Effects of Metomidate Hydrochloride Sedation on Blood Glucose and Marketability of Transported Threespot Gourami Trichogaster trichopterus

Abstract

Our objectives were to determine whether sedation with metomidate hydrochloride (hereafter, “metomidate”) during transportation of threespot gourami Trichogaster trichopterus would prevent an increase in blood glucose levels and improve fish marketability (i.e., based on appearance and behavior) in comparison with unsedated controls. Threespot gourami are obligate air-breathers that possess a labyrinth organ, enabling the fish to respire air above the water surface; these fish should be lightly sedated during transport. Fish were transported for approximately 24 h via truck and domestic airline. Blood was sampled at 0, 2, 6, and 12 h posttransportation, and appearance and behavior were observed at 0, 2, 4, 6, and 12 h and 7 d posttransportation. Metomidate concentrations tested were 0.0 (control), 0.1, 0.2, 0.3, and 0.4 mg/L. At the concentrations tested, metomidate neither inhibited elevations in blood glucose nor improved marketability. Fish that were transported with 0.3-mg/L metomidate were less marketable based on behavioral indices, and fish that were transported with 0.4-mg/L metomidate had higher glucose levels than control fish. Use of metomidate as a transport sedative for threespot gourami should be considered with caution and may be problematic at the concentrations tested; however, further research examining additional indices of stress may clarify metomidate use for this species.

Received February 16, 2011; accepted December 18, 2011.

ACKNOWLEDGMENTS

This study was part of a Master of Science research project conducted wholly at the University of Florida. Funding was provided by the Cooperative State Research, Education, and Extension Service of the U.S. Department of Agriculture. We thank Syndel Laboratories Ltd. for providing Aquacalm; 5-D Tropical, Inc. for providing fish; and Segrest Farms (Gibsonton, Florida) for transporting the fish. We are also grateful to Jamie Holloway, Paul Anderson, Jenney Kellogg Lazzarino, Matthew DiMaggio, and Meghan Brennan (University of Florida) for their assistance. We thank the anonymous reviewers for their helpful comments on the manuscript. This research was conducted under Project Number E186 of the Institutional Animal Care and Use Committee, University of Florida.