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Papers by Hemanta Pokhrel

Journal of entomology and zoology studies, Sep 1, 2018

High incidence of mortality in fish was recorded due to Aeromonas infection in carp culture syste... more High incidence of mortality in fish was recorded due to Aeromonas infection in carp culture system in the central valley of Brahmaputra region, Assam. Infected fish showed mostly gross ulcerative lesion on the skin with erosion of scales and fin and tail rot. Aeromonas hydrophila was dominant among the isolated bacteria from kidney, liver and skin of infected fish. Experimental infection in L. rohita with isolated A. hydrophila showed clinical signs with weakness, anorexia, swimming closer to surface, darkness in color with hyperemia and lysis of the fins. While, fluid accumulation in the abdomen, swollen liver, spleen and kidney with clear histopathological alterations were visible internally in moribund fishes. The study indicates that A. hydrophila is capable of causing pathological changes indifferent organs in L. rohita and cause mortality of affected fish in culture systems.

Journal of Applied Ichthyology

Appearance, development and organization of Melano-Macrophage Centres (MMCs) in Indian major carp... more Appearance, development and organization of Melano-Macrophage Centres (MMCs) in Indian major carps. (Catla catla, Labeo rohita and Cirrhinus mrigala) was studied for a period of 360 days. Small patches of melanin-containing cells appeared at about 60 days old in the spleen and kidney of these species. The density of splenic and renal MMCs was observed to increase steadily with age of the fish. The MMCs were less compact and smaller in size in the trunk kidney than in the spleen. The size of the MMCs was highly variable within the fish in the same organ and these centres were distributed in the spleen, pronephros, and mesonephros and opisthonephros but not observed in the liver and thymus in the species. The existence of morphological similarity was observed with respect to size, shape and distribution of MMCs in all the three species of Indian major carps.

Indian Journal of Animal Research, 2021

Background: Imidacloprid (IMI) belongs to the class of neuro active insecticides, used to control... more Background: Imidacloprid (IMI) belongs to the class of neuro active insecticides, used to control pest and insects in agricultural crops. Reports suggest that IMI has highly toxic consequences on bees, humans and non-targeted aquatic animals. Hence the present study aims to investigate the toxicity effects of commercial-grade Imidacloprid (IMI) (Premise, 30.5%, a.i) using histological and transcriptional changes in heat shock protein 70 (HSP70) and cytochrome P4501A(CYP1A) genes in liver and gills of non-targeted aquatic animal, Cyprinus carpio. Methods: Three different sublethal concentrations of IMI (T1=26.04 mg/L, T2= 20.38 mg/L, T3=17.36 mg/L) were selected and common carp fingerlings were exposed for 28 days where histological alterations and expression study of HSP70 and CYP1A in gills and liver of exposed fishes being studied on 7, 14, 21 and 28 days interval using standard procedure. Result: Marked histological alteration like hydropic degeneration and cellular infiltration ...

Turkish Journal of Fisheries and Aquatic Sciences

Fenpropathrin displays enduring effects on aquatic environment which can be highly toxic and accu... more Fenpropathrin displays enduring effects on aquatic environment which can be highly toxic and accumulative to non-targeted aquatic organisms like fish. While most of the previous studies focused on the toxicity of analytical grade of Fenpropathrin, insufficient attention has been paid to compare toxicity of the active ingredient (a.i) with its commercial formulation. Therefore, the present study is an attempt to evaluate the lethal as well as sublethal toxicity along with cardiac, morphological, behavioral and neurotoxic biomarker responses induced by Fenpropathrin and its commercial formulation Meothrin and Danitol on zebrafish embryos. The study reveals 96-hour (h) LC50 values that are 0.156(0.121-0.202), 0.953(0.736-1.248) and 1.168(0.913- 1.503) mg a.i/L; 96 h EC50 values are 0.016, 0.152 and 0.369 mg a.i/L and Teratogenic Index (TI) ratio of 9.75, 6.26 and 3.16 for Fenpropathrin, Meothrin and Danitol respectively (Fenpropathrin>Meothrin>Danitol). The reduction in toxicity ...

International Journal of Current Microbiology and Applied Sciences, Jul 10, 2018

Journal of entomology and zoology studies, 2018

High incidence of mortality in fish was recorded due to Aeromonas infection in carp culture syste... more High incidence of mortality in fish was recorded due to Aeromonas infection in carp culture system in the central valley of Brahmaputra region, Assam. Infected fish showed mostly gross ulcerative lesion on the skin with erosion of scales and fin and tail rot. Aeromonas hydrophila was dominant among the isolated bacteria from kidney, liver and skin of infected fish. Experimental infection in L. rohita with isolated A. hydrophila showed clinical signs with weakness, anorexia, swimming closer to surface, darkness in color with hyperemia and lysis of the fins. While, fluid accumulation in the abdomen, swollen liver, spleen and kidney with clear histopathological alterations were visible internally in moribund fishes. The study indicates that A. hydrophila is capable of causing pathological changes indifferent organs in L. rohita and cause mortality of affected fish in culture systems.

River Kopili, regarded as one of the most important Southern bank tributaries of the mighty river... more River Kopili, regarded as one of the most important Southern bank tributaries of the mighty river Brahmaputra, is facing a tremendous pollution threat from its riparian areas, especially in its upper stretches due to anthropogenic activities. The Central Pollution Control Board (CPCB) in one of its report has placed the Kopili river in 4th rank among the 56 most polluted river of North-East region. The results of the present study showed that water quality index [1] of the river ranges from poor to unsuitable quality of water for drinking in almost all the five sampling stations. The water quality found to be deteriorated during winter season with an average WQI value of 81.88 as compared to pre-monsoon and monsoon season with an average value of 67.13 and 80.12 respectively. According to the water quality index, station 4 and 5 are recorded to be the most polluted stations among the study area. Thus, all the above analysis showed that the riverine ecosystem is moderately polluted, ...

Journal of Applied Ichthyology

International Journal of Current Microbiology and Applied Sciences

International Journal of Current Microbiology and Applied Sciences

Indian Journal of Animal Research

Background: Imidacloprid (IMI) belongs to the class of neuro active insecticides, used to control... more Background: Imidacloprid (IMI) belongs to the class of neuro active insecticides, used to control pest and insects in agricultural crops. Reports suggest that IMI has highly toxic consequences on bees, humans and non-targeted aquatic animals. Hence the present study aims to investigate the toxicity effects of commercial-grade Imidacloprid (IMI) (Premise, 30.5%, a.i) using histological and transcriptional changes in heat shock protein 70 (HSP70) and cytochrome P4501A(CYP1A) genes in liver and gills of non-targeted aquatic animal, Cyprinus carpio. Methods: Three different sublethal concentrations of IMI (T1=26.04 mg/L, T2= 20.38 mg/L, T3=17.36 mg/L) were selected and common carp fingerlings were exposed for 28 days where histological alterations and expression study of HSP70 and CYP1A in gills and liver of exposed fishes being studied on 7, 14, 21 and 28 days interval using standard procedure. Result: Marked histological alteration like hydropic degeneration and cellular infiltration ...

International Journal of Current Microbiology and Applied Sciences

Journal of entomology and zoology studies, Sep 1, 2018

High incidence of mortality in fish was recorded due to Aeromonas infection in carp culture syste... more High incidence of mortality in fish was recorded due to Aeromonas infection in carp culture system in the central valley of Brahmaputra region, Assam. Infected fish showed mostly gross ulcerative lesion on the skin with erosion of scales and fin and tail rot. Aeromonas hydrophila was dominant among the isolated bacteria from kidney, liver and skin of infected fish. Experimental infection in L. rohita with isolated A. hydrophila showed clinical signs with weakness, anorexia, swimming closer to surface, darkness in color with hyperemia and lysis of the fins. While, fluid accumulation in the abdomen, swollen liver, spleen and kidney with clear histopathological alterations were visible internally in moribund fishes. The study indicates that A. hydrophila is capable of causing pathological changes indifferent organs in L. rohita and cause mortality of affected fish in culture systems.

Journal of Applied Ichthyology

Appearance, development and organization of Melano-Macrophage Centres (MMCs) in Indian major carp... more Appearance, development and organization of Melano-Macrophage Centres (MMCs) in Indian major carps. (Catla catla, Labeo rohita and Cirrhinus mrigala) was studied for a period of 360 days. Small patches of melanin-containing cells appeared at about 60 days old in the spleen and kidney of these species. The density of splenic and renal MMCs was observed to increase steadily with age of the fish. The MMCs were less compact and smaller in size in the trunk kidney than in the spleen. The size of the MMCs was highly variable within the fish in the same organ and these centres were distributed in the spleen, pronephros, and mesonephros and opisthonephros but not observed in the liver and thymus in the species. The existence of morphological similarity was observed with respect to size, shape and distribution of MMCs in all the three species of Indian major carps.

Indian Journal of Animal Research, 2021

Background: Imidacloprid (IMI) belongs to the class of neuro active insecticides, used to control... more Background: Imidacloprid (IMI) belongs to the class of neuro active insecticides, used to control pest and insects in agricultural crops. Reports suggest that IMI has highly toxic consequences on bees, humans and non-targeted aquatic animals. Hence the present study aims to investigate the toxicity effects of commercial-grade Imidacloprid (IMI) (Premise, 30.5%, a.i) using histological and transcriptional changes in heat shock protein 70 (HSP70) and cytochrome P4501A(CYP1A) genes in liver and gills of non-targeted aquatic animal, Cyprinus carpio. Methods: Three different sublethal concentrations of IMI (T1=26.04 mg/L, T2= 20.38 mg/L, T3=17.36 mg/L) were selected and common carp fingerlings were exposed for 28 days where histological alterations and expression study of HSP70 and CYP1A in gills and liver of exposed fishes being studied on 7, 14, 21 and 28 days interval using standard procedure. Result: Marked histological alteration like hydropic degeneration and cellular infiltration ...

Turkish Journal of Fisheries and Aquatic Sciences

Fenpropathrin displays enduring effects on aquatic environment which can be highly toxic and accu... more Fenpropathrin displays enduring effects on aquatic environment which can be highly toxic and accumulative to non-targeted aquatic organisms like fish. While most of the previous studies focused on the toxicity of analytical grade of Fenpropathrin, insufficient attention has been paid to compare toxicity of the active ingredient (a.i) with its commercial formulation. Therefore, the present study is an attempt to evaluate the lethal as well as sublethal toxicity along with cardiac, morphological, behavioral and neurotoxic biomarker responses induced by Fenpropathrin and its commercial formulation Meothrin and Danitol on zebrafish embryos. The study reveals 96-hour (h) LC50 values that are 0.156(0.121-0.202), 0.953(0.736-1.248) and 1.168(0.913- 1.503) mg a.i/L; 96 h EC50 values are 0.016, 0.152 and 0.369 mg a.i/L and Teratogenic Index (TI) ratio of 9.75, 6.26 and 3.16 for Fenpropathrin, Meothrin and Danitol respectively (Fenpropathrin>Meothrin>Danitol). The reduction in toxicity ...

International Journal of Current Microbiology and Applied Sciences, Jul 10, 2018

Journal of entomology and zoology studies, 2018

High incidence of mortality in fish was recorded due to Aeromonas infection in carp culture syste... more High incidence of mortality in fish was recorded due to Aeromonas infection in carp culture system in the central valley of Brahmaputra region, Assam. Infected fish showed mostly gross ulcerative lesion on the skin with erosion of scales and fin and tail rot. Aeromonas hydrophila was dominant among the isolated bacteria from kidney, liver and skin of infected fish. Experimental infection in L. rohita with isolated A. hydrophila showed clinical signs with weakness, anorexia, swimming closer to surface, darkness in color with hyperemia and lysis of the fins. While, fluid accumulation in the abdomen, swollen liver, spleen and kidney with clear histopathological alterations were visible internally in moribund fishes. The study indicates that A. hydrophila is capable of causing pathological changes indifferent organs in L. rohita and cause mortality of affected fish in culture systems.

River Kopili, regarded as one of the most important Southern bank tributaries of the mighty river... more River Kopili, regarded as one of the most important Southern bank tributaries of the mighty river Brahmaputra, is facing a tremendous pollution threat from its riparian areas, especially in its upper stretches due to anthropogenic activities. The Central Pollution Control Board (CPCB) in one of its report has placed the Kopili river in 4th rank among the 56 most polluted river of North-East region. The results of the present study showed that water quality index [1] of the river ranges from poor to unsuitable quality of water for drinking in almost all the five sampling stations. The water quality found to be deteriorated during winter season with an average WQI value of 81.88 as compared to pre-monsoon and monsoon season with an average value of 67.13 and 80.12 respectively. According to the water quality index, station 4 and 5 are recorded to be the most polluted stations among the study area. Thus, all the above analysis showed that the riverine ecosystem is moderately polluted, ...

Journal of Applied Ichthyology

International Journal of Current Microbiology and Applied Sciences

International Journal of Current Microbiology and Applied Sciences

Indian Journal of Animal Research

Background: Imidacloprid (IMI) belongs to the class of neuro active insecticides, used to control... more Background: Imidacloprid (IMI) belongs to the class of neuro active insecticides, used to control pest and insects in agricultural crops. Reports suggest that IMI has highly toxic consequences on bees, humans and non-targeted aquatic animals. Hence the present study aims to investigate the toxicity effects of commercial-grade Imidacloprid (IMI) (Premise, 30.5%, a.i) using histological and transcriptional changes in heat shock protein 70 (HSP70) and cytochrome P4501A(CYP1A) genes in liver and gills of non-targeted aquatic animal, Cyprinus carpio. Methods: Three different sublethal concentrations of IMI (T1=26.04 mg/L, T2= 20.38 mg/L, T3=17.36 mg/L) were selected and common carp fingerlings were exposed for 28 days where histological alterations and expression study of HSP70 and CYP1A in gills and liver of exposed fishes being studied on 7, 14, 21 and 28 days interval using standard procedure. Result: Marked histological alteration like hydropic degeneration and cellular infiltration ...

International Journal of Current Microbiology and Applied Sciences