Studies On White Faecal Syndrome In Litopenaeus. vannamei (Boone, 1931)
Academic Leadership - Online Journal,
Vol. 21 No. 6 (2020): Vol-21-Issue-6-June-2020
The white faecal syndrome (WFS) of Litopenaeus vannamei has been carried out during the period of 2018 to 2019 in Vellar estuary aqua-farms, Parangipettai, South East coast of India.. The results of present study revealed that, WFS was observed in 43 days of culture on wards to up to 65 days of culture, thereafter no white faecal syndrome. The symptoms of WFS in-infected animals showed hepatopancreas and gut become white and pale yellow in colour, the infected gut in bulging and elastic nature. The performance of WFS infected ponds were showed poor growth (ADG 0.1 to 0.2g), and survival (45%) and increase in FCR (1:3.1). The incidence of WFS was high in low alkalinity (45-70ppm) and also present study showed the fresh water ponds less in WFS than the sea water ponds. The microbial load of Vibrio in WFS infected ponds was higher than the normal sea water and fresh water ponds. A total of 485 green and yellow colonies were isolated from TCBS agar plates. Significantly 368 colonies were identified such as Vibrio paraheamolyticus, V. vulnificus, V. mimicus, V. damsel, V. anguillarum, V. cholera, V. harveyi, V. splendidus, V. fluvialis and V. alginolyticus. Among these, the maximum percentage (40.48) in V. parahaemolyticus and minimum (2.44) in V. damsel. The histopathological investigation revealed that the hepatopancreas is smaller in size , atrophied tubular cells and absence of storage vacuoles. The gut, loss of gut fiber structure, expansion of the sarcomeric space, degeneration of basement membrane and inner lining of epithelial cells filled with gut cavity and damaged gill filament and darkening due to secondary infection of WFS infected animals.
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