Application of micro-encapsulated probiotic Bacillus NP5 and prebiotic mannan oligosaccharide (MoS) to prevent streptococcosis on tilapia Oreochromis niloticus

Abstract

Streptococcus agalactiae is one of the fish pathogen which can cause mortality up to 90% in commercial tilapia farms. This study aimed to evaluate the effectiveness of supplementation of micro-encapsulated probiotic (Bacillus NP5), prebiotic (MOS) and combination of those materials (synbiotic) through the feed on growth performances and immune responses of tilapia infected with S. agalactiae. The probiotic cells were encapsulated by spray drying method. The experimental fish were reared for 40 days and fed with feed-supplemented with probiotic, prebiotic and synbiotic and without any supplementation to the feed (positive and negative control). On day 40, all fish except negative control were challenged by S. agalactiae via intraperitoneal route injection in amount of 0.1 mL (106 CFU mL-1). This study showed that administration of 0.4% prebiotic to the feed resulted the best growth performance in the end of feeding trial and survival rate after the challenge test with S. agalactiae.