Evaluation of commercial application of dietary encapsulated probiotic (Geotrichum candidum QAUGC01): Effect on growth and immunological indices of rohu (Labeo rohita, Hamilton 1822) in semi-intensive culture system.

Encapsulated probiotic administration can be a nutritional strategy to improve the growth performance and immune status of fish. Here commercial application of encapsulated G. candidum was evaluated as a feed supplement to fingerlings of L. rohita reared in earthen ponds under semi-intensive culture conditions. Fingerlings with an average body weight of 20 ± 2.34 g were distributed randomly in three groups and experiment was conducted in triplicate. The control group (P0) was fed 35% protein basal diet while the two treated groups, P1 and P2 were fed basal diet supplemented with 109 CFU g-1 un-encapsulated (free) and encapsulated G. candidum, respectively, for eleven weeks. Results indicated significantly (P < 0.05) improved growth rate, intestinal enzyme activities (protease, amylase and cellulase) and hemato-immunological indices (RBCs, Hb, HCT, WBCs, MCHC, respiratory bursts and phagocytic activity, total protein, lysozyme, IgM), upregulation of heat shock protein HSP 70 gene in muscle, intestine and liver tissues and reduction of serum AST and ALT activities, total cholesterol and triglyceride in fish fed G. candidum supplemented diets (P1 and P2 groups) as compared to basal diet (P0 group). However, diet supplemented with encapsulated G. candidum showed the most significant (p < 0.001) positive effect in comparison to un-encapsulated probiotic. In conclusion, a pronounced effect of G. candidum especially in the encapsulated form on the growth, health status and immunity of L. rohita reared in semi intensive culture system, suggesting its application as a feed additive in practical/commercial semi-intensive earthen pond culture system.