Evaluation of microencapsulated Lactobacillus bulgaricus on growth indices and some blood factors of Nile tilapia Oreochromis niloticus

Abstract

Introduction: Tilapia is one of the most important farmed fish in the world and has been
suggested as a source of protein for developing countries. Micro encapsulation of probiotics
using natural biodegradable polymers and their oral administration, not only protect
probiotics from degradation in the gastrointestinal tract, but leads to increased
bioavailability of immunogenic antigens due to controlled release of bacteria.
Materials & Methods: In the present study, Lactobacillus bulgaricus bacteria isolated
from the gastrointestinal tract of native fish of Khuzestan province were used for micro
coating with alginate / chitosan and oral administration for 60 days. During the study period,
some growth and blood factors were measured. One hundred and sixty Nile tilapia
(weighing 25±2 g) randomly divided in four groups in triplicates (40 pieces/treatment and
3 repetitions). Groups 1 and 2 were fed with food supplemented with encapsulated and
non-capsulated probiotic respectively. Group 3 was fed with alginate/chitosan free probiotic
and group 4 was fed with basal diet without supplementation. Experimental diet was
administrated for 60 days and fish biometry and blood sampling were conducted on days
zero, 30 and 60 of experiment.
Result: The results showed that most of the growth indices including: fish weight gain, feed
conversion ratio, feed efficiency ratio, specific growth rate and protein efficiency in the
group fed with microencapsulation bacteria were significantly improved compared to other
groups (p<0.05).
Conclusion: Blood factors were not affected by probiotic administration and probiotic
microencapsulation. Alginate / chitosan microparticles (108 cfu/g food) caused a significant
improvement in growth indices compared to probiotic treatment without micro coating.
However, fish blood factors were not affected by probiotic administration and probiotic
microencapsulation.