Abstract

Cobalamin and folate are water-soluble vitamins that are important indicators of chronic gastrointestinal (GI) function in humans and animal species.^1-3 Deficiency or excess of these vitamins may be a sequela of GI disease when the disease is associated with malabsorption or from overgrowth of bacteria that are capable of producing or binding them.² For cetaceans in human care, diagnosis of GI disease can often be difficult due to an inconsistent clinical presentation. If cobalamin and folate concentrations are similarly affected by GI disease in cetaceans, they may provide a noninvasive tool for detection of GI disease. The objectives of this research were to describe reference ranges for serum cobalamin and folate concentrations in an ex situ population of killer whales (Orcinus orca), and to identify factors that may affect their serum concentrations. We analyzed samples from ten killer whales of both sexes (ages 11 months to 48 years) in good health status and during periods of clinical disease as diagnosed by behavioral changes and fecal cytology. Individual, age, weight, sex, clinical signs of GI upset, and abnormal cytology were included in the analysis. A mixed model logistic regression was used to account for repeated measures within individual animals. Only weight and season had significant relationships with folate levels, with winter (32.9 ± 2.6 µg/ml) having significantly higher folate levels than the other seasons (spring 29.3 ± 2.5 µg/ml, summer 29.5 ± 2.5 µg/ml, and fall 28.9 ± 2.6 µg/ml). Folate was not associated with presence of GI clinical signs. Weight and presence of clinical signs were related to cobalamin levels, with animals presenting with clinical signs (602.2 ± 46.9 µg/ml) having significantly lower cobalamin concentrations compared to healthy animals (731.6 ± 39.1 µg/ml). While our results suggest that cobalamin may be a useful tool in identifying gastrointestinal disease in killer whales, the significant inter-animal variation suggests that comparing an individual's cobalamin level to its own previously healthy values may be the most clinically relevant.

Acknowledgements

The authors would like to thank the Gastrointestinal Laboratory at the Texas A&M College of Veterinary Medicine and Biological Sciences and the laboratory and technical staff at SeaWorld of California.

* Presenting author
⁺ Student presenter

Literature Cited

1.  Andrew T, Gill R, Gillham-Nasenya I, Ahmadi KR. Unravelling the basis of variability in cobalamin levels in the general population. Br J Nutr. 2013;110:1672–1679.

2.  Berghoff N, Steiner JM. Laboratory tests for the diagnosis and management of chronic canine and feline enteropathies. Vet Clin North Am Small Anim Pract. 2011;41:311–328.

3.  Grutzner N, Cranford SM, Norby B, Suchodolski JS, Steiner GM. J Vet Diagn Invest. 2012;24:1105.