Nutritional and physiological responses of finishing pigs exposed to a permanent heat exposure during three weeks

• Published in: Archives of animal nutrition Vol. 68; no. 4; pp. 296 - 308
• Main Authors: Hao, Yue, Feng, Yuejin, Yang, Peige, Feng, Jinghai, Lin, Hai, Gu, Xianhong
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 01.01.2014; Taylor & Francis Ltd
• Subjects: ad libitum feeding; ambient temperature; AMP-activated protein kinase; AMP-Activated Protein Kinases - metabolism; Animal Feed - analysis; Animal Nutritional Physiological Phenomena; Animals; blood serum; body weight changes; cortisol; creatine kinase; crude protein; digestibility; energy; Energy Metabolism; enzyme activity; feed intake; finishing; glycolysis; heat; heat stress; hexokinase; Hot Temperature; lactate dehydrogenase; lactic acid; Male; males; Muscle, Skeletal - metabolism; muscles; physiological response; pigs; pyruvate kinase; respiratory rate; skeletal muscle; Sus scrofa - growth & development; Sus scrofa - physiology; swine; Weight Gain; heat stress; pigs; digestibility; enzyme activity; energy metabolism; glycolysis
• ISSN: 1477-2817; 1745-039X; 1477-2817
• DOI: 10.1080/1745039X.2014.931522

The aim of the current study was to investigate the effect of a permanent heat exposure during 21 days on pig performance, nutrient digestibility, physiological response and key enzyme of skeletal muscle energy metabolism. Twenty-four male finishing pigs (crossbreed castrates, 79.0 ± 1.50 kg body weight) were allocated to three groups (n = 8): (1) Control (ambient temperature (AT) 22°C, ad libitum feeding), (2) Group HE (AT 30°C, ad libitum feeding) and (3) Group PF (AT 22°C, pair-fed to Group HE). The permanent heat exposure decreased feed intake (p < 0.01), daily body weight gain (p < 0.05) and the digestibility of gross energy, dry matter, crude protein and ash (p < 0.05); rectal temperature and respiration rate were significantly increased (p < 0.01). The levels of plasma cortisol, creatine kinase and lactate dehydrogenase were also significantly increased in Group HE (p < 0.05). Furthermore, the heat exposure changed intracellular energy metabolism, where the AMP-activated protein kinase was activated (p = 0.02). This was combined with changes in parameters of glycolysis such as an accumulation of lactic acid (p = 0.02) and a drop of pH ₂₄ ₕ (p = 0.02), an increase of hexokinase and pyruvate kinase activity (p < 0.01) and, finally, the maturation process of post mortem muscle was influenced. Due to pair-feeding it was possible to evaluate the effects of heat exposure, which were not dependent on reduced feed intake. Such effects were, e.g., reduced nutrient digestibility and changed activities of several enzymes in muscle and blood serum.