Proteomic analysis of physiological function response to hot summer in liver from lactating dairy cows

Data-independent acquisition-based proteome profiling of red blood cells from dairy buffaloes under different types of heat stress

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.

Jejunal mucosa proteomics unravel metabolic adaptive processes to mild chronic heat stress in dairy cows

Climate change affects the duration and intensity of heat waves during summer months and jeopardizes animal health and welfare. High ambient temperatures cause heat stress in dairy cows resulting in a reduction of milk yield, feed intake, and alterations in gut barrier function. The objectives of this study were to investigate the mucosal amino acid, glucose and lactate metabolism, as well as the proteomic response of the small intestine in heat stressed (HS) Holstein dairy cows. Cows of the HS group (n = 5) were exposed for 4 days to 28 °C (THI = 76) in a climate chamber. Percentage decrease in daily ad libitum intake of HS cows was calculated to provide isocaloric energy intake to pair-fed control cows kept at 15 °C (THI = 60) for 4 days. The metabolite, mRNA and proteomic analyses revealed that HS induced incorrect protein folding, cellular destabilization, increased proteolytic degradation and protein kinase inhibitor activity, reduced glycolysis, and activation of NF-κB signaling, uronate cycling, pentose phosphate pathway, fatty acid and amino acid catabolism, mitochondrial respiration, ATPase activity and the antioxidative defence system. Our results highlight adaptive metabolic and immune mechanisms attempting to maintain the biological function in the small intestine of heat-stressed dairy cows.