The cultivation of microbial species remains a primary challenge
in microbiology and obtaining pure cultures is essential
for the study of microbial physiology and function. When
isolating microorganisms from aquaculture environments,
Vibrio are the most dominate isolates on the media that are
commonly used. In order to expand our ability to study microbial
species, an easy-operation and low-cost medium that
can reduce the interference of Vibrio strains and increase the
cultivability of other bacteria is urgently needed. We compared
viable cell counts on conventional media (CM; including
Marine Agar 2216 and LB media) and diluted media (DM;
including 1/10-Marine Agar 2216, 1/10-LB). We also assessed
the diversity of cultivable microorganisms under high and
low nutrient conditions by a plate-wash strategy coupled with
high-throughput sequencing of the V4 hypervariable region
of the 16S rRNA gene. The results show that microbial communities
from DM, especially 1/10-Marine Agar 2216, are
more diverse than those obtained from CM. Vibrio isolates
were reduced on DM. PICRUSt analysis revealed that nutrient
composition is a significant contributor to the diversity
and function of the cultivable microbial communities. Bacteria
grown on CM possess more pathogenic characteristics,
whereas DM favors the growth of bacteria that have multiple
metabolic functions. Collectively, our data provide strong evidence
that dilution of CM influences the cultivability of bacteria
from aquaculture seawater. It also supports that DM can
expand the range of microbial species that can be cultivated.
This study also provides insights for media design in microbial
cultivation from aquaculture systems.