• Sonia Patharia

The aquatic environment is affected by different types of bacteria, which cause many types of diseases. Aeromonas hydrophilla causes a disease known as Motile Aeromonas Septicemia [MAS], which affects aquatic environments. MAS is responsible for the mass mortality of aquaculture species. Our aim was to determine the histopathological changes in Cirrhinus mrigala (Indian major carp fish) following Aeromonas hydrophilla induction. Aeromonas hydrophila was detected, isolated and identified from infected fish obtained from Anasagar Lake situated in Ajmer, Rajasthan (India). Fish showed reddish scar near ventral surface, fin rot, pale body color, external haemorrhages. For the detection of A.hydrophila BactAlert 3D 60 System was used. Blood sample from diseased fish inoculated onto the BactAlert culture media. MacConkey agar and Ship blood agar used for isolation of A. hydrophila. Bacteria finally identified by their specific morphological and biochemical characteristics. Further characteristics of the isolate were conducted using the vitek 2 compect system. One Year old C. mrigal carps obtained from the Aquaculture Farm. After acclimatization 4 culture tanks containing 100 L aerated water were setup and divided in two groups (G1 and G2), G1 group for control and G2 group for experimental (infected with A. hydrophila). The study of histopathological changes in C. mrigala were observe for 20, 40 and 60 days. Fishes in group G2 were injected with A. hydrophila isolate which grown over night on MacConey agar at 37°C. Fishes of G2 group injected an intraperitoneally with 0.1ml concentration of 108 CFU/ml of A. hydrophila isolates. Control (G1 group) fishes injected with 0.1ml of saline. Experimental infected fishes showed clinical signs of weakness, septicemia, anorexia, hyperemia, and lysis of the fins. Fluid accumulation was visible in abdomen and swelling in internal organs.

Aeromonas hydrophilla, Blood agar, Cirrhinus mrigala, Histopathology, Intraperitoneally, MacConkey agar,

"Histopathological changes induced in Cirrhinus mrigala due to Aeromonas hydrophila ", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.12, Issue 11, page no.a606-a613, November-2025, Available :http://www.jetir.org/papers/JETIR2511072.pdf

"Histopathological changes induced in Cirrhinus mrigala due to Aeromonas hydrophila ", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.12, Issue 11, page no. ppa606-a613, November-2025, Available at : http://www.jetir.org/papers/JETIR2511072.pdf