Eisay Ali K.A. , Sriteja G. , Sunita K.

Department of Zoology & Aquaculture, Acharya Nagarjuna University, Nagarjuna Nagar 522510, Guntur, Andhra Pradesh, India
Author    Correspondence author
International Journal of Aquaculture, 2026, Vol. 16, No. 4   
Received: 26 Jun., 2026    Accepted: 11 Aug., 2026    Published: 20 Aug., 2026

This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Aquaculture is a rapidly expanding sector that contributes significantly to global food production by cultivating aquatic organisms under controlled conditions. However, a major obstacle to aquaculture is the widespread use of antibiotics since the emergence of antibiotic-resistant bacteria. Thus, the immunostimulants are replacing chemotherapeutic therapies for aquaculture disease control. In such a scenario, morphometric and haematological evaluations are necessary to check the impact of immunostimulants on the health of both healthy and pathogen-infected fish. Because of its high nutritional value and other beneficial effects on human health, Catla catla has been a popular cultured freshwater fish in India, limited information is available regarding the effects of dietary immunostimulants on Aeromonas hydrophila-challenged C. catla. Therefore, the study examined the effects of immunostimulants on C. catla morphometric and haematological parameters under normal and Aeromonas-infected conditions. This study found that oral administration of immunostimulants such as vitamin C, vitamin E, chitin, chitosan, and levamisole significantly increased body weight, feed intake, feed conversion, and biomass. Morphometric investigations demonstrated that immunostimulant-supplemented feed considerably affected body length, width, and weight. Among all the tested feeds, vitamin C showed the strongest growth-promoting effect under Aeromonas hydrophila infection. The haematological analysis demonstrated that immunostimulants substantially increased haemoglobin content, RBC, WBC, neutrophil, lymphocyte, monocyte counts, and ESR as well as decreased eosinophil count and do not exhibit any effect on basophil count. Among all the immunostimulants Vitamin E has shown more effect in improving the haematological parameters. In conclusion, immunostimulants promote C. catla growth, immunity, and survival under Aeromonas infection. Thus, among the above selected immunostimulants, Vitamin C and Vitamin E are more potent and can be used in developing alternative dietary strategies for improving fish health management and reducing dependence on antibiotics in aquaculture.

Aeromonas hydrophila; Catla catla; Haematology; Immunostimulants; Morphometry