Campus Units

Animal Science

Document Type

Article

Publication Version

Accepted Manuscript

Publication Date

12-2018

Journal or Book Title

American Journal of Physiology-Regulatory, Integrative and Comparative Physiology

Volume

315

Issue

6

First Page

R1096

Last Page

R1106

DOI

10.1152/ajpregu.00404.2017

Abstract

Heat-stressed pigs experience metabolic alterations, including altered insulin profiles, reduced lipid mobilization, and compromised intestinal integrity. This is bioenergetically distinct from thermal neutral pigs on a similar nutritional plane. To delineate differences in substrate preferences between direct and indirect (via reduced feed intake) heat stress effects, skeletal muscle fuel metabolism was assessed. Pigs (35.3 ± 0.8 kg) were randomly assigned to three treatments: thermal neutral fed ad libitum (TN, 21°C, n=8), heat stress fed ad libitum (HS, 35°C, n=8), and TN, pair-fed to HS intake (PF, n=8) for 7 days. Body temperature (TB) and feed intake (FI) were recorded daily. Longissimus dorsi muscle was biopsied for metabolic assays on days -2, 3, and 7 relative to initiation of environmental treatments. Heat stress increased TB and decreased FI (P < 0.05). Heat stress inhibited incomplete fatty acid oxidation (P < 0.05) and did not alter glucose oxidation. Metabolic flexibility decreased in HS pigs compared to TN and PF controls (P < 0.05). Both phosphofructokinase and pyruvate dehydrogenase (PDH) activities increased in PF (P < 0.05), however, TN and HS did not differ. Heat stress inhibited citrate synthase and beta hydroxyacyl-CoA dehydrogenase (βHAD) activities (P < 0.05). Heat stress did not alter PDH phosphorylation or carnitine palmitoyltransferase 1 abundance, but reduced acetyl-CoA carboxylase 1(ACC1) protein abundance (P < 0.05). In conclusion, HS decreased skeletal muscle fatty acid oxidation and metabolic flexibility, likely involving βHAD and ACC regulation.

Comments

This is a manuscript of an article published as Zhao, Lidan, Ryan P. McMillan, Guohao Xie, Samantha GLW Giridhar, Lance H. Baumgard, Samer El-Kadi, Joshua Selsby et al. "Heat stress decreases metabolic flexibility in skeletal muscle of growing pigs." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 315, no. 6 (2018): R1096-R1106. doi: 10.1152/ajpregu.00404.2017. Posted with permission.

Copyright Owner

American Physiological Society

Language

en

File Format

application/pdf

Published Version

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