Spectral pattern of urinary water as a biomarker of estrous

Abstract

Although the assay of hormones associated with the reproductive physiology is essential to estimate the estrous status, the assay takes about one day to process and requires expensive reagents. Therefore, monitoring of additional objective indexes related to estrous is useful for quick determination of the optimal timing for breeding. Here we apply near infrared (NIR) spectroscopy of urine for evaluation of female estrous. Near infrared spectroscopy has been developed as a non-invasive, rapid, and chemical-free tool in biological sciences. We reported that characteristic water absorbance patterns based on 12 specific water absorbance bands in the first overtone wavelength region display high urine spectral variations, suggesting that hydrogen-bonded water structures increase with estrus1. The result presents the water spectral pattern of urine as a biomarker and near infrared spectroscopy coupled with aquaphotomics as a new platform for estrous diagnosis.