Protein and Cholesterol Electrophoresis of Plasma Samples from the Cownose Ray (Rhinoptera bonasus)
Basic research studies have detailed the lack of albumin and a dominance of lipoproteins in the blood of elasmobranchs.1,3 Protein electrophoresis has become a common and valuable tool available in many veterinary reference laboratories.2 This semi-automated platform can also be used to define other analytes including cholesterol fractions. In the present study these methods have been implemented to examine the plasma from the cownose rays (Rhinoptera bonasus) under human care. Plasma protein electrophoretograms revealed a lack of albumin, poorly defined fractions with alpha migration characteristics, and well-defined fractions with beta and gamma globulin migration characteristics. Cholesterol electrophoretograms revealed a dominance of very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) with a poorly defined high-density lipoprotein (HDL) fraction. Two groups of samples were examined. The first represented animals managed under long-term care (n=33) and the second represented animals that were wild caught, with samples collected immediately post-transport (n=43). The total solids concentration was significantly higher in the first group but differences in percent beta and gamma globulins were not significant. The cholesterol level was significantly lower in the transport group. This was reflected in a lower VLDL level. These preliminary results support the premise that these methods can be used in elasmobranchs. Future studies should address species specific reference interval generation and possible sex, age, husbandry, and seasonal differences. Examination of samples from clinically abnormal animals will best gauge the application of these tools in research studies and animal management.
We are grateful to the Georgia Aquarium husbandry team for their excellent animal care and the veterinary team for sample collection and processing.
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2. Kaneko JJ. Serum proteins and the dysproteinemias. In: Kaneko JJ, Harvey JW, Bruss ML, eds. Clinical Biochemistry of Domestic Animals. San Diego, CA: Academic Press; 1997:117–138.
3. Metcalf VJ, Gemmell NJ. Fatty acid transport in cartilaginous fish: absence of albumin and possible utilization of lipoproteins. Fish Physiol Biochem. 2005;31(1):55–64.