中国农业科学Issue(5)：952-958,7.DOI:10.3864/j.issn.0578-1752.2015.05.13
持续高温对育肥猪不同部位脂肪代谢的影响
Influence of Constant High Ambient Temperature on Fat Metabolism of Different Parts in Finishing Pigs
摘要
Abstract
[Objective] The objective of this study is to investigate the effects of constant high ambient temperature on fat metabolism in finishing pigs and to preliminarily explore the mechanism of the impact.[Method] Sixteen Duroc × Landrace × Large White castrated male pigs were randomly assigned into a high-temperature environment (HT group: 30℃,ad libtum) and a normal thermal group (NT group: 22℃,ad libtum) with eight pigs in each treatment. Pigs were housed in individual wire cages under a 14-h lighting schedule and had free access to water. The experiment lasted for 3 weeks, and the temperature kept unchanged during this time. The relative humidity in the room was controlled at (55±5)%. The pigs were electrically stunned and exsanguinated after a 12-h period of feed withdrawal with free access to water at the end of the experiment.[Result] The results of the experiment showed that the carcass weight and backfat depth at 30℃ were lower than that at 22℃, but the differences were not significant (P>0.10). And high ambient temperature had a trend to increase the proportion of flare fat in carcass weight (+22.06%,P=0.07), to decrease the lipid content of longissimus dorsi (LM) (-22.39%,P=0.08). The activities of fatty acid synthase (FAS) (P<0.05) and malic enzyme (ME) (P<0.05) in backfat and flare fat were lower at 30℃ than at 22℃, the amounts of acetyl-CoA-carboxylase (ACC) (P<0.01) and FAS (P<0.05) were decreased in LM in HT group, and the activity of FAS in liver was also inhibited by high temperature (P<0.01). These enzymes (ACC, FAS, ME) were key ones inde novo synthesis of the fatty acids, above results indicated that high ambient temperature inhibitedde novo synthesis of fatty acids in adipose tissues. High ambient temperature had no significant effects on the content of hormone-sensitive lipase (HSL) in all adipose tissues (P>0.10). High ambient temperature significantly increased the content of LPL in flare fat (P=0.05), and decreased the content of LPL in LM (P=0.05). The rule how high ambient temperature influenced fat deposition of the three parts was in accordance with the rule how high ambient temperature influenced the contents of LPL in the same part, which means that high ambient temperature may influence the fat deposition by regulating the content of LPL. The activities ofβ-hydroxyacyl coenzyme A dehydrogenase (HAD) at the front (P<0.05) or back (P<0.01) of LM were lower at 30℃ than at 22℃, and the enzyme of HAD is a key one in theβ-oxidation of fatty acids, the findings indicated that high temperature inhibited fatty acid oxidation in skeletal muscle. High ambient temperature significantly increased the content of cAMP in LM (P<0.01), but had no significant effects on the content of cAMP in backfat and flare fat (P>0.10). The plasma concentration of nonesterified fatty acid (NEFA) was higher (P<0.05), and very low density lipoprotein (VLDL) tended to be higher at 30℃ than at 22℃ (P=0.07). High ambient temperature had no significant effects on the plasma concentration of total cholesterol (CHOL), triglyceride (TG), high density lipoprotein-cholesterol (HDL-C) and low density lipoprotein-cholesterol (LDL-C) (P>0.10).[Conclusion]The results demonstrated that high ambient temperature had different effects on adipose tissues in different parts. High ambient temperature may influence fat deposition in different parts by regulating the content of LPL in different parts. High ambient temperature depressedde novo fatty acid synthesis in adipose tissues and in the liver. However,β-oxidation of fatty acid in skeletal muscles was also inhibited in the high-temperature environment, which may result in an increased concentration of NEFA in the plasma, and NEFAs were esterified to synthesize VLDLs in the liver, reabsorbed by adipose tissues ultimately. But the mechanism that plasma concentrations of NEFA and VLDL were higher in the high-temperature needs to be further studied.关键词
持续高温/育肥猪/脂肪组织/脂肪代谢Key words
constant high ambient temperature/finishing pigs/adipose tissues/fat metabolism引用本文复制引用
吴鑫,冯京海,张敏红,苏红光,贾安峰..持续高温对育肥猪不同部位脂肪代谢的影响[J].中国农业科学,2015,(5):952-958,7.基金项目
国家“973”计划（2012CB124700）、中国农业科学院科技创新工程 （）
