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
A 15‐day trial was conducted to determine the effect of dietary potassium on the requirement of aqueous potassium in P. vannamei under inland saline water (ISW). Two experimental diets viz. control ...(C) and control with 1% KCl (K) were fed to P. vannamei as six treatments viz. FW (reared in freshwater and fed on C), ASW (reared in artificial seawater and fed on C), ISW (reared in inland saline water and fed on C), ISW+eK (reared in potassium fortified ISW and fed on C), ISW+fK (reared in ISW and fed on K) and ISW+½eK+fK (reared in 50% K fortified ISW and fed on K). The samples were collected on selected intervals (0th day, 1st day, 7th day and 15th day), and mortality was recorded continuously. Total mortality (100%) was observed in FW and ISW. 100% survival was recorded in ASW and ISW+½eK+fK, while a lower survival was observed in ISW+fk. The haemolymph osmotic and ionic concentrations were lowest in FW and ISW. The principal ions (Na+, K+ and Cl−) and osmolality of ISW+½ eK+fK were restored to the level of ASW within 15 days. Na+K+ATPase activity was increased in ISW while lowered by K supplementation. HSP70 expression was upregulated in ISW fortified with K partially or entirely. However, the groups reared in ISW and ISW supplemented with feed potassium alone could not enhance HSP protection up to the level of ISW+eK and ISW+½ eK+fK groups. Overall, 50% of aqueous potassium can be compensated with 1% dietary KCl, without affecting survival and ionic homeostasis.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The innate immune signaling adapter, Mitochondrial antiviral signaling protein (MAVS) coordinates the signals received from two independent RLRs (RIG-1 and MDA5) to induce IFN & interferon ...stimulatory genes (ISGs). In the present study, we report identification of an orthologue of MAVS from Lates calcarifer (LcMAVS) and its functional role in piscine RLR signaling. The LcMAVS-cDNA was cloned into pcDNA and transfected into SISS cells. LcMAVS was detected to be a 61KDa protein in western blot. Confocal microscopy demonstrated the mitochondrial localization of LcMAVS. In addition, pcDNA-MAVS transfected cells were protected against Nervous Necrosis Virus (NNV) infection as manifested by the delayed appearance of cytopathic effect (CPE) and decreased viral transcript levels. Ectopic expression of LcMAVS resulted in activation of an ISRE-containing promoter (52 folds over control cells) as well as transcriptional expression of IRF-3, IFN-1 and IFN-inducible genes including Mx and ISG15 (p<0.05). These results suggest that LcMAVS is involved in the antiviral immunity as one of the adaptors in fish IFN-activation pathway.
•The 61kDa MAVS orthologue from Asian seabass conferred its localization to mitochondria.•Ectopic expression of LcMAVS demonstrated a potent antiviral activity against NNV causing the viral RDRP transcription.•MAVS over expression increased the activity of ISRE promoter in vitro by 52 folds.•LcMAVS transient over expression triggered IFN stimulatory genes viz, IRF-3, ISG-15, and Mx.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Ribonucleic acid interference (RNAi), a valuable tool for manipulating gene functionality in the laboratory, has also emerged as a powerful tool to suppress infection or replication of many pathogens ...that cause severe economic losses in fish farming. By taking advantage of the cell’s endogenous RNAi apparatus, small interfering RNA of ~21-22 bp can be introduced into cells to induce target specific mRNA degradation. With the growing appreciation for the potential of RNAi technology, the diversity in vivo relevance to aquaculture is seemingly vast. Studies in the future should address the hurdles like delivery strategy stability and degradation of RNAi therapeutic molecule by nucleases in aquatic animals. In this article, we review the literature in the field of RNAi technology in aquaculture, summarize the status and prospects, which may open doors to its applicability potential as a therapeutic strategy to modulate host-pathogen interactions and inspire further trials.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Peptidoglycan recognition proteins (PGRPs) function in host antibacterial responses by recognizing bacterial peptidoglycan (PGN). In the present study, a short pgrp5 (named mpgrp5) was identified in ...Cirrhinus mrigala (mrigal). The full-length cDNA of the mpgrp5 gene was 1255 bp, containing an open reading frame of 746 bp encoding a protein of 248 amino acids. The predicted protein contained the typical Pgrp/amidase domain, conserved Zn
, and PGN binding residues. The phylogenetic analysis revealed that the mpgrp5 is closely related to Pgrps reported in Labeo rohita, Cyrinus carpio, and Ctenopharyngodon idella. The ontogenetic expression of mpgrp5 was highest at 7 days post-hatching (dph) and its possible maternal transfer. mpgrp5 was constitutively expressed in all tissues examined, with the highest expression observed in the intestine. Furthermore, mpgrp5 was found upregulated in mrigal post-challenge in a time-dependent manner at 6hpi in the liver (3.16 folds, p < 0.05) and kidney (2.79 folds, p < 0.05) and at 12hpi in gill (1.90 folds, p < 0.01), skin (1.93 folds, p < 0.01), and intestine, (2.71 folds, p < 0.05) whereas at 24hpi in spleen (4.0 folds, p < 0.01). Our results suggest that mpgrp5 may play an important role in antibacterial immune response from early life stages in mrigal.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Galectin-9 is a b-galactoside-binding tandem repeat galectin that regulates many cellular functions, ranging from cell adhesion to pathogen recognition. In spite of extensive study of mammalian ...galectin importance in immune system, little is known about that of fish. To study the normal expression and immune response of Labeo rohita to pathogens, a tandem-repeat galectin-9 from Labeo rohita was identified and named LrGal-9. Its full-length cDNA was 1534 bp encoded 291 amino acids (35.12 KDa), shared the highest 81% identity with the galectin-9 of Danio rerio. LrGal-9 identified in this study lacked signal peptide and a transmembrane domain like galectin-9 members reported in other fishes. Quantitative PCR showed that LrGal-9 was lowly expressed in gill, muscle, heart, highly expressed in tested immune tissues (intestine, kidney, liver, spleen) in normal body. After Aeromonas hydrophila challenge, LrGal-9 was remarkably increased in all tested immune tissues in a time-dependent manner. These results suggest that LrGal-9 plays a role in innate immunity in Labeo rohita.
•Expression and immune response of L. rohita to pathogens, a tandem-repeat gal9 was identified and named LrGal-9.•LrGal-9 was lowly expressed in gill, muscle, heart and highly expressed in intestine, kidney, liver and spleen.•LrGal-9 plays an important role in innate immunity in Labeo rohita.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Interferon regulatory factor (IRF) 3 and IRF7 are key regulators of type I interferon (IFN) gene expression for the antiviral immune response. In the present study, interferon regulatory factor 3 and ...7 from Asian seabass, namely AsIRF3 and AsIRF7 were cloned and characterized. The full-length cDNA sequence of IRF3 and IRF7 consisted of 2965 and 2343 bp respectively. AsIRF3 and AsIRF7 were true orthologes of vertebrate IRF3/7 and showed similar domain organization, with an N-terminal DBD which consisted five tryptophan residues in IRF3 and four in IRF7, a C-terminal IRF3 domain and a serine rich region. Both IRF3 and 7 constitutively expressed during the ontogenesis and in all tissues of healthy fish. The expression of both genes was up-regulated following NNV challenge with obvious transcript abundance in brain heart and kidney. Ectopic expression of AsIRF3 and AsIRF7 displayed activation of ISRE/NF-κB promoters and modulation of interferon, ISGs and pro-inflammatory cytokine gene expression. These observations indicated that IRF3 and IRF7 play an important role in Asian seabass's antiviral defense and the RIG-IRF-IFN axis is conserved in the species.
•The 61 kDa MAVS orthologue from Asian seabass conferred its localization to mitochondria.•Ectopic expression of LcMAVS demonstrated a potent antiviral activity against nervous necrosis virus causing the viral RDRP transcription.•MAVS over expression increased the activity of ISRE promoter in vitro by 52 folds.•LcMAVS transient over expression triggered IFN stimulatory genes viz, IRF-3, ISG-15, and Mx.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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