Abstract

Hematologic evaluation is well established as an important diagnostic tool in vertebrate species; however, comprehensive evaluation of invertebrate hemolymph is lacking. The objective of this study was to establish baseline hemolymph parameters including hemocyte concentrations, cellular morphology and biochemistry values in Japanese spider crabs (Macrocheira kaempferi). It was hypothesized that hemocytes would bear resemblance to those described for blue crabs (Callinectes sapidus) and that biochemistry results would closely mimic water chemistry values.¹ Five apparently healthy M. kaempferi underwent physical examination and hemolymph sampling. Total hemocyte counts (THC) ranged from 10.3 to 19.9x10³ cells/μL. Three distinct hemocytes were identified, including agranulocytes, semi-granulocytes and granulocytes. Plasma biochemistry analysis indicated elevated sodium, calcium and aspartate aminotransferase (AST) as well as decreased glucose, total protein, and alkaline phosphatase (ALP) concentrations compared to horseshoe crabs (Limulus polyphemus).² Pre-molt, gravid M. kaempferi had a higher THC, phosphorus, total protein, amylase, and cholesterol values when compared to post-molt, non-gravid females and post-molt males. This study established protocols for collection, processing, and interpretation of hemolymph in M. kaempferi, including the first identification of hemolymph cell types in this species. This data increases the clinical utility of hemolymph analysis by providing baseline values with which to compare during routine physical examinations as well as during disease investigations in managed populations. In addition, these results may allow for early identification of egg production and impending molt, such that management and husbandry changes can occur to ensure proper environmental stimulus to promote these normal physiological processes.

Acknowledgements

The authors wish to thank Dr. Barbara Mangold, Gayle Sirpenski, Amy Delmonaco, Stephanie Golding, and William Hana of Mystic Aquarium, Jill Arnold of ZooQuatic Laboratory LLC, and Trevor Erdmann of the Oregon Coast Aquarium for technical assistance and their support of this project.

* Presenting author
+ Student presenter

Literature Cited

1.  Wenli C, Shields JD. 2007. Characterization and primary culture of hemocytes from the blue crab Callinectes sapidus. In: Cai SL, editor. 5th World Chinese Symposium for Crustacean Aquaculture, vol. 5. Beijing (China): Ocean Press. p 25–35.

2.  Smith SA, Berkson JM, Barratt RA. 2002. Horseshoe crab (Limulus polyphemus) hemolymph, biochemical and immunological parameters. IAAAM 33rd Annual Conference Proceedings, Albufeira, Portugal; Pp. 101–102.