PSEUDOMONAS SEPTICEMIA IN LABEO ROHITA (HAM.) AND CYPRINUS CARPIO (LINN.) IN ANDHRA PRADESH–NATURAL OCCURRENCE AND ARTIFICIAL CHALLENGE

摘要

Objective: The aim of present work is to identify pathogens of diseased Labeo rohita and Cyprinus carpio and to check their pathogenicity. Materials and Methods: Incidences of Pseudomonas septicemia were recorded in the months of October to December, 2011 and January and February, 2012 in Labeo rohita and Cyprinus carpio. A total of 2,076 fishes were screened only affected fishes were brought to the laboratory in living condition. Diseased fish samples were collected randomly every week at regular interval from local fish farms and fish markets, Bhimavaram, Andhra Pradesh, India. Standard microbiological methods were used for isolation and characterization of bacteria associated with diseased fishes. Results: The clinical symptoms of affected fishes includes erosions at the bases of fins, hemorrhages and skin lesions on the surface of the body, loosening of scales, mucous secretion and in advance stages in some fishes shallow to deep ulcers were observed. Bacteriological examination of infected fishes showed that the occurrence of four species of Pseudomonads namely Pseudomonas anguilliseptica, P. fluorescens, P. aeruginosa, and Pseudomonas sp. Among four species P. anguilliseptica and P .fluorescens were consistently obtained from external lesions and hemorrhages and internal organs like liver, kidney, spleen and gills of diseased fishes. Artificial challenge studies indicated that P. anguilliseptica and P. fluorescens were highly pathogenic to both species of fishes. While P .aeruginosa and Pseudomonas sp. were fails to fulfil the Koch postulate. The obtained LD50 values of P. anguilliseptica for L. rohita and C. carpio were 2×104.64CFU ml-1and 2×104.75CFU ml-1, respectively while in case of P. fluorescens the LD50values for L. rohita and Cyprinus carpio was 104.5and 104.86CFU ml-1, respectively. Conclusion: P. anguilliseptica and P. fluorescens were pathogenic fishes