Modeling the fate of dietary 17B-estradiol and its metabolites in an American eel (Anguilla rostrata) recirculating aquaculture system

Yuri Park, Abdullah Alayafi, Jessica L. Bennett, David Malloy, Paul M. Smith, Neil W. Ross, Graham A. Gagnon, Adam A. Donaldson

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

Recirculating aquaculture system (RAS) is being applied in many aquaculture industries as it provides an opportunity to produce fish in a contained system with minimal use of water. In proposed RAS-based farming of the American eel, 17β-estradiol (E2) is being investigated as an in-feed drug to feminize and increase growth of farmed eels. This creates potential for release of E2 and its metabolites from the eel RAS and information is needed to monitor and manage eel farm effluents to reduce impact on the environment. In the current study, the concentrations of E2 and its metabolites (i.e., estrone (E1) and estriol (E3)) were monitored from different compartments in the RAS and analyzed by liquid chromatography tandem mass spectrometry (LC–MS/MS). E2 levels ranged from 8 to 25 ng/L in the water recirculating within the RAS and declined to 2–6 ng/L in the weeks post-treatment. E1 levels were within similar ranges as E2, whereas E3 levels were below 2 ng/L throughout the study. The results were used to develop a computational model to describe the fate of E2 and its metabolites in the RAS, and to delineate the influences of metabolism and hydrodynamics for the removal of E2 by RAS processes. The rapid removal of uneaten feed and feces downstream of inventory tanks was found to be the most significant mechanism for the removal of 2–6% of the E2 added in feed daily, producing a concentrated effluent stream suitable for strategic treatment strategies. Greater than 94% of E2 added to the system with feed was either metabolized by the eels and/or bacteria in the biofilters of the RAS or was sufficiently bound to solids fractions in the solid samples to resist organic extraction and detection. Additionally, reducing daily water exchange from 23 to 7% of the system water inventory resulted in an increase of only 1 ng/L in E1 concentrations within the RAS system while a negligible change in the concentration of E2 was observed.

Original languageEnglish
Article number101995
JournalAquacultural Engineering
Volume86
DOIs
Publication statusPublished - Aug 2019

Bibliographical note

Funding Information:
This work was funded through Productivity and Innovation Voucher Program of the Government of Nova Scotia . Helpful comments and advice from Dr. Allison Mackie were appreciated. As well, the authors would like to thank the staff of the Dalhousie Aquatron for RAS modifications to allow for sampling. We acknowledge the technical expertise provided by Heather Daurie and Nicole Allward throughout this study. We would also like to thank Dr. Tom MacRae for generously allowing us to use his laboratory and equipment for feed preparation and method development.

Publisher Copyright:
© 2019 Elsevier B.V.

ASJC Scopus Subject Areas

  • Aquatic Science

Fingerprint

Dive into the research topics of 'Modeling the fate of dietary 17B-estradiol and its metabolites in an American eel (Anguilla rostrata) recirculating aquaculture system'. Together they form a unique fingerprint.

Cite this