Multi-drug resistance (MDR) in bacteria is regarded as an emerging pollutant in different food production avenues including aquaculture. One hundred and sixty out of 2304 bacterial isolates from ...shrimp farm samples (
n
= 192) of Andhra Pradesh, India, were MDR. Based on biochemical identification and 16S rRNA sequencing, they were grouped into 35 bacterial species with the predominance of
Vibrio parahaemolyticus
(12.5%). The MDR isolates showed highest resistance toward oxytetracycline (89%) with more than 0.2 MAR (multiple antibiotic resistance), demonstrates a high-risk source. The most prevalent antibiotic-resistance gene (ARG) and mobile genetic element (MGE) detected were
tetA
(47.5%) and
int1
(46.2%), respectively. In conjugation experiments, overall transfer frequency was found to be in the range of 1.1 × 10
−9
to 1.8 × 10
−3
with the transconjugants harbouring ARGs and MGEs. This study exposed the wide distribution of MDR bacteria in shrimp and its environment, which can further aggravate the already raised concerns of antibiotic residues in the absence of proper mitigation measures.
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Parasitic diseases have been the major source of concern and cause considerable losses in the freshwater aquaculture of India. Fish parasites proliferate quickly in favourable settings, compromising ...fish health and frequently resulting in high mortality. Identifying and implementing appropriate control techniques is the need of the hour to combat the diseases. Emamectin benzoate (EMB) is an efficient infeed therapy for ectoparasite control in fish. The aim of the present study was to determine the withdrawal period of EMB in silver carp (Hypophthalmichthys molitrix) commercially important fish species in southeast Asia. The depletion of EMB residues in silver carp muscle treated with a dose of 50 μg kg−1 body weight (BW) day−1 for seven consecutive days was assessed. Muscle tissue was sampled on the 7th day of EMB feeding and 1st‐, 3rd‐, 7th‐, 14th‐, 21st‐, 35th‐ and 41st‐day post‐medication (PM) for QTRAP 4000 LC–MS/MS analysis. The data revealed that the level of EMB in the fish muscle was 13.0 ± 0.1 parts per billion (ppb) on the 0th day of withdrawal. The residue levels were reduced significantly on the 3rd day, with traces of EMB recorded by 21st‐day PM and reached undetectable levels by 31st day PM. Considering the maximum residue limit (MRL) of 100 μg kg−1 for fish muscle, the present study's findings support the usage of EMB in silver carp under the conditions employed in the study. The current study provides crucial information on the use of EMB as an antiparasiticide in silver carp, considering the food safety issues.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Emerging and re-emerging diseases in fish cause drastic economic losses in the aquaculture sector. To combat the impact of disease outbreaks and prevent the emergence of infections in culture ...systems, understanding the advanced strategies for protecting fish against infections is inevitable in fish health research. Therefore, the present study aimed to evaluate the induction of trained immunity and its protective efficacy against Streptococcus agalactiae in tilapia. For this, Nile tilapia and the Tilapia head kidney macrophage primary culture were primed using β-glucan @200 μg/10 g body weight and 10 μg/mL respectively. Expression profiles of the markers of trained immunity and production of metabolites were monitored at different time points, post-priming and training, which depicted enhanced responsiveness. Higher lactate and lactate dehydrogenase (LDH) production in vitro suggests heightened glycolysis induced by priming of the cells using β-glucan. A survival rate of 60% was observed in β-glucan trained fish post challenge with virulent S. agalactiae at an LD50 of 2.6 × 107 cfu/ml, providing valuable insights into promising strategies of trained immunity for combating infections in fish.
•Innate immune training using β-glucan can elevate cytokine transcript levels.•Expression of trained immunity markers, mTOR and HIF1α elevated post immune training with β-glucan in tilapia.•Higher lactate and LDH production post β-glucan induction in the supernatant of tilapia head kidney macrophage culture.•Survival rate of 60% in Streptococcus agalactiae-challenged immune trained tilapia.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Mitochondrial antiviral signaling protein (MAVS), an innate immune signaling adapter coordinates the signals received from two independent cytosolic pathogen recognition receptors (RIG-1 and MDA5) to ...induce antiviral genes. In the present study the MAVS gene of Lates calcarifer (LcMAVS) was cloned and characterized. The complete cDNA sequence of LcMAVS was 3160 bp and encodes a poly peptide of 577 amino acids. Structural analysis of LcMAVS revealed an N-terminal CARD-like domain, central proline-rich domain and a C-terminal transmembrane domain. Phylogenetic analysis indicated that LcMAVS exhibited the closest relationship to P. olivaceous MAVS. LcMAVS was ubiquitously expressed in all tested tissues of healthy fish viz., brain, gill, heart, liver, spleen, kidney and intestine, with highest transcript level in spleen. The mRNA transcript level of LcMAVS in different developmental stages showed constitutive expression in all the stages tested suggesting the maternal transfer of the gene. Significant up regulation in MAVS expression was observed post nervous necrosis virus (NNV) challenge in vivo in all the selected tissues. Further, time course analysis showed that LcMAVS transcripts significantly increased in the brain and spleen tissues after NNV infection. These findings provide useful information for further elucidating the function of LcMAVS in antiviral innate immune response against NNV in Asian seabass.
•The MAVS gene of Lates calcarifer (LcMAVS) was cloned and characterized.•Phylogenetic analysis indicated that LcMAVS exhibited the closest relationship to P. olivaceous MAVS. LcMAVS was ubiquitously expressed in all tested tissues of healthy fish viz., brain, gill, heart, liver, spleen, kidney and intestine, with highest transcript level in spleen.•The mRNA transcript level of LcMAVS in different developmental stages showed constitutive expression in all the stages tested suggesting the maternal transfer of the gene.•The time course analysis showed that LcMAVS transcripts significantly increased in the brain and spleen tissues after NNV infection.•The findings provide useful information for further elucidating the function of LcMAVS in antiviral innate immune response against NNV in Asian seabass.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The morphometric and carcass quality changes associated with the compensatory growth of stunted fish in optimum culture condition differentiate the quality of poststunted fish from normal fish. This ...study compared carcass quality characteristics data on poststunted and normal milkfish of marketable size reared under pond culture conditions. The cultured fish samples of poststunted and normal milkfish (of average weight 420–500 g) were collected from the brackish water fish farm at ICAR‐Central Institute of Fisheries Education, Kakinada, Andhra Pradesh, India. Fish stunted for 8 months were further reared for a period 8 months (poststunting), whereas normal fish were reared at the optimal condition for 16 months followed by an assessment of carcass quality characteristics such as morphometric, offal, carcass filleting traits and carcass proximate composition. The results showed higher dressed carcass traits such as dressed (85.42%), headless dressed (66.92%) and skinless dressed percentage (65.69%) in poststunted fish than the normal fish. However, the study did not find any significant difference in offal and dressed carcass trait yields. The fillet cutability traits found a higher percentage of meat (64.40%) and lower bone content (14.19%) in poststunted fish. This study recorded higher meat percentage in mid cut followed by fore and hind cuts in both groups of fish. The proximate composition of fillet cuts showed significant differences in moisture, dry matter, protein and fat content between normal and poststunted fish. Further, the study proved that nutrient accretion and deposition vary considerably among body components of fish during the compensatory growth phase. Overall, the results of this study suggested that poststunted fish are more nutritious and yield better fillets concerned with processing efficiency and nutritional quality for consumers than normally reared milkfish.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
TLR5 is one of the important PRR (pathogen recognition receptors) and plays a fundamental role in pathogen recognition and activation of innate immune responses. It recognizes bacterial flagellin and ...stimulates the production of proinflammatory cytokines, through signalling via the adaptor protein MyD88. In this study, we characterized partial TLR5 (soluble form) gene from Pangasianodon hypophthalmus and analysed its expression profile upon challenge by Edwardsiella tarda. Bioinformatic analysis of gene sequence revealed a putative protein of 266 amino acids with four Leucine rich repeats. Quantitative expression analysis of TLR 5S showed its wide distribution in various organs and tissues. However, significant expression of TLR5S was observed in liver and spleen at 12 h (∼207.8 fold, p < 0.05). Significant upregulation was observed in kidney at 72 h.p.i. (50 folds, p < 0.05) indicating that the kidney provides longer protection almost till the activation of the adaptive immune system. This study enriches the knowledge of TLR5S in boosting the innate immunity against bacterial invasion in fish.
•We identified and partially characterized the Toll like receptor 5 in P. hypophthalmus.•The catfish TLR 5 gene is variously expressed in different immune organs at different time intervals against E. tarda infection.•We studied histopathological changes in various tissues of catfish against E. tarda infection.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The synthesis of silver nanoparticles has gained interest due to their diverse applications in various fields. It is very essential to use capping agents to avoid loss of nanosized characteristics ...due to agglomeration of AgNPs. In the present investigation, a simple and environmentally viable protocol to synthesize a wide range of concentrations of non-agglomerated and colloidal AgNPs using extracts of discarded wastes (gills and intestine) of Tilapia (Oreochromis mossambicus) in three different aqueous media without the requirement of any additional stabilizing and capping agent is described. The size of most of AgNPs ranged from 2 to 20 nm, followed by sizes of 20-40 nm and some with sizes of 40-50 nm. Zeta potential was in the range of −31.1 to −52.8 mV and −33.3 to −53.6 mV, and surface plasmon resonance ranged from 405 to 410 nm for gill and intestine extracts respectively. HR-TEM images indicated that Phosphate buffer saline is the best suitable for synthesizing non-agglomerated AgNPs capped with biomolecules. Valorization has been achieved by trapping Ag NPs into two different forms of natural zeolites namely stilbite and mordenite and their ammonia removal efficiency have been evaluated. In addition, the antimicrobial activity of synthesized AgNPs and their valorized products exhibited potent inhibitory activity against test bacteria such as Escherichia coli and Aeromonas hydrophila. This study not only establishes a simple and environmentally viable protocol for the synthesis of AgNPs and valorized products for environmental and disease management but also adds to the utilization of fish wastes in solid waste management.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
A 60‐day feeding experiment was conducted to evaluate the dietary effect of vitamin C on non‐specific immunity and stress responses in striped catfish, Pangasianodon hypophthalmus juveniles with the ...average body weight of 3.23 ± 0.01 g to 3.38 ± 0.01 g. Seven graded levels of diets supplemented with 0, 17.5, 35, 70, 175, 350 and 700 mg vitamin C/kg diet as L‐ascorbyl‐2‐polyphosphate were fed to fish in triplicates group. At the end of the experiment, fish fed vitamin C diet had significantly higher responses for nitroblue tetrazolium (NBT), serum lysozyme, phagocytic activities and lowest activities for superoxide dismutase (SOD) and catalase (p<0.05) under both pre‐ and post‐challenge conditions with Aeromonas hydrophila. After a challenge, the percentage survival of fish fed vitamin C diet was improved than those of fish fed vitamin C‐deficient diet. The overall results of the present study indicated that dietary vitamin C had a significant influence on immunity and stress mitigation in P. hypophthalmus juveniles. However, the highest positive response values obtained for immune and stress parameters in fish lies within the range of 350 to 700 mg ascorbic acid (AA) kg−1 of the diet. From the present experiment, it may be concluded that the dietary vitamin C supplementation at the level of 350 to 700 mg AA kg−1 of the diet would be optimal for influencing the immunity and stress responses in P. hypophthalmus juveniles.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
