Abstract:
Probiotics are living microorganisms that confer positive effects on the health of the
digestive system when incorporated with feed in a defined dosage and help to
stimulate the immune response in fish against virulent fish bacterial pathogens.
Therefore, focusing on the gastrointestinal health of fish is quintessential. This study
was carried out to evaluate the effect of probiotic isolated from the intestine of healthy
Nile tilapia (Oreochromis niloticus) on the growth performance and survival of Nile
tilapia. A total of 180 healthy juvenile Nile tilapia (5.61±0.14g, 4.09±0.24cm) were
randomly divided into five experimental variants. Five experimental diets were
supplemented with different concentrations of Lactobacillus namely, Control diet (no
probiotic, d0), High dose gut Lactobacillus (1.5×109 CFU/g, d1), Medium dose gut
Lactobacillus (1.5×108CFU/g, d2), Low dose gut Lactobacillus (1.5×107CFU/g, d3),
and Yoghurt Lactobacillus (1.5×108 CFU/g, d4). Fish were fed 3% of their body
weight for 8 weeks and subjected to a 5 days Aeromonas hydrophylla challenge test.
Results showed that the fish fed with diet d1 had the best growth performance. Weight
gain, length gain and specific growth rate were significantly higher in fish fed with
d1 (p < 0.05), while feed conversion ratio was not significantly different (p>0.05)
among the experimental groups. The challenge test result revealed that fish fed with
d1 had a high survival rate against Aeromonas hydrophylla than other treatments.
Therefore, it is concluded that using fish gut probiotic as supplementary feed on
Oreochromis niloticus showed positive effects on growth parameters and health
status. Furthermore, this study indicates the feasibility of using isolated probiotics as
a feed additive and as an immune enhancer in aquaculture.
