Untargeted Urine Metabolomics Profiling during Different Phases of Estrous Cycle in Surti Goats

Background: Estrus detection is crucial for reproductive performance of goats which requires accurate, economical and easy techniques. Present study was undertaken to delineate urine metabolomics profile to identify biomarkers for different phases of estrous cycle in Surti goats. Methods: Ten non-pregnant Surti goats were synchronized for estrous using intra-vaginal progesterone sponges (impregnated with 60 mg Medroxyprogesterone acetate) for 11 days followed by intramuscular injection of 125 μg Cloprostenol (PGF2a analogue). Estrus was confirmed based on physiological and behavioral signs. Urine samples collected during proestrus, estrus and diestrus were analyzed using gas chromatography-mass spectrometry. Web-based interface MetaboAnalyst 5.0 was used for data preprocessing, normalization, statistical analysis and data visualization. Statistical analysis comprised data normalization, one-way ANOVA and post-hoc Fisher LSD test, hierarchical clustering, principal component analysis and partial least squares discriminant analysis. Result: Total 56 metabolites were found to vary during different phases of estrous cycle. The study was successful in generating untargeted urine metabolomics profile of Surti goats that can be used for identifying specific biomarkers for different phases of estrous. Two metabolites 4-amino-2-hydroxybenzoic acid (2-dieth-4-A-2) and 4-Methylphenol (p-Cresol) emerged as potential biomarkers for detecting estrus. These results can serve as base line reference paving way for future studies in larger group that may further validate these findings.