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20171
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Subject: Aquaculture × Author: RAVEENDRA, MATLAPUDI × End date: 2017 × Start date: 2017 × Thesis Type: M.F.Sc ×
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    ThesisItemOpen Access
    SCREENING FOR INCIDENCE OF MICROSPORIDIAN PARASITE Enterocytozoon hepatopenaei (EHP) IN Litopenaeus vannamei FROM AQUACULTURE PONDS IN SPSR NELLORE DISTRICT OF ANDHRA PRADESH
    (SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA, 2017-02) RAVEENDRA, MATLAPUDI; HARI BABU, P (MAJOR); Neeraja, T; MADHAVAN, N
    Hepatopancreatic Microsporidiosis (HPM) caused by Enterocytozoon hepatopenaei (EHP), a microsporidian parasite to be associated with slow (retarded or stunted) growth and white feces syndrome (WFS) in cultured shrimp in many of the shrimp growing countries in Asia, also in India. In the present study, shrimp samples from various shrimp ponds from different Mandals of SPSR Nellore district, Andhra Pradesh, India, were collected over a period of five months (February 2016 to June 2016). Important diagnosis observed were histopathological studies, molecular technique (PCR) and also the effect of this parasite on pond profitability. Histologically, the infected animals showed severe degeneration of hepaotopancreatic tubule, basophilic inclusions resembling the developmental stages of EHP were found in the epithelial cells and large number of spore aggregations was observed in the tubular lumen. Enlargement of haemal sinuses was also observed in some cases. The problems associated with slow growing shrimp populations were found to be basically two groups, these are; Group A: slow growing animals associated with white gut and white feces and Group B: slow growing animals without any clinical signs. Samples from these two groups (25 case studies each) were examined for the presence or absence of EHP. As per group A population, 12 samples were positive by histopathologically and another three more samples are further confirmed by PCR, the remaining 10 samples did not give any recognizable indication. In the group B animals, showed only the presence of EHP in 11 samples histopathologically and further confirmation with PCR tested positive in 5 more samples, the remaining 9 samples were not showing any apparent signs of infection. From this study, out of 50 pond case studies, 31 cases were showing EHP symptoms with 62 % prevalence. To evaluate the economical importance of this parasite on pond profitability, five farm pond production effected by both EHP and white feces syndrome were compared with 5 normally performed shrimp population with biosecured environment. EHP-infected ponds have poor performance in average daily growth (ADG), days of culture (DOC), average body weight (ABW), feed conversion ratio (FCR) and shrimp biomass compared to normal healthy ponds. The portal route of entry of pathogen into shrimp was evaluated by performing oral feed bioassay, it was revealed that EHP can be transmitted through per os feeding of EHP infected hepatopancreas tissue to healthy shrimp.