Journal of Environmental Biology

Effect of Pseudomonas aeruginosa on the giant freshwater prawn, Macrobrachium rosenbergii - histopathological and electron microscopic study

K. Ramalingam*¹ and S. Ramarani²

¹PG (Aquaculture) and Research Department of Advanced Zoology and Biotechnology,

Government Arts College, Nandanam, Chennai-600 035, India

²Chellamal College for Women, Guindy, Chennai-600 035, India

(Received: August 04, 2005 ; Revised received: February 10, 2006 ; Accepted: March 29, 2006)

Abstract: The giant freshwater prawn Macrobrachium rosenbergii was injected with an inoculum containing LD₅₀ 96 hr dose of 10⁷ Pseudomonas aeruginosa (MTCC  1688) to determine the histopathological effects in vivo. The comparison of tissues of both the control and the bacterial endotoxin treated prawns after 96 hr revealed significant degenerative changes in treated prawns. Both light microscopic and electron microscopic observations revealed the infiltration of  the tissues of Pseudomonas sp in the muscular and hepatopancreatic tissues of prawn. The muscular tissue changes in the myofibrillar arrangement with blockage at the gap junctions and necrotic lesions were observed. The hepatopancreatic cells were vacuolated with hypertrophied nucleus. Atrophy of hepatopancreatic tubules was conspicuous. The pathogenicity of Pseudomonas aeruginosa is attributed to its infiltration and multiplication inside the tissues and the consequent release of extra-cellular enzymes for its metabolism. The degeneration of host tissues is also attributed to the latter.

Key words:   Macrobrachium rosenbergii, Pseudomonas aeruginosa, Extracellular proteases, Endotoxin

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