Abstract
Heat stress (HS) induces hypoxia and oxidative stress, reducing animal health and livestock production. Red blood cells (RBCs) are responsible for oxygen delivery, and are susceptible to HS. In this study, 12 healthy buffaloes with a similar body condition, lactation, and parity were raised under thermal-neutral (TN) conditions. After the collection of blood samples, buffaloes were randomly and equally divided into two groups. Six buffaloes underwent acute HS conditions for eight days (AHS group). Subsequently, these six AHS buffaloes were subjected to chronic HS conditions (AHS-CHS group). The other six TN buffaloes were raised under chronic HS conditions (CHS group). RBCs were isolated for data-independent acquisition-based proteomics to identify differentially expressed proteins involved in the HS response. Results showed that blood clotting factors, complements, immunoglobulins, and vasoconstriction proteins in RBCs were consistently decreased under the three types of HS conditions (AHS, AHS-CHS, and CHS). Moreover, the immunity of buffaloes experiencing AHS (AHS and AHS-CHS) was severely decreased when compared to those subjected to CHS. Due to high heat sensitivity of RBCs, AHS conditions should be avoided for dairy buffaloes in summer.