An experiment was conducted to explore the pathogenic effect of WSSV infection in reproduction of... more An experiment was conducted to explore the pathogenic effect of WSSV infection in reproduction of the Indian white shrimp, Fenneropenaeus indicus by investigating the time-course expression of female reproduction gene, namely vitellogenin (Vg) and thrombospondin (TSP), following WSSV challenge. Increased levels of expression for both Vg and TSP was observed in the infected group at 30 h post-infection followed by a decrease in the levels at 60 h post infection compared to the controls. The results indicate that both Vg and TSP might play a role in the immune functions of shrimp in addition to their well known roles in reproduction in penaeid shrimps.
The concept of “biofloc technology” is changing the facet of intensive aquaculture with scope to ... more The concept of “biofloc technology” is changing the facet of intensive aquaculture with scope to attain high productivity in a sustainable manner. In biofloc, dense heterotrophic bacterial community is developed through C:N ratio manipulation, where the system becomes bacterial dominated rather than algae dominated and takes care of the wastes generated through in situ bioremediation. Protein is utilised in two ways; as feed for the shrimp and as microbial floc when the heterotrophic microbes convert the nitrogenous wastes into protein. It also promises a healthy rearing system, which is increasingly identified as one possible solution for disease problems especially those striking at early stages. The purpose of this study was to evaluate the effect of biofloc and periphyton technology (BPT) on the growth and immunomodulatory performance of Pacific white shrimp Penaeus vannamei during nursery and grow-out culture. The experimental BPT treatments with three tier substrate system wit...
Biofloc technology (BFT) is a novel modern aquaculture farming technique used to reduce toxic nit... more Biofloc technology (BFT) is a novel modern aquaculture farming technique used to reduce toxic nitrogen concentration, act as in situ food source and eradicate pollutants using carbon and therefore to control C:N ratio in an aquaculture system. In this study, effect of different C:N ratios of a biofloc based system on water quality such as the level of Total ammonia nitrogen (TAN) nitrite-nitrogen (NO-N) and nitrate nitrogen (NO-N) were explored. Further, the growth and immunity status of shrimp L. vannamei under the influence of different C:N ratios were evaluated. Two of the C:N ratios (15 and 20) could significantly (P < 0.05) reduce TAN, NO-N and NO-N levels (0.456 ± 0.01, 0.145 ± 0.09, and 0.102 ± 0.02 ppm) compared to control (1.45 ± 0.1, 0.749 ± 0.14 and 0.675 ± 0.16 ppm). Large variations in the frequency distribution of operational taxonomic units (OTUs) for the bacterial community in water with different C:N ration (BFT) and control were observed. Vibrios often considere...
is a major pathogen of shrimp, causing economic loss to the aquaculture industry. For the first t... more is a major pathogen of shrimp, causing economic loss to the aquaculture industry. For the first time, a completegenome of an Indian isolate of this virus has been deciphered using Illumina and Nanopore sequencing technologies. The genome has 280,591 bp with 442 predicted coding genes.
The moribund shrimps were exhibiting yellow discoloration of the cephalothorax, blackening of gil... more The moribund shrimps were exhibiting yellow discoloration of the cephalothorax, blackening of gills and ulcers in the uropod and telson region. PCR for OIE listed viral pathogens ruled out known viral infections. No bacteria was present in haemolymph however, low level of Vibrios i.e. Vibrio harveyi, V. parahaemolyticus and V. alginolyticus was found both in the water collected from the broodstock tanks and affected tissue region. Histopathological examination of affected tissues revealed presence of highly invasive fungal hyphae both by routine and specific fungal stain. PCR amplification of the ITS region (approximately 900 bp) and sequencing confirmed presence of Pythium insidiosum . Phylogenetic analysis of this isolate placed it among the environmental isolates.
Abstract Vibrio parahaemolyticus is an important shrimp & human pathogen and a special strain... more Abstract Vibrio parahaemolyticus is an important shrimp & human pathogen and a special strain of it harbouring toxic plasmid can cause Acute Hepatopanreatic Necrosis Disease (AHPND) to shrimp. An attempt was made to isolate and further characterize this bacterium from shrimp farms of south east coast of India. From 381 shrimp farms sampled over a period of four years, 105 isolates were presumptively identified as V. parahaemolyticus. All the 105 isolates were found to be negative for PirA and PirB toxin, characteristic of AHPND V.parahaemolytiucs. The challenge experiments with representative isolates required higher number of bacteria to cause shrimp mortality. The isolates were negative for thermostable direct haemolysin (tdh), tdh related haemolysin (trh) and type III secretion system alpha and beta. The isolates were tested to be sensitive to majority of the antibiotics. This study thus indicates that V. parahaemolyticus isolates recovered from aquaculture ponds of Southeast coast of India are non-shrimp pathogenic and non-human pathogenic. Direct tissue samples (hepatopancreas and stomach) and Tryptic Soy Broth enriched bacteria population from these tissues were also found to be negative for PirA and PirB toxin, characteristic of AHPND. Based on this evidence, AHPND was not detected in any of the samples collected from these shrimp culturing areas.
Motile aeromonads are a heterogeneous group of organisms which are involved in a number of diseas... more Motile aeromonads are a heterogeneous group of organisms which are involved in a number of disease syndromes of warm water fish. They are commonly associated with bacterial haemorrhagic septicaemia, infectious dropsy, red mouth disease, ulcerative conditions etc. A variety of factors has been considered to be associated with virulence including haemolysins, proteases, surface array protein, acetylcholinesterase etc. We have studied the immune response of Indian major carps to antigens of motile aeromonads. The Indian major carp, Labeo rohita, showed immunological memory and secondary response on booster administration. The extent of protection showed good correlation with titres of agglutinating antibody. When polyvalent vaccine was used, the fish showed antibody titres against all the component strains. However, the level of antibody was less compared to immunization by monovalent vaccines. Cross-reacting antibodies induced by monovalent vaccines showed varying degrees of protection.
An experiment was conducted to explore the pathogenic effect of WSSV infection in reproduction of... more An experiment was conducted to explore the pathogenic effect of WSSV infection in reproduction of the Indian white shrimp, Fenneropenaeus indicus by investigating the time-course expression of female reproduction gene, namely vitellogenin (Vg) and thrombospondin (TSP), following WSSV challenge. Increased levels of expression for both Vg and TSP was observed in the infected group at 30 h post-infection followed by a decrease in the levels at 60 h post infection compared to the controls. The results indicate that both Vg and TSP might play a role in the immune functions of shrimp in addition to their well known roles in reproduction in penaeid shrimps.
The concept of “biofloc technology” is changing the facet of intensive aquaculture with scope to ... more The concept of “biofloc technology” is changing the facet of intensive aquaculture with scope to attain high productivity in a sustainable manner. In biofloc, dense heterotrophic bacterial community is developed through C:N ratio manipulation, where the system becomes bacterial dominated rather than algae dominated and takes care of the wastes generated through in situ bioremediation. Protein is utilised in two ways; as feed for the shrimp and as microbial floc when the heterotrophic microbes convert the nitrogenous wastes into protein. It also promises a healthy rearing system, which is increasingly identified as one possible solution for disease problems especially those striking at early stages. The purpose of this study was to evaluate the effect of biofloc and periphyton technology (BPT) on the growth and immunomodulatory performance of Pacific white shrimp Penaeus vannamei during nursery and grow-out culture. The experimental BPT treatments with three tier substrate system wit...
Biofloc technology (BFT) is a novel modern aquaculture farming technique used to reduce toxic nit... more Biofloc technology (BFT) is a novel modern aquaculture farming technique used to reduce toxic nitrogen concentration, act as in situ food source and eradicate pollutants using carbon and therefore to control C:N ratio in an aquaculture system. In this study, effect of different C:N ratios of a biofloc based system on water quality such as the level of Total ammonia nitrogen (TAN) nitrite-nitrogen (NO-N) and nitrate nitrogen (NO-N) were explored. Further, the growth and immunity status of shrimp L. vannamei under the influence of different C:N ratios were evaluated. Two of the C:N ratios (15 and 20) could significantly (P < 0.05) reduce TAN, NO-N and NO-N levels (0.456 ± 0.01, 0.145 ± 0.09, and 0.102 ± 0.02 ppm) compared to control (1.45 ± 0.1, 0.749 ± 0.14 and 0.675 ± 0.16 ppm). Large variations in the frequency distribution of operational taxonomic units (OTUs) for the bacterial community in water with different C:N ration (BFT) and control were observed. Vibrios often considere...
is a major pathogen of shrimp, causing economic loss to the aquaculture industry. For the first t... more is a major pathogen of shrimp, causing economic loss to the aquaculture industry. For the first time, a completegenome of an Indian isolate of this virus has been deciphered using Illumina and Nanopore sequencing technologies. The genome has 280,591 bp with 442 predicted coding genes.
The moribund shrimps were exhibiting yellow discoloration of the cephalothorax, blackening of gil... more The moribund shrimps were exhibiting yellow discoloration of the cephalothorax, blackening of gills and ulcers in the uropod and telson region. PCR for OIE listed viral pathogens ruled out known viral infections. No bacteria was present in haemolymph however, low level of Vibrios i.e. Vibrio harveyi, V. parahaemolyticus and V. alginolyticus was found both in the water collected from the broodstock tanks and affected tissue region. Histopathological examination of affected tissues revealed presence of highly invasive fungal hyphae both by routine and specific fungal stain. PCR amplification of the ITS region (approximately 900 bp) and sequencing confirmed presence of Pythium insidiosum . Phylogenetic analysis of this isolate placed it among the environmental isolates.
Abstract Vibrio parahaemolyticus is an important shrimp & human pathogen and a special strain... more Abstract Vibrio parahaemolyticus is an important shrimp & human pathogen and a special strain of it harbouring toxic plasmid can cause Acute Hepatopanreatic Necrosis Disease (AHPND) to shrimp. An attempt was made to isolate and further characterize this bacterium from shrimp farms of south east coast of India. From 381 shrimp farms sampled over a period of four years, 105 isolates were presumptively identified as V. parahaemolyticus. All the 105 isolates were found to be negative for PirA and PirB toxin, characteristic of AHPND V.parahaemolytiucs. The challenge experiments with representative isolates required higher number of bacteria to cause shrimp mortality. The isolates were negative for thermostable direct haemolysin (tdh), tdh related haemolysin (trh) and type III secretion system alpha and beta. The isolates were tested to be sensitive to majority of the antibiotics. This study thus indicates that V. parahaemolyticus isolates recovered from aquaculture ponds of Southeast coast of India are non-shrimp pathogenic and non-human pathogenic. Direct tissue samples (hepatopancreas and stomach) and Tryptic Soy Broth enriched bacteria population from these tissues were also found to be negative for PirA and PirB toxin, characteristic of AHPND. Based on this evidence, AHPND was not detected in any of the samples collected from these shrimp culturing areas.
Motile aeromonads are a heterogeneous group of organisms which are involved in a number of diseas... more Motile aeromonads are a heterogeneous group of organisms which are involved in a number of disease syndromes of warm water fish. They are commonly associated with bacterial haemorrhagic septicaemia, infectious dropsy, red mouth disease, ulcerative conditions etc. A variety of factors has been considered to be associated with virulence including haemolysins, proteases, surface array protein, acetylcholinesterase etc. We have studied the immune response of Indian major carps to antigens of motile aeromonads. The Indian major carp, Labeo rohita, showed immunological memory and secondary response on booster administration. The extent of protection showed good correlation with titres of agglutinating antibody. When polyvalent vaccine was used, the fish showed antibody titres against all the component strains. However, the level of antibody was less compared to immunization by monovalent vaccines. Cross-reacting antibodies induced by monovalent vaccines showed varying degrees of protection.
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