[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) (P0.10). 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 (P0.10). The plasma concentration of nonesterified fatty acid (NEFA) was higher (P0.10).[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.%【目的】研究持续高温对育肥猪脂肪代谢的影响并初步探讨影响的机制。【方法】选用16头（79.6±1.2）kg的健康杜长大阉公猪，随机分为2个处理组，分别饲养于（30±0.5）℃（高温组）和（22±0.5）℃（常温组）的环控舱内，单笼饲养，自由采食和饮水。环控舱内温度在21 d试验期内保持不变，湿度控制在(55±5)%，每天光照14 h，舱内持续均匀通风。试验期满屠宰，宰前12 h禁食，自由饮水。【结果】和常温组相比，高温组育肥猪胴体重和皮下脂肪厚有所降低，但并不显著（P＞0.10）；与常温组相比，高温组育肥猪背部皮下脂肪占胴体的比例无显著变化（P＞0.10），肾周脂肪占胴体的比例有提高趋势（+22.06%；P=0.07），背最长肌（LM）脂质含量有降低趋势（-22.39%；P=0.08），表明持续高温对猪不同部位脂肪沉积的影响存在差异。持续高温显著降低育肥猪背部皮下脂肪和肾周脂肪中苹果酸酶（ME）活性（P＜0.05）和脂肪酸合成酶（FAS）活性（P＜0.05），显著降低LM中乙酰辅酶A羧化酶（ACC）（P＜0.01）和FAS（P＜0.05）的含量，显著降低肝脏中FAS活性（P＜0.01）， FAS、ME 和 ACC 为脂肪酸从头合成过程中的关键酶，上述结果表明，持续高温抑制育肥猪不同组织脂肪酸的从头合成。持续高温对3个不同部位脂肪中激素敏感脂酶（HSL）的含量无显著影响（P＞0.10）。持续高温对育肥猪皮下脂肪中脂蛋白酯酶（LPL）含量无显著影响（P＞0.10），显著升高肾周脂肪中LPL含量（P=0.05），显著降低LM中LPL含量（P=0.05），持续高温对上述3个部位脂肪组织中LPL含量的影响规律与这3个部位脂肪沉积的影响规律相一致，表明持续高温可能通过调控LPL的含量，影响育肥猪不同部位脂肪的沉积。持续高温降低LM前部（P＜0.05）和后部（P＜0.01）的L（+）-β-羟脂酰CoA脱氢酶（HAD）的活性，HAD是脂肪酸β-氧化过程中的关键酶，上述结果表明，持续高温抑制育肥猪骨骼肌中脂肪酸的氧化供能。持续高温极显著升高LM中cAMP含量（P＜0.01），对肾周脂肪和背部皮下脂肪中cAMP含量无显著影响（P＞0.10）。持续高温显著升高血浆中非酯化脂肪酸（NEFA）的浓度（P＜0.05），有升高极低密度脂蛋白（VLDL）浓度的趋势（P=0.07），对总胆固醇(CHOL)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)和低密度脂蛋白胆固醇(LDL-C)浓度无显著影响(P＞0.10)。【结论】持续高温对育肥猪不同部位脂肪沉积的影响存在差异。环境高温可能通过影响LPL的含量，调控脂肪酸的摄入，影响育肥猪不同部位脂肪的沉积。环境高温抑制皮下脂肪、肾周脂肪、LM和肝脏组织中脂肪酸的从头合成，但同时也抑制骨骼肌组织中脂肪酸的β-氧化，这可能导致血浆中NEFA浓度升高，并在肝脏重新酯化、组装为VLDL，被脂肪组织重新摄入，但血浆中NEFA和VLDL升高的机制尚需进一步研究。
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