aquaculture-summit-2017-scientifictracks-abstracts

7 / 29

Page 29
Notes:
conferenceseries.com
Volume 5, Issue 2 (Suppl) J Fisheries Livest Prod
ISSN: 2332-2608 JFLP, an open access journal Aquaculture Summit 2017
May 25-26, 2017
May 25-26, 2017 Osaka, Japan
6th Global Summit on
Aquaculture and Fisheries 2017
Possibility of marine eukaryote, thraustochytrids as novel probiotic candidates in aquaculture
Yousuke Taoka
University of Miyazaki, Japan
World aquaculture production has continued to increase. Fishmeal is used as protein sources for aqua-feeds. However, the
price is drastically increased to around 170,000/ ton in 2013 during recent 10 years because of the decrease of fish resources,
anchovy. This is serious problem for sustainable aquaculture. Therefore replacement of fishmeal to another resource is urgently
needed. Several researchers reported the replacement of protein sources from fishmeal to plants. However, the complete replacement
by plant proteins is not established yet because plant sources contained some components that negatively affect the growth of the
cultured fish due to the low digestibility. We focused on the “thraustochyrids” as probiotics to enhance the digestibility of plant
sources. Thraustochytrids are widely distributed in marine environment and have unique characteristics that accumulate large
amount of lipids in cell bodies. Additionally, it is known that thraustochytrids produce various extracellular enzymes including
refractory components such as cellulose. In this study, we researched the profile of extracellular enzymes from thraustochytrids
and the tolerant ability in the gastrointestinal juices in vitro and in vivo to evaluate the potency as probiotics. Production of various
extracellular enzymes, protease, amylase, lipase (tween 80 hydrolytic enzyme), cellulase and tannase were detected depending on the
genus or species of thraustochytrids. The tolerance to artificial gastric juices was high in genus Aurantiochytrium and Ulkenia, and
low in genus Oblongichytrium. In the case of in vivo test, Aurantiochytrim was recovered from the intestine of Japanese short-necked
clam, Ruditapes philippinarum (“Asari” in Japanese). Additionally, we have isolated more than one hundred thraustochytrids from
marine environment and are screening probiotic abilities to select adequate strain now. As next step, we are planning the rearing trial
with aquaculture-major fish species and supply live thrautochytrids by oral administration.
Biography
Yousuke Taoka has completed his PhD from the United Graduate School of Agricultural Sciences, Kagoshima University and Post-doctoral studies from University
of Miyazaki. He worked in a commercial fisheries company, Nippon Suisan Kaisha, Ltd. as a Researcher and joined University of Miyazaki in 2011. Recently, he
has focused on the production of functional substances from marine microbes and the utilization in the field of aquaculture.
Yousuke Taoka, J Fisheries Livest Prod 2017, 5:2 (Suppl)