Hypolipidemic effect of dietary water-soluble protein extract from chicken: impact on genes regulating hepatic lipid and bile acid metabolism

Eur J Nutr. 2015 Mar;54(2):193-204. doi: 10.1007/s00394-014-0700-5. Epub 2014 Apr 23.


Background: Amount and type of dietary protein have been shown to influence blood lipids. The present study aimed to evaluate the effects of a water-soluble fraction of chicken protein (CP) on plasma and hepatic lipid metabolism in normolipidemic rats.

Methods: Male Wistar rats were fed either a control diet with 20 % w/w casein as the protein source, or an experimental diet where casein was replaced with CP at 6, 14, or 20 % w/w for 4 weeks.

Results: Rats fed CP had markedly reduced levels of triacylglycerols (TAG) and cholesterol in both plasma and liver, accompanied by stimulated hepatic mitochondrial fatty acid oxidation and carnitine palmitoyltransferase 2 activity in the 20 % CP group compared to the control group. In addition, reduced activities and gene expression of hepatic enzymes involved in lipogenesis were observed. The gene expression of sterol regulatory element-binding transcription factor 1 was reduced in the 20 % CP-fed rats, whereas gene expression of peroxisome proliferator-activated receptor alpha was increased. Moreover, 6, 14, and 20 % CP-fed rats had significantly increased free carnitine and acylcarnitine plasma levels compared to control rats. The plasma methionine/glycine and lysine/arginine ratios were reduced in 20 % CP-treated rats. The mRNA level of ATP-binding cassette 4 was increased in the 20 % CP group, accompanied by the increased level of plasma bile acids.

Conclusions: The present data suggest that the hypotriglyceridemic property of a water-soluble fraction of CP is primarily due to effects on TAG synthesis and mitochondrial fatty acid oxidation. The cholesterol-lowering effect by CP may be linked to increased bile acid formation.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / analysis
  • Animals
  • Bile Acids and Salts / metabolism*
  • Carnitine O-Palmitoyltransferase / metabolism
  • Caseins / administration & dosage
  • Chickens*
  • Cholesterol / blood
  • Cholesterol / metabolism
  • Dietary Proteins / administration & dosage
  • Dietary Proteins / chemistry
  • Dietary Proteins / therapeutic use*
  • Dietary Supplements* / analysis
  • Gene Expression Regulation, Enzymologic
  • Hyperlipidemias / blood
  • Hyperlipidemias / metabolism
  • Hyperlipidemias / prevention & control
  • Hypolipidemic Agents / administration & dosage
  • Hypolipidemic Agents / chemistry
  • Hypolipidemic Agents / therapeutic use*
  • Lipid Metabolism*
  • Liver / enzymology
  • Liver / metabolism*
  • Male
  • Meat Products / analysis
  • Mitochondria, Liver / enzymology
  • Mitochondria, Liver / metabolism
  • Random Allocation
  • Rats, Sprague-Dawley
  • Solubility
  • Triglycerides / blood
  • Triglycerides / metabolism


  • Amino Acids
  • Bile Acids and Salts
  • Caseins
  • Dietary Proteins
  • Hypolipidemic Agents
  • Triglycerides
  • Cholesterol
  • Carnitine O-Palmitoyltransferase