title: Transcriptome Analysis Reveals Regulation of Gene Expression for Lipid Catabolism in Young Broilers by Butyrate Glycerides.
abstract: OBJECTIVE
  Butyrate has been shown to potently regulate energy expenditure and lipid metabolism in animals, yet the underlying mechanisms remain to be fully understood. The aim of this study was to investigate the molecular mechanisms of butyrate (in the form of butyrate glycerides, BG)-induced lipid metabolism at the level of gene expression in the jejunum and liver of broilers.
  
  
  RESULTS
  Two animal experiments were included in this study. In Experiment 1, two hundred and forty male broiler chickens were equally allocated into two groups: 1) basal diet (BD), 2) BG diets (BD + BG). Growth performance was compared between treatments for the 41-day trial. In Experiment 2, forty male broiler chickens were equally allocated into two groups. The general experimental design, group and management were the same as described in Experiment 1 except for reduced bird numbers and 21-day duration of the trial. Growth performance, abdominal fat deposition, serum lipid profiles as well as serum and tissue concentrations of key enzymes involved in lipid metabolism were compared between treatments. RNA-seq was employed to identify both differentially expressed genes (DEGs) and treatment specifically expressed genes (TSEGs). Functional clustering of DEGs and TSEGs and signaling pathways associated with lipid metabolism were identified using Ingenuity Pathways Analysis (IPA) and DAVID Bioinformatics Resources 6.7 (DAVID-BR). Quantitative PCR (qPCR) assays were subsequently conducted to further examine the expression of genes in the peroxisome proliferator-activated receptors (PPAR) signaling pathway identified by DAVID-BR. Dietary BG intervention significantly reduced abdominal fat ratio (abdominal fat weight/final body weight) in broilers. The decreased fat deposition in BG-fed chickens was in accordance with serum lipid profiles as well as the level of lipid metabolism-related enzymes in the serum, abdominal adipose, jejunum and liver. RNA-seq analysis indicated that dietary BG intervention induced 79 and 205 characterized DEGs in the jejunum and liver, respectively. In addition, 255 and 165 TSEGs were detected in the liver and jejunum of BG-fed group, while 162 and 211 TSEGs genes were observed in the liver and jejunum of BD-fed birds, respectively. Bioinformatic analysis with both IPA and DAVID-BR further revealed a significant enrichment of DEGs and TSEGs in the biological processes for reducing the synthesis, storage, transportation and secretion of lipids in the jejunum, while those in the liver were for enhancing the oxidation of ingested lipids and fatty acids. In particular, transcriptional regulators of THRSP and EGR-1 as well as several DEGs involved in the PPAR-α signaling pathway were significantly induced by dietary BG intervention for lipid catabolism.
  
  
  CONCLUSIONS
  Our results demonstrate that BG reduces body fat deposition via regulation of gene expression, which is involved in the biological events relating to the reduction of synthesis, storage, transportation and secretion, and improvement of oxidation of lipids and fatty acids.
authors: Guelph Research and Development Centre, Agriculture and Agri-Food Canada, Guelph, Ontario, Canada.
authors: Fugui
authors: F
authors: Yin
authors: Guelph Research and Development Centre, Agriculture and Agri-Food Canada, Guelph, Ontario, Canada.
authors: Hai
authors: H
authors: Yu
authors: Guelph Research and Development Centre, Agriculture and Agri-Food Canada, Guelph, Ontario, Canada.
authors: Dion
authors: D
authors: Lepp
authors: Next Generation Sequencing Platforms, Clinical Genomics Centre, the UHN/MSH Gene Profiling Facility, Toronto, Ontario, Canada.
authors: Xuejiang
authors: X
authors: Shi
authors: Guelph Research and Development Centre, Agriculture and Agri-Food Canada, Guelph, Ontario, Canada.
authors: Xiaojian
authors: X
authors: Yang
authors: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi, China.
authors: Jielun
authors: J
authors: Hu
authors: Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada.
authors: Steve
authors: S
authors: Leeson
authors: Department of Animal Science, University of Manitoba, Winnipeg, Manitoba, Canada.
authors: Chengbo
authors: C
authors: Yang
authors: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi, China.
authors: Shaoping
authors: S
authors: Nie
authors: Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan, Hubei, China.
authors: Yongqing
authors: Y
authors: Hou
authors: Guelph Research and Development Centre, Agriculture and Agri-Food Canada, Guelph, Ontario, Canada.
authors: Joshua
authors: J
authors: Gong
mesh_terms: D000103:Acetyl-CoA Carboxylase / Q000378:metabolism; D000273:Adipose Tissue / Q000187:drug effects; D000821:Animal Feed; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D020148:Butyric Acid / Q000737:chemistry / Q000494:pharmacology*; D002645:Chickens / Q000254:growth & development*; D054890:Fatty Acid Synthase, Type I / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D005989:Glycerides / Q000494:pharmacology; D050356:Lipid Metabolism / Q000187:drug effects* / Q000235:genetics*; D008297:Male; D047493:PPAR alpha / Q000235:genetics / Q000378:metabolism; D014280:Triglycerides / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D001786:Blood Glucose; D005989:Glycerides; D047493:PPAR alpha; D014280:Triglycerides; D020148:Butyric Acid; C063895:1-butyrylglycerol; D054890:Fatty Acid Synthase, Type I; D000103:Acetyl-CoA Carboxylase