Cervical mucus proteomics approach for swamp buffalo secreted fertility biomarker identification

Reproductive efficiency in swamp buffalo (Bubalus bubalis) remains constrained by the lack of molecular tools to identify fertile females before service. The aim of this study was to discover biologically grounded biomarkers of fertility.

Cervical mucus was profiled using high-resolution proteomic analysis, with quantitative and functional enrichment used to prioritise biologically relevant fertility markers.

The cervical-mucus proteome exhibited a conserved secreted core with marked quantitative shifts that separated favourable-quality from poor-quality mucus. Favourable mucus was characterised by a barrier- and adhesion-associated profile with antimicrobial and antioxidant features, its proteins including integrin/extracellular matrix interactors, redox enzymes, lipocalin 2 (LCN2), secretory leukocyte protease inhibitor (SLPI) and heat-shock protein B6 (HSPB6). Poor mucus showed a neutrophil-acute-phase axis with complement engagement and oxidative chemistry, typified by myeloperoxidase (MPO), pentraxin 3 (PTX3) and C-reactive protein (CRP). Functional enrichment emphasised extracellular and host-defence processes consistent with these opposing mucosal states. These six proteins were consistently the leading discriminants and had coherent biological roles.

Swamp-buffalo cervical mucus is variously in a barrier-competent state and a neutrophil-dominant state. This dichotomy provides a mechanistic explanation for fertility differences at the cervix and yields actionable, secreted protein biomarkers - LCN2/SLPI/HSPB6 in favourable mucus and MPO/PTX3/CRP in poor mucus - for targeted assays and pre-service screening in tropical production systems.