Heat stress and reduced feed intake alter the intestinal proteomic profile (246.1)

Abstract

Heat stress (HS) and reduced feed intake have been shown to negatively affect intestinal integrity and barrier function. Our objective was to compare ileum protein profiles of pigs subjected to HS, thermal neutral (TN), or reduced feed intake conditions. Twenty‐four pigs (n=8/treatment) were assigned to one of these treatments for 12 h: 1) TN (21°C; 70% humidity with ad libitum intake, 2) HS (37°C; 40% humidity with ad libitum intake), or 3) TN conditions but pair fed (PFTN) to mirror nutrient intake of the HS pigs. Pigs were then euthanized, whole ileum was collected, and protein extracted. Proteins were solubilized and 2D‐Differential In Gel Electrophoresis (DIGE; 24 gels in duplicate), 11cm strips pH 3‐10, in the first dimension and 12.5% acrylamide gels in the second dimension, was performed. Relative abundance of 281 and 138 proteins were significantly different (P < 0.05) due to HS, compared to TN and PFTN pigs respectively. However, only 20 proteins were significantly different due to reduced feed intake alone (P < 0.05). Differentially expressed proteins were identified by electrospray mass spectrometry (ESI/MS). Compared to TN and PFTN pigs, heat shock proteins 27, 70, 90‐α and β were increased during HS. However, metabolic enzymes isocitrate dehydrogenase and glyceraldehyde‐3‐phosphate dehydrogenase were decreased in HS pigs (75 and 10% respectively; P < 0.05) compared to TN and PFTN pigs. Similarly, stress response enzymes peroxiredoxin‐1 and peptidyl‐prolyl cis‐trans isomerase A were decreased (40 and 15% respectively; P < 0.05) in PFTN and TN pigs compared to HS. Interestingly, prolyl‐4‐hydroxylase‐β was reduced 10% in HS and PFTN pigs compared to TN controls. Together, these data show that HS directly alters intestinal protein profiles during a severe heat‐load, largely independent of reduced feed intake.Grant Funding Source: Supported by USDA‐AFRI grant# 2011‐67003‐30007