Using near-infrared reflectance spectroscopy (NIRS) to estimate carbon and nitrogen stable isotope composition in animal tissues

Abstract

<ol>

<li>Stable isotopes analysis (SIA) of carbon and nitrogen provides valuable information about trophic interactions and animal feeding habits.</li>

<li>We used near-infrared reflectance spectroscopy (NIRS) and support vector machines (SVM) to develop a model for screening isotopic ratios of carbon and nitrogen (δ¹³C and δ¹⁵N) in samples from living animals. We applied this method on dried blood samples from birds previously analyzed for δ¹³C and δ¹⁵N to test whether NIRS can be applied to accurately estimate isotopic ratios.</li>

<li>Our results show a prediction accuracy of NIRS (R2 > 0.65, RMSEP < 0.28) for both δ¹³C and δ¹⁵N, representing a 12% of the measurement range in this study.</li>

<li>Our study suggests that NIRS can provide a time- and cost-efficient method to evaluate stable isotope ratios of carbon and nitrogen when substantial differences in δ¹³C or δ¹⁵N are expected, such as when discriminating among different trophic levels in diet.</li>

</ol>