Potential probiotic and health fostering effect of host gut-derived Enterococcus faecalis on freshwater prawn, Macrobrachium rosenbergii.
Category:- Journal; Year:- 2021
Discipline:- Fisheries & Marine Resource Technology Discipline
School:- Life Science School
Abstract
The present study investigated the potential probiotic
effect of Enterococcus faecalis against a pathogenic microorganism, Vibrio
harveyi occurring in the giant freshwater prawn (Macrobrachium rosenbergii). V.
harveyi was isolated from the intestine of M. rosenbergii through biochemical
tests and PCR-based molecular assays. An in-vitro challenge was conducted by
mixing isolated probiotic (5.12 log CFU/g) and V. harveyi (3.09 log CFU/g).
Feeds incorporated with E. faecalis (9.02 log CFU/g) were applied to the
treatment group during in vivo test in the aquarium and earthen pond (70 m2, 1
m depth). Pathogenic bacteria were found to be reduced after 8 h (from 5.02 to
3.62 log CFU/g) and 60 days (from 5.44 to 2.15 log CFU/g) of probiotic
administration in the in vitro and in vivo test, respectively. The E. faecalis
mixed feed also showed higher weight gain (WG%, 481.22% ± 17.71%; SGR%, 2.93% ±
0.18%) and digestive enzymes activities (amylase, 1.26 ± 0.08 unit/mg;
protease, 2.78 ± 0.02 unit/mg) compared to control group (WG%, 371.31% ±
13.35%; SGR%, 2.30% ± 0.32%; amylase, 0.7 ± 0.03 unit/mg; protease, 1.82 ± 0.02
unit/mg). Furthermore, the probiotic also improved the immune response by
augmenting NGH (from 73.33% ± 0.23% to 74.63% ± 0.11%) and SGH (from 22.24% ±
0.06% to 23.13% ± 0.08%) in the treatment group. Therefore, E. faecalis could
be recommended to use against bacterial infections of the M. rosenbergii.