USDA-ARS, Ames, IA 50011-3310, USA.
J Anim Sci. 2012 Feb;90(2):523-32. doi: 10.2527/jas.2010-3613. Epub 2011 Sep 16.
An experiment was conducted to determine the effects of feeding a moderate level of 2 different fiber sources on energy metabolites; mitochondrial biogenesis in the intestine, liver, and muscle; and the expression of some genes that regulate energy metabolism in intestine, liver, muscle, and adipose tissue. Female pigs (n = 36; BW = 15.0 ± 0.7 kg) were fed diets containing no added fiber, 12.5% sugar beet pulp (SBP), or 12.5% wheat bran (WB) for 24 d. Blood samples were collected on d 7 and 24 for cholesterol, glucose, NEFA, and triglyceride analyses. At completion of the experiment, ileum, colon, subcutaneous adipose, and LM samples were obtained from a subset (n = 6) of pigs fed each diet for analysis of tissue mitochondrial DNA (mtDNA) content and mRNA abundance by quantitative real-time reverse-transcription PCR. Glycogen and triglyceride content of liver and LM were determined, and colon content VFA was also determined. The addition of SBP or WB to the diet had no effect (P > 0.55) on ADG, ADFI, or G:F. Serum NEFA and triglycerides were increased (P < 0.05) in pigs fed SBP compared with pigs fed the control diet or WB on d 7, and NEFA remained increased (P < 0.05) on d 24 in pigs fed SBP. Dietary fiber had no effect (P > 0.24) on glycogen and triglyceride content of liver or LM, but colonic acetate concentrations were increased (P < 0.05) in pigs fed either SBP or WB. Pigs fed WB had an increased (P < 0.05) mtDNA content in ileum tissue and increased (P < 0.05) citrate synthase mRNA in colon tissue. In the liver, feeding either SBP or WB led to a decrease (P < 0.05) in mtDNA content, whereas feeding WB decreased (P < 0.05) mtDNA abundance in the LM, and feeding either SBP or WB decreased (P < 0.05) expression of citrate synthase mRNA. Quantitative reverse-transcription PCR revealed that feeding WB increased (P < 0.05) proliferating cell nuclear antigen mRNA abundance in the ileum and colon. Feeding WB increased (P < 0.05) mRNA abundance of a regulator of mitochondrial biogenesis, PPAR coactivator 1 α, in ileum tissue, and increased (P < 0.05) mRNA abundance of another mediator of mitochondrial biogensis, sirtuin 1, in colon tissue. Colonic mRNA expression of fasting-induced adipose factor was increased (P < 0.05) in pigs fed either SBP or WB, and adipose triglyceride lipase mRNA abundance was increased (P < 0.05) in adipose tissue of pigs fed SBP. These data indicate that increasing dietary fiber can increase the capacity of the intestine for oxidative metabolism and induce a repartitioning of energy metabolites depending on fiber source.
进行了一项实验，以确定喂养中等水平的两种不同纤维源对能量代谢物的影响；肠道、肝脏和肌肉中的线粒体生物发生；以及调节肠道、肝脏、肌肉和脂肪组织能量代谢的某些基因的表达。雌性猪（n = 36；BW = 15.0 ± 0.7 kg）饲喂不含添加纤维、12.5%糖蜜浆（SBP）或 12.5%麦麸（WB）的日粮 24 天。在第 7 天和第 24 天采集血液样本，用于胆固醇、葡萄糖、NEFA 和甘油三酯分析。在实验结束时，从饲喂每种日粮的猪中采集一小部分（n = 6）的回肠、结肠、皮下脂肪和 LM 样本，通过定量实时逆转录 PCR 分析组织线粒体 DNA（mtDNA）含量和 mRNA 丰度。测定肝脏和 LM 中的糖原和甘油三酯含量，并测定结肠内容物 VFA。在日粮中添加 SBP 或 WB 对 ADG、ADFI 或 G:F 没有影响（P > 0.55）。与对照组或 WB 相比，饲喂 SBP 的猪在第 7 天血清 NEFA 和甘油三酯增加（P < 0.05），并且在第 24 天，饲喂 SBP 的猪的 NEFA 仍在增加（P < 0.05）。膳食纤维对肝脏或 LM 中的糖原和甘油三酯含量没有影响（P > 0.24），但饲喂 SBP 或 WB 的猪的结肠乙酸盐浓度增加（P < 0.05）。饲喂 WB 的猪回肠组织 mtDNA 含量增加（P < 0.05），结肠组织柠檬酸合酶 mRNA 增加（P < 0.05）。在肝脏中，饲喂 SBP 或 WB 导致 mtDNA 含量降低（P < 0.05），而饲喂 WB 降低了 LM 中的 mtDNA 丰度（P < 0.05），并且饲喂 SBP 或 WB 降低了柠檬酸合酶 mRNA 的表达（P < 0.05）。定量逆转录 PCR 显示，饲喂 WB 增加了回肠和结肠中增殖细胞核抗原 mRNA 的丰度（P < 0.05）。饲喂 WB 增加了回肠组织中线粒体生物发生调节剂过氧化物酶体增殖物激活受体共激活因子 1α 的 mRNA 丰度（P < 0.05），并增加了结肠组织中线粒体生物发生的另一种调节剂 Sirtuin 1 的 mRNA 丰度（P < 0.05）。饲喂 SBP 或 WB 的猪结肠中禁食诱导脂肪因子的 mRNA 表达增加（P < 0.05），并且饲喂 SBP 的猪的脂肪组织中脂肪甘油三酯脂肪酶 mRNA 丰度增加（P < 0.05）。这些数据表明，增加膳食纤维可以增加肠道的氧化代谢能力，并根据纤维源重新分配能量代谢物。
