Serum proteomics analysis reveals the thermal fitness of dairy buffalo to chronic heat stress

Abstract Background: Chronic heat stress (CHS), aggravated by global warming, reduces the production efficiency of the buffalo dairy industry. CHS changes protein abundance, and low-abundant proteins take important roles in biological processes. Results: The objective of the study was to assess differences in low-abundant serum proteins in dairy buffaloes at thermoneutral (TN) or under chronic heat stress (CHS) conditions with proteomic approaches. Six dairy buffaloes as reference animal raised in TN season, and another six dairy buffaloes raised in CHS to discover the molecular mechanism of thermal fitness in hot season with serum proteomics. After the removal of multiple high-abundant proteins in serum, 344 low-abundant proteins were identified in serum with label-free quantification. Of these, 17 low-abundant differentially expressed serum proteins with known functions were detected, and five of these differentially expressed proteins were validated with parallel reaction monitoring. These five proteins were associated with various aspects of heat stress, including decreased heat production, increased blood oxygen delivery, and enhanced natural disease resistance. Conclusions: Lipase (LPL), glutathione peroxidase 3 (GPX3), cathelicidin-2 (CATHL2), ceruloplasmin (CP), and hemoglobin subunit alpha 1 (HBA1) were shown to play cooperative roles in CHS fitness in dairy buffalo. Dairy buffaloes adapt to CHS and hypoxia with high levels of RBCs, HBA1 and CP increased blood oxygen delivery capacity and thermal fitness.