Abstract

Supplementation of exotic species diets under human care with purified singular micronutrients often occurs in response to serum values found outside of established reference ranges. While true normal healthy values are not always established for exotic species, literature may exist,² or domestic species models are utilized to start comparisons. There are situations where supplementing a deficient nutrient is appropriate, but often a more optimal dietary balance can avoid the need for specific supplementation. A paucity of data exists regarding nutrient bioavailability in varied species, contributing to the potential lack of result when a single nutrient is provided orally to impact serum concentrations; however, while attempting to interpret supplementation, reliability and trust in laboratory analysis is critical. This becomes important based on variations in sample preparation and methodologies used for analysis including LC-MS-MS, HPLC, and ICP-MS.^1,3 Recent studies testing α-tocopherol in controlled split longitudinal samples of elephant and rhino serum found extreme variation and lack of correlation (r=0.02; r=0.14; respectively) when compared between and within laboratories.^4-6 The Veterinary Laboratory Investigation and Response Network (Vet-LIRN) of the FDA also conducted proficiency evaluations for vitamin E across laboratories, and found challenges with reliability of some laboratories at minimal levels (<0.88 µg/dl α-tocopherol; unpublished 2016). Pachyderms and other exotic species with commonly low tocopherol values may warrant further laboratory control testing before supplementation. Basic quality control testing is recommended, including sending blind duplicate samples, repeated split samples across time, or utilizing the National Institute of Standards and Technology controls.

Literature Cited

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2.  Dierenfeld ES, Traber MG. Vitamin E status of exotic animals compared with livestock and domestics. In: Pacher L, Fuchs J, eds. Vitamin E in Health and Disease. New York, NY: Marcel Dekker Inc.; 1992;30:345–370.

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6.  Sullivan KE, Livingston S, Williams S, Valdes EV. A comparison of commercial laboratories for vitamin E analysis in African elephants (Loxodonta africana). In: Proc Comp Nutr Soc 11th Biennial Symp. 2016:85–86.