Interpreting vitamins and mineral concentrations in serum of exotic species: lab values are not infallible

Citation

Sullivan KE, Livingston S, Kerr K, Valdes EV.  2015.  Interpreting vitamins and mineral concentrations in serum of exotic species:  lab values are not infallible.  In Bissell H, Brooks M Eds. Proceedings of the Eleventh Conference on Zoo and Wildlife Nutrition, AZA Nutrition Advisory Group, Portland, OR.

Abstract

The prospect of trust and laboratory analysis is often so frightening a concept, scientists in the zoo field, including nutritionists and veterinarians, do not discuss it as more than a side note. Often we trust that specialists in biochemistry and new analysis technologies ensure proper verification of lab methodology, and would inform the consumer of any difficulties or questionable data. In a field where species’ serum normals are generally not well established, serum data from animals under human care can be one of the major indicators used to judge health. Supplementation plans are developed and medical actions taken, based on serum indices- generally taken as fact and at face value as truth. Correct interpretation of nutritional serum parameters is one layer of possible error. However, commercial laboratories are not without human and instrumentation error as well. Use of equipment such as inductively coupled plasma emission spectrometer (ICP-ES) for mineral analysis, and high performance liquid chromatography (HPLC) for vitamin analysis need not only automated systems, but skilled technicians. Communication regarding samples (frozen, level of hemolysis, use of dilution, etc.), and general attention to detail in results is paramount for animal caretakers to interpret results accurately. Interpreting samples requires knowledge of best method of analysis, and factors affecting meaning – such as whole red blood cell manganese being the best indicator of Mn levels. Therefore, while lab error may be a consideration, other factors such as hemolysis may be affecting the wide range of seemingly improbably high levels observed (normal levels of Mn in cattle: 5.0 – 6.0 ng/ ml; sheep: 1.8 – 2.0 ng/ml; pig: 3.0 – 4.0; (Underwood and Suttle, 1999); horse: ~6.0 (Puls, 1994; Figure 1 and 2).

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