Comparative efficiency of Geotrichum candidum microcapsules prepared with alginate alone and in combination with other polymers: In vivo evaluation

To investigate the usefulness of encapsulation technique in aquaculture feed, 11 weeks feeding experiment was designed to check in vivo comparative efficacy of G. candidum encapsulated with alginate (Alg) alone as well as in combination with starch (Alg-S) and xanthan (Alg-X) followed by coated with chitosan (Alg-C, Alg-S-C, Alg-X-C) and nano-chitosan (Alg-CN, Alg-S-CN, Alg-X-CN). Fingerlings of Labeo rohita (15.63 +/- 0.35 g) were evenly distributed in ten groups. The control group was fed without probiotics while one experimental group was provided un-encapsulated probiotic (G. candidum QAUGC-01 (1 x 10(9) CFU g(-1))), and other groups were given diet fortified with microcapsules of probiotic prepared with Alg, Alg-S, Alg-X, Alg-C, Alg-S-C, Alg-X-C, Alg-CN, Alg-S-CN and Alg-X-CN. Overall results indicated a significant effect of encapsulated probiotics supplemented diets on growth, feed conversion ratio, enzyme activities, hematology, immunological indices, lipid profile: total cholesterol, high- and low-density lipoprotein and triglyceride content of fish as compared to basal diet devoid of probiotic. Interestingly, chitosan-coated microcapsules of G. candidum supplemented diet groups showed comparatively improved performance as compared to fish fed diet supplemented with uncoated microcapsules. Furthermore, among chitosan-coated microcapsules, Alg-CN microcapsules of G. candidum showed the highest efficiency i.e., the most significant positive effect on all investigated parameters followed by Alg-C microcapsules of G. candidum. Current investigation reveals that the Alginate-nano chitosan encapsulating formulation is the best to improve the viability and target release of locally isolated G. candidum QAUGC-01 in the gastrointestinal tract of L. rohita. Hence, the current investigation suggests a possible way of improving the growth and health status of L. rohita by feeding a diet supplemented with Alg-CN microcapsules of G. candidum.