Investigating the impact of external application of formalin and potassium permanganate on hematological, immunological, and biochemical profiles in Labeo rohita fingerlings

Abstract

The present study aimed to elucidate the suitability of formalin and KMnO₄ as therapeutics for fish diseases in Indian major carp, Labeo rohita, while considering their impact on fish stress levels. Acute toxicity tests revealed that the 96-hour LC₅₀ values for formalin and KMnO₄ were 66.58 ppm and 2.89 ppm, respectively. Sub-lethal concentrations of formalin (6.65 ppm, 3.32 ppm, and 2.21 ppm) and KMnO₄ (0.289 ppm, 0.145 ppm, and 0.096 ppm), along with control groups, were administered to the fish for different exposure periods (24, 48, 72, and 96 hours) and different hematological, biochemical, and immunological parameters were analyzed. The findings demonstrated that formalin exposure resulted in a significant decrease (p < 0.05) in hematological parameters, immunological parameters, and serum protein levels. Conversely, formalin exposure led to significant increases (p < 0.05) in serum glucose, SGOT, SGPT, and ALP levels. In contrast, KMnO₄ exposure significantly decreased (p < 0.05) hematological parameters and serum protein levels, while significantly increasing (p < 0.05) immunological parameters. To evaluate curative efficacy, challenge studies were conducted using three sub-lethal concentrations of formalin and KMnO₄ against Aeromonas hydrophila (ATCC 7966) infection. Based on the aforementioned results, the recommended doses of formalin and KMnO₄ were found to be 6.65 ppm and 0.289 ppm, respectively.

Keywords:

• Formalin
• potassium permanganate
• acute toxicity
• physiological response
• L. rohita
• Aeromonas hydrophila

Acknowledgements

All the authors would also like to express sincere gratefulness to Dr. Anupam Mishra, Vice-Chancellor, Central Agricultural University, Imphal for providing all kinds of essential facilities to conduct the present study.

Ethics statement

This study was reviewed and approved by the Institutional Animal Ethics Committee (IAEC) of College of Fisheries, Central Agricultural University, Imphal, India. All the live fish were handled humanely and efforts were made to minimize suffering and to reduce the number of fish used. The toxicity or the bioassay test was done as per the OECD guidelines for the testing of chemicals (Test No. 203, Fish Acute Toxicity Test) in a static system.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article.

Additional information

Funding

This work used the facilities that were funded by the National Fisheries Development Board, Hyderabad, India and Department of Fisheries, Ministry of Fisheries, Animal Husbandry and Dairying, Government of India under Pradhan Mantri Matsya Sampada Yojana (PMMSY) through the project ‘National Surveillance Programme for Aquatic Animal Diseases Phase I and Phase II, respectively’.