rise in IgM level in local tissues. In other higher vertebrates, pIgR is reported to act as the transporter of IgM. The positive correlation in the expression of pIgR and IgM observed in the present study demonstrated the possible role of pIgR as the transporter of IgM in L. rohita. The study suggests the possibility of the secretory nature of IgM in fish

Aquaculture International

Not AvailableTilapia lake virus (TiLV) is a serious pathogen of farmed Nile tilapia (Oreochromis niloticus) responsible for significant mortalities. In this study, we investigated a disease outbreak in cage-farmed Nile tilapia in India. The infected fish exhibited clinical signs such as severe scale loss, haemorrhage, exophthalmia, and fin and tail rot. The samples were screened for Tilapia lake virus (TiLV) by reverse-transcriptase PCR and also subjected to detailed bacteriological investigation to understand the association between TiLV and co-infecting bacterial pathogens. Bacteria were isolated from TiLV-infected and apparently healthy fish, and identified by conventional microbiological methods, followed by 16SrRNA gene sequencing. TiLV was detected by PCR in all the samples exhibiting clinical signs, while apparently healthy fish were negative for the virus. A total of 34 bacterial isolates belonging to the genera Aeromonas, Staphylococcus, Enterococcus, Plesiomonas, Enterobacter, Bacillus, Lysinibacillus, Solibacillus and Exiguobacterium were isolated from the virus-infected tilapia. However, Aeromonas veronii was found to be the most dominant bacterium isolated from the surface lesions and the internal organs of all infected fish. Antibiotic susceptibility testing revealed that A. veronii, by far, was susceptible to cephalosporins (ceftriaxone, cefotaxime, cefpodoxime), chloramphenicol, aminoglycosides (amikacin, gentamicin), ciprofloxacin and chloramphenicol. Experimental infection using intraperitoneally injected A. veronii reproduced the clinical signs of naturally infected Nile tilapia, and a lethal dose 50 (LD50) mortality was observed by day 7 post-challenge. Furthermore, A. veronii could be re-isolated from the experimentally infected fish. Based on this evidence, we propose that virulent A. veronii as a co-infecting bacterium can have an important role in the severity and outcome of the disease in Nile tilapia infected by TiLV

Fish and Shellfish Immunology

Not AvailableRohu (Labeo rohita), an Indian Major Carp (IMC) is an economically important aquaculture species in India. Inspite of the technological advances, infectious diseases caused by viruses, bacteria and parasites have been a major limiting factor in the development and profitability of fish farms. At present, information regarding the immune status of the Indian major carps is limited. This lack of knowledge is a major impediment for establishment of effective preventive measures against broad spectrum of infectious agents. The present study was undertaken to examine the modulation of few immune-regulatory genes: IgHC, NOD 1, TLR 22, iNOS and IL-1? during experimental infection of E. tarda in L. rohita to understand their role in pathogenesis. Rohu fingerlings were intra-peritoneally injected with Edwardsiella tarda (LD50 dose of 8.7 ? 104 CFU/fish) and sampled for three immunologically important organs (kidney, liver and spleen) at different time intervals (zero hour or pre-challenge and 6 h, 12 h, 24 h, 48 h and 96 h post challenge). For absolute quantification of genes by real time RT-PCR, all the genes transcript were amplified from Poly I:C induced rohu lymphocytes and cloned in pTZ57R/T plasmid. Standard curves for each gene was generated from serially diluted plasmid bearing respective genes. Evaluation of copy number of different genes present in the tissue showed that the expression of IgHC, iNOS and IL-1? was highest in kidney followed by spleen and least in liver. While for NOD 1 and TLR 22 gene, liver showed higher expression than kidney and spleen. Further, the expression of IgHC, INOS, TLR 22, NOD 1 and IL-1? genes significantly differed (P < 0.05) in the E. tarda challenged fish when compared with pre-challenged control fish. Among the five genes we studied, the basal expression of TLR 22 gene was highest. The result also depicts that iNOS and NOD 1 are immediate responsive genes as their expression reached maximum level at 6?24 h post infection (hpi) after which the expression declined. In contrast, TLR 22 and IgHC gene transcript showed enhanced expression during the late phase of with maximum expression observed after 48 hpi and 96 hpi respectively. IL-1?, being the exception, showed high expression both at 24 hpi and 96 hpi. From this study, we conclude that these five immune genes have a definite role to play in the defense mechanism of host (L. rohita) against E. tarda

Fish and Shellfish Immunology

Not AvailableImmunoglobulin (IgM) is the primary immunoglobulin essential for defense mechanisms in fish. It is difficult to reliably quantify IgM because a lack of standardization in methodology and limited availability of commercially reagents. In the present study, a polyclonal antibody was developed for the specific detection and quantification of IgM in Labeo rohita. Recombinant bicistronic NanoDNA plasmid (RBND Vac) encoding the glyceraldehyde - 3 - phosphate dehydrogenase gene of Edwarsiella tarda conjugated with poly (lactic - co - glycolic acid) - Chitosan (PLGA - Chit) was developed and its potential as a DNA vaccine, to prevent the infection of E. tarda in L. rohita was investigated. Two treatment groups [T1 - (PLGA - Chit - NPs - pDNA), T2 - (PLGA - NPs - pDNA) and one control group (T0 - 1 PBS)] were utilized. Polyclonal antibody was developed to estimate IgM titers in the serum and mucosal associated tissues (MAT) using Enzyme-linked Immunosorbent Assay (ELISA) technique. Additionally, immune gene expression was studied using qRT - PCR. Vaccinated groups also exhibited a significant increase in the total serum protein, globulin concentration and relatively less mortality was observed in T1 group. IgM level in serum and mucosal tissues (skin, gill and gut) increased significantly days post vaccination compared to control group, also non-specific immune parameters (myeloperoxidase and lysozyme levels) showed significant improvement in vaccinated fish. Furthermore, histopathological examination confirmed minor damage in physiological structure of kidney and liver tissues in vaccinated fish. Knowledge of the immunoglobulin in L. rohita primed with RBND Vac complex provides the better protection against E. tarda. The normal physiology findings of this study will aid in monitoring changes in the health status of fish, when the animals undergo vaccination by immersion method

International Journal of Biological Macromolecules.

Not AvailableDNA vaccine is an important tool to elicit both humoral and cellular immunity. Present study investigates mucosal immune response of Labeo rohita (15 ? 04 g) to plasmid DNA (pDNA) vaccine macromolecule complexed with nanoparticles (NPs). Poly lactic-co-glycolic acid (PLGA), Chitosan (Chit) and PLGA-Chit-NPs were synthesized by double emulsion solvent evaporation method. Synthesized NPs were complexed with pDNA (pGPD + IFN) vaccine construct. Size and zeta potential of PLGA-NPs, Chit-NPs and PLGA-Chit-NPs-pDNA complex were recorded to be 120 nm and +0.5 mV, 117 nm and +32 mV, 189 nm and +11 mV, respectively. Immunization by immersion was carried out in two groups receiving PLGA-Chit-NPs-pDNA (T1) and PLGA-NPs-pDNA (T2) respectively. After immersion, samples were collected on 0, 2, 4, 7, 15 and 30 days from mucosa-associated lymphoid tissues (MALT) for mRNA expression studies of IgM, IgD and IgZ using qRT-PCR. Significant up-regulation of the mRNA expression of IgM, IgD, and IgT were observed in MALT in immunized fish compared to control. After 30 days post-immunization fish were infected with a virulent strain of Edwardsiella tarda. The highest relative percentage survival was observed in T1 (64.7%) compared to T2. The study showed better efficiency of pDNA-PLGA-Chit-NPs compared to pDNA-PLGA-NPs for inducing adaptive mucosal immunity in fish