Shrimp culture is the most lucrative aquaculture sector in Asia-Pacific region. Recently, shrimp farms in India have been affected by the microsporidian parasite, Enterocytozoon hepatopenaei (EHP) associated with retarded growth without other clinical signs, causing significant economic losses to the shrimp industry. The present study was carried out to investigate the incidence of EHP in Penaeus vannamei farms of Nellore district of Andhra Pradesh, and to identify the carriers of EHP and the role of management in reducing the incidence of EHP in ponds. PCR analysis by two sets of EHP specific primers indicated the incidence of EHP to be 92.50%. Histopathological studies of the hepatopancreas of affected shrimp showed sloughing of the epithelial cells of hepatopancreatic tubules, lifting and detachment of epithelial layers of hepatopancreatic tubules and heavy damage of hepatopancreas. PCR screening of aquatic macro fauna in the farms showed that samples of crabs, polychaetesand non-penaeids were positive for EHP, implying that they could act as carriers of EHP. On the other hand, fishes were found negative. Strict implementation of Best Management Practices (BMPs) in one selected farm which was confirmed to be infected by EHP clearly showed that practice of BMPs and avoidance of carriers can definitely reduce the incidence of EHP during the subsequent culture in shrimp farms. After implementation of BMPs, significant improvement in growth rate, and Feed Conversion Ratio (FCR) were also observed. In the control pond where BMPs were not implemented, EHP continued to be present, affecting growth and FCR adversely. This is the first report comparing the role of management in EHP infection and identifying carriers of EHP in P. vannamei culture in India.
K e y w o r d sEnterocytozoon hepatopenaei,
Microorganisms had a pivotalrole in the aquatic environment by involving ecosystem productivity with relevant to the food chain from the primary producers to and flag end consumers to decompose the detritus. And also plays an important roleconcerning nutrient cycling, the nutrition of the cultured animals, oxygen production, digestion, water quality, disease control with the introduction of live useful microorganisms, and reduce the environmental impact of the effluent by natural mechanisms through Biofilters, Biofilms and Bioremediation process. The present review elevates the importance of microbes how they were champions in recycling, food web formation and how improves the healthy aquatic ecosystem.
The knowledge of sediment texture is important in the studies of distribution of living and non-living resources, identification of source of sediments, sediment patterns and nutrients. It is known that the macro-benthos in the aquatic environment are influenced by the texture of the sediment in which they establish themselves and live. Sediment quality guidelines are important tool for assessment of contamination in marine and estuarine sediments with biological significance of intertidal beaches. The grain size characteristics of sediments from aggrading and receding in beaches have been analyzed by several investigators, only very limited research has been done on the relationship between the intertidal faunal abundance, distribution and the sediment grain size distributions from eroding and accreting beaches of Mangaluru. Sediment variations mainly affect the species distribution, pattern of diversity, breeding, survival and other activities. The present study was carried out to determine the grain size distribution and species abundance in coastal Waters of Someshwara, Panambur and Bengre beaches along the Mangaluru, south west coast of India. The sampling of coastal water and sediment was carried out from August 2016 to July 2017 along the Mangaluru coast was studied. Spatial and temporal variations of the grain size distribution like granules, coarse sand, fine sand, and very fine sand textural components like sand, silt, clay and organic carbon percentages analyzed and correlated with intertidal species distribution, abundance in the selected stations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.