Ameliorative role of dietary acidifier potassium formate on growth metrics, blood chemistry, gut health and well-being indices of rohu, Labeo rohita fingerlings

Organic acids and their derivatives have been attributed to growth and well-being improvement in fish when supplemented in their diets. Therefore, this study was conducted to evaluate the ameliorative role of potassium formate (PF) in rohu Labeo rohita fingerlings. A total of 240 healthy rohu fingerlings (9.0 ± 0.5 g ± SE) were randomly divided into four equal groups in triplicates. Fish were fed with isonitrogenous feeds: PF10 (10 g PF/kg), PF20 (20 g PF/kg) and PF30 (30 g PF/kg). Feed without PF supplementation served as control. The results indicated that the specific growth rate (SGR) and feed conversion ratio (FCR) were significantly ( p <0.05) higher in PF10. Total serum globulin content was found significantly ( p <0.05) elevated in PF10 after the bacterial challenge. Non-specific lysozyme activity was significantly higher ( p <0.05) after the challenge. The digestive protease enzyme activity was significantly ( p <0.05) improved in PF10 treatment. Additionally, the digestive morphology of the treated fish was seen to be improved. Greater villus area, increased villus number, reduced lumen space in the hindgut, reduced vacuolation in mucosal folds and proliferation of goblet cells-like changes were observed in the PF-supplemented fish. Significantly ( p <0.05), a higher relative percentage of survival (RPS) was observed in PF10 and PF20 treatments. The study revealed that the dietary supplementation of rohu fingerlings with lower levels of potassium formate could enhance the nutritional efficiency and physiological activities of rohu fingerlings. This study serves as a baseline for future research on the application of formic acid derivatives and other acidifiers in carp culture.