title: Dietary Egg Yolk Supplementation Improves Low-Protein-Diet-Induced Fatty Liver in Rats.
abstract: Egg yolk is an important source of nutrients and contains different bioactive substances. In the present study, we studied the benefits of egg yolk in preventing low-protein-diet-induced fatty liver in rats. Rats were fed the following diets, which were based on the AIN-76 formula, for 2 wk: an adequate-protein diet containing 20% casein (C), a low-protein diet containing 5% casein (LP-C), a low-protein diet supplemented with 12.5% egg yolk (LP-EY), and a low-protein diet supplemented with 4.1% egg yolk oil (LP-EYO). The low-protein diets were adjusted to contain 4.13% protein and 4.7% lipids. The LP-C diet resulted in a greater increase in the liver trigriceride (TG) and the vacuolation and a greater decrease in the serum TG and free fatty acid (FFA) than did the C diet. These deviations in the serum and liver TG, serum FFA levels and the liver histopathology were corrected in rats fed the LP-EY diet but not in those fed the LP-EYO diet. Compared to rats fed the LP-C diet, although the activities of lipogenesis-related enzymes (fatty acid synthase, glucose-6-phosphate dehydrogenase, and malic enzyme) decreased in rats fed both of the LP-EY and LP-EYO diets, the level of the microsomal TG transfer protein (MTP) increased only in rats fed the LP-EY diet. Collectively, these results suggest that dietary egg yolk supplementation decreases the LP diet-induced accumulation of TG in the liver by increasing transport of TG in the liver, and egg yolk oil alone is not sufficient enough to bring about these benefits.
authors.affiliation: Laboratory of Nutrition Chemistry, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Erami
authors.forename: Yasutake
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Sayaka
authors.initials: S
authors.lastname: Kawamura
authors.forename: Motonori
authors.initials: M
authors.lastname: Miyago
authors.forename: Ai
authors.initials: A
authors.lastname: Sawazaki
authors.forename: Katsumi
authors.initials: K
authors.lastname: Imaizumi
authors.forename: Masao
authors.initials: M
authors.lastname: Sato
mesh_terms: D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D002352:Carrier Proteins / Q000378:metabolism; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D018753:Diet, Protein-Restricted / Q000009:adverse effects*; D004195:Disease Models, Animal; D004530:Egg Yolk; D064429:Fatty Acid Synthases / Q000378:metabolism; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005234:Fatty Liver / Q000178:diet therapy* / Q000209:etiology; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D050155:Lipogenesis; D008099:Liver / Q000378:metabolism; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D014280:Triglycerides / Q000097:blood
chemical_list: D002352:Carrier Proteins; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D005230:Fatty Acids, Nonesterified; D014280:Triglycerides; C106092:microsomal triglyceride transfer protein; D005954:Glucosephosphate Dehydrogenase; D064429:Fatty Acid Synthases; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase