Effect of rearing systems and dietary probiotic supplementation on the growth and gut microbiota of Nile tilapia (Oreochromis niloticus) larvae

The establishment of the early-life gut microbiota plays an important role in fish development and influences host's health status growth performance. Different rearing conditions can impact initial colonization microbiota, while addition probiotics may also affect such colonization. However, how this larvae survival remains largely unexplored. In study, 3-day old Nile tilapia embryos were hatched until 9 days post fertilization (dpf) three systems, including one flow-through system (FTS) two identical recirculating aquaculture systems (RAS). When feeding started at 10 dpf, FTS RAS fed with a control diet, second diet coated B. subtilis spores (RASB). trial lasted 26 days, from to fry stage, during which survival, performance analyzed. reared showed significantly lower than those RASB, no differences observed apparent feed conversion ratio between treatments. resulted different compositions, strongly correlated rate standard body length harvest. Cetobacterium was enriched barely detected FTS-reared fry. Probiotic supplementation increased relative abundance beneficial Bacillus gut. Our findings indicate that supports better compared FTS, dietary probiotic further modulates bacterial composition stimulates presence bacteria early life.