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Author: ANUSHA, BOKKA × Start date: 2000 ×
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    ThesisItemOpen Access
    PATHOGENICITY OF Enterocytozoon hepatopenaei (EHP) AND ASSOCIATED WHITE FECES SYNDROME (WFS) IN FARM RAISED Litopenaeus vannamei PONDS OF ANDHRA PRADESH
    (SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA, 2018-11) ANUSHA, BOKKA; Haribabu, P (MAJOR); Neeraja, T; Madhavi, K
    Microsporidian parasite Enterocytozoon hepatopenaei (EHP) is an emerging pathogen of cultured penaeid shrimp causing hepatopancreatic microsporidiosis (HPM). This parasite causes slow growth in cultured shrimp Litopenaeus vannamei in many of the shrimp growing countries globally. In addition to this, from 2016 onwards a new disease called white feces syndrome (WFS) has been negatively impacting the shrimp farming industry. In the present study, shrimp samples from various L. vannamei ponds from different mandals of SPSR Nellore district, Andhra Pradesh, India collected over a period of five months from February to June, 2018. During the study period, the growth, survival and economic analysis of L. vannamei production was observed between EHP and WFS affected and unaffected ponds. Further, the prevalence of EHP and WFS was studied besides predisposing factors for EHP and WFS in L. vannamei. Nellore district was chosen as the study area in view of abundant L.vannamei shrimp farming activities in the district. The net weight gain (g) for normal ponds was ranging from 25.00-33.33g, for WFS infected ponds was ranging from 14.28-20.00 g followed by EHP infected ponds showed range from 6.66- 12.50 g. The survival rate was maximum at 37/m2 for normal ponds and minimum at 116/m2 for white feces infected ponds. In this study, the economic analysis of the shrimp farming practices was carried out for one crop with a culture period of 2 to 4 months or 60-120 days. In the present study, normal ponds recorded the gross sales of shrimp ranging from ₹8-14 lakh with the production cost per kg was Rs 230-390. Similarly, for white feces infected ponds, gross sale value of shrimp ranging from ₹5-18 lakh with average production cost per kg was Rs 165-350. And for EHP infected ponds gross sale returns was ranged from ₹84,000 to 8 lakh with production cost per kg was 120-230 rupees respectively. Important diagnosis were histopathological studies and by PCR. Histological observations of infected shrimps showed the degeneration of hepatopancreatic tubules, haemocytic infiltration, basophilic inclusions, melanised granuloma and large number of spore aggregations in the tubule lumen. From this study, out of 57 pond case studies, 41 cases showed EHP in WFS ponds with 80% prevalence and for WFS ponds showed 89% prevalence. In this study, the highest prevalence for white feces syndrome was observed in Muthukur mandal compared to the other mandals due to high stocking densities. The predisposing factors for EHP and white feces syndrome was Low quality seed, Vibrio bacterial infection and / or EHP infection might be responsible for white feces syndrome, High stocking densities, Over feeding or improper feed management, Contamination of white feces from infected ponds to healthy ponds, High water temperatures, Lack of proper Biosecurity measures, Poor/No pond preparation prior to stock PL’s are some of the factors associated with.