Introduction
Th e incidence of microbial diseases has increased
dramatically in accordance with the growth of
fi sh larvae production, and high mortalities occur
during the larval fi rst feeding due to the incidence of
pathogenic and opportunistic bacteria (1). Diff erent
authors have suggested that this infection happens
mainly through the food chain, and especially during
feeding with Artemia (2). Live feed sources such as
Artemia play an important role in the dietary regime
of fi sh and shellfi sh larvae produced in industrial
hatcheries because of their nutritional profi les (3).
However, live feed can be a source of pathogenic
bacteria, such as Vibrio, responsible for fi sh and
aquatic animal pathologies in hatchery environments.
For this reason, the prevention of disease spreading
through the feed animal is essential in aquaculture
(4-6). Products that can enhance host immunity
and disease resistance, such as immunostimulants
and probiotics, are being used in shrimp disease
prevention and have garnered much interest in
recent years (7). Probiotics are harmless bacteria that
promote the wellbeing of a host animal and contribute
to the direct and/or indirect protection of the host
animals against harmful bacteria. Th e positive eff ects
of applying certain benefi cial bacteria in aquaculture
have been well documented, and treatments with
probiotics have also rapidly increased. Several research
articles regarding the benefi ts of using Bacillus to
improve shrimp growth performance, survival,
immunity, and disease resistance in aquaculture have
been published (7,8). Vaseeharan and Ramasamy
(4) reported on the antagonistic eff ect of B. subtilis
BT23 against pathogenic vibrios in tiger shrimp
(Penaeus monodon), which showed a 90% reduction
in cumulative mortality. Other microbiological
studies have demonstrated that Bacillus sp. and
Aeromonas hydrophila can protect Artemia cultures
against pathogenic Vibrio (9-11). Th e addition of
Bacillus coagulans SC8168, as a water additive for
shrimp larvae, signifi cantly increases their survival
rate and some digestive enzyme activities (10). In
the search for more eff ective and environmentally
friendly treatments, these previous studies concluded
that it is necessary for other research activities to be
developed with the aim of fi nding other probionts
as biocontrol agents against pathogenic species in
shrimp larval cultures. Th e present study aimed to
fi nd a possible probiotic for Artemia cultures through
the investigation of the probiotic properties of 2
Bacillus strains, their eff ect on the Artemia culture,
and their role in the enhancement of Artemia larvae
resistance against pathogenic Vibrio.