Comparative Efficiency of Two Indigenously Isolated Probiotic Strains on Growth Performance and Health Profile of Advance Fry of Labeo rohita

Due to variations in the mode of action and efficacy, the “one‐size‐fits‐all” model cannot be applied to probiotics. Thus, selecting specific probiotic strains/species for the selected fish species in a particular culture condition/environment is a prerequisite to acquire maximal benefits. Local strains of bacteria Bacillus cereus and yeast Geotrichum candidum‐ QAUGC‐01 were investigated as potential probiotics for Labeo rohita . An eleven‐week feeding trial was conducted in triplicate using four experimental groups: control A (basal feed only), T 1 (basal feed supplemented with G. candidum at 1 × 10 9 CFU/g feed), T 2 (basal feed supplemented with B. cereus at 1 × 10 9 CFU/g feed), and T 3 (basal feed supplemented with both probiotics at 1 × 10 9 CFU/g feed). The effects of probiotic supplementation were assessed through survival, growth performance, gut microbiota, enzyme activity, muscle composition, haematological and immunological responses, and serum aspartate aminotransferase (AST) activity. The results indicated the most significant effect ( p < 0.001) of G. candidum in terms of final weight, specific growth rate, biomass, survival (%), gut microbial count, and muscle composition in T1 A group along with the highest activity of all studied intestinal enzymes. Moreover, a significant increase ( p < 0.05) in erythrocytes (RBCs), leukocytes (WBCs), haemoglobin (Hb), and haematocrit (HCT %) was observed in the T1 A group, followed by the T3 A group. The immunological indices such as plasma protein level, immunoglobulin (IgM), serum lysozyme activity, respiratory burst, and phagocytic activity also showed a similar trend, that is, highest in T1 A followed by T3 A, and the lowest values were observed in the T2 A group. AST level showed an opposite trend as it was the highest in the T2 A group, while the lowest level was observed in the T1 A group. Furthermore, after performing a challenge test with Aeromonas hydrophila , enhanced survival ( p < 0.001) was found in the T1 A group. This investigation reveals the higher efficiency of G. candidum as compared to B. cereus and suggests its application for improving L. rohita advanced fry production.