From Saliva to Faeces and Everything in Between: A Guide to Biochemical Analysis Using Animal Samples for Biomarker Detection

Abstract

Clegg and Millsonenormous breadth of the review, we have provided general examples and citations for more specific examples covering the major sample types, commonly used biomarkers, and biochemical assays. The goal of the review is to provide a first resource for researchers interested in studying biomarkers to complement behavioural analysis. This article should not be considered a complete guide. We urge readers who are planning to use any of the techniques described here to read more detailed information in the many publications we have cited, because many of our general rules of thumb may not apply to specific implementations. Choosing the Ideal SampleSelecting the ideal physical sample is incredibly important. Although most assays are available to run either on site or in a laboratory, this may not be the case for all samples. The selection of sample type is dependent on the biomarker(s) to be measured, the types of assays available to measure these biomarkers (see the Types of Biochemical Test section for further information), and the ability/ availability to collect the sample type. Availability will depend on many factors, not least the ability to collect invasive samples, such as blood, and the research project questions/aims (Mormède et al., 2007). It is important to mention that the correct ethical and legal licences must be in place before samples are obtained from animals. In addition, licences may also be needed for working with certain species, such as Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) species, or for transportation of samples across borders or into countries because of biosecurity concerns (Animal Science Procedure Act [ASPA], 1986). As an example, a schematic diagram for selecting the ideal sample for studying stress responses is shown in Figure 1.

Quality of hematology and clinical chemistry results in laboratory and zoo nonhuman primates: Effects of the preanalytical phase. A review

“…The latter has long been restricted to blood analyses, which are considered as non-or minimally invasive in human clinical pathology, but are not in animals. This explains the growing interest in noninvasive sampling of urine, feces, saliva, and hair, which requires taking their particularities and limitations into account [3][4][5][6] (review in Behringer 2017 7 ).…”

The Importance of Monitoring Cortisol in the Agri-Food Sector—A Systematic Review

“…Typically, cortisol is measured in blood plasma, tissue, or whole-body extracts, being considered an invasive process due to the inducement of stress caused by handling and, consequently, the production of the hormone within minutes that could easily bias the basal cortisol estimations. Non-invasive methods have emerged through detecting cortisol on other matrices, such as urine, feces, and saliva, to avoid that situation [ 7 , 8 ]. Despite being non-invasive for the species, accurately measuring cortisol requires rapid sample collection to prevent steroid degradation or contamination due to cortisol in the water, food debris or plant hormones, and the cortisol excretion in biological samples such as feces can be affected by the gut microbiota or by bacteria in the urine.…”

“…Despite being non-invasive for the species, accurately measuring cortisol requires rapid sample collection to prevent steroid degradation or contamination due to cortisol in the water, food debris or plant hormones, and the cortisol excretion in biological samples such as feces can be affected by the gut microbiota or by bacteria in the urine. Moreover, several freeze–thaw cycles can alter the hormones’ concentration [ 3 , 8 ].…”