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Effects of heat stress on energetic metabolism in growing pigs
Author(s) -
Pearce Sarah Christine,
Upah Nathan C,
Harris Amanda,
Gabler Nicholas K,
Ross Jason W,
Rhoads Robert P,
Baumgard Lance H
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.1052.5
Subject(s) - nefa , adipose tissue , zoology , medicine , endocrinology , crossbreed , metabolism , chemistry , biology , insulin
To delineate differences between heat stress (HS) and decreased feed intake on energetic metabolism we utilized crossbred gilts (n=48; 35±4 kg BW) which were housed in constant climate controlled rooms in individual pens and exposed to 1) thermal neutral (TN) conditions (20°C; 35–50% humidity) with ad libitum intake (n=18), 2) HS conditions (35°C; 20–35% humidity) with ad libitum intake (n=24) or 3) pair‐fed (PF in TN conditions [PFTN], n=6: to eliminate confounding effects of dissimilar feed intake). Pigs were sacrificed at 1, 3, or 7d of environmental exposure. Pigs exposed to HS had an increase in rectal temperature (39.3 vs. 40.8°C). On d1, HS pigs had a 67% increase in plasma NEFA, but NEFA concentrations rapidly declined and did not differ from TN pigs on d3 or 7. PFTN pigs had a 157% increase in plasma NEFA on d7 compared to TN and HS counterparts. On d7, HS pigs had increased (86%) plasma insulin concentrations compared to PFTN pigs. Subcutaneous adipose tissue FAS activity tended ( P <0.11) to be increased on d7 in HS compared to PFTN pigs but G3PDH activity did not differ between treatments. On d7, adipose tissue HSL gene expression tended to be decreased ( P <0.11) in HS compared to PFTN pigs, but LPL mRNA abundance did not differ between treatments. Our data indicate HS markedly alters post‐absorptive carbohydrate and lipid metabolism and many of these physiological changes are independent of reduced nutrient intake.