Abstract
Sea stars play important roles in ecosystem health, serve as important research subjects, and are popular display animals. They are frequently anesthetized for veterinary medical procedures and research, yet there have been no published studies to evaluate the clinical efficacy and effects of anesthetic agents on sea stars.1,2 The objective of this study was to assess the clinical response of the small spine sea star (Echinaster spinulosus) to tricaine methanesulfonate (MS-222) at 0.8 g/L3 (n=6) buffered with sodium bicarbonate, using clinical observation, coelomic fluid chemistry, and full thickness body wall biopsies in comparison to sea stars under control conditions (n=6). Righting response was immediately lost following immersion in MS-222, revealing that this response is not a reliable indicator of anesthetic plane in this species. Sea stars failed to respond to tactile stimulation, on average, at 23 minutes (range 10–40 minutes), suggesting potential anesthesia. Sea stars demonstrated behaviors interpreted as indicating immersion in buffered MS-222 was noxious, including arm curling (n=6 of 6) and gastric eversion (n=1 of 6). Two sea stars developed grossly visible body wall lesions following anesthetic immersion, whereas post-procedural complications were absent in the control group. Coelomic fluid of anesthetized sea stars had significantly higher sodium and osmolality compared to control sea stars. No histological differences were identified in visibly normal body wall tissue. Immersion in buffered MS-222 at 0.8 g/L resulted in significant negative effects in small spine sea stars. Alternate anesthetic protocols may be more appropriate for Asteroid anesthesia and further evaluation is warranted.
Acknowledgements
The authors wish to thank the Whitney Marine Laboratory, Kevin Kroll, Dr. Donald Behringer, Dr. Andrew Kane, Dr. Amy Alexander, Sarah Crevasse, Jill Arnold, and Dr. Brent Whitaker for their support and technical assistance.
*Presenting author
+Student presenter
Literature Cited
1. Cooper JE. 2011. Anesthesia, analgesia, and euthanasia of invertebrates. ILAR J 52(2):196–204.
2. Gunkel C, Lewbart GA. 2008. Anesthesia and analgesia of invertebrates. In: Fish RE, Brown MJ, Danneman PJ, Karas AZ, editors. Anesthesia and Analgesia in Laboratory Animals, 3rd edition. Philadelphia (PA): Elsevier Publishing. p 535–546.
3. Applegate Jr, JR, Dombrowski DS, Christian LS, Bayer MP, Harms CA, Lewbart GA. 2016. Tricaine methanesulfonate (MS-222) sedation and anesthesia in the purple-spined sea urchin (Arbacia punctulata). J Zoo Wildl Med 47(4):1025–1033.