Fish protein hydrolysate elevates plasma bile acids and reduces visceral adipose tissue mass in rats.
Conjugation of bile acids (BAs) to the amino acids taurine or glycine increases their solubility and promotes liver BA secretion. Supplementing diets with taurine or glycine modulates BA metabolism and enhances fecal BA excretion in rats. However, it is still unclear whether dietary proteins varying in taurine and glycine contents alter BA metabolism, and thereby modulate the recently discovered systemic effects of BAs. Here we show that rats fed a diet containing saithe fish protein hydrolysate (saithe FPH), rich in taurine and glycine, for 26 days had markedly elevated fasting plasma BA levels relative to rats fed soy protein or casein. Concomitantly, the saithe FPH fed rats had reduced liver lipids and fasting plasma TAG levels. Furthermore, visceral adipose tissue mass was reduced and expression of genes involved in fatty acid oxidation and energy expenditure was induced in perirenal/retroperitoneal adipose tissues of rats fed saithe FPH. Our results provide the first evidence that dietary protein sources with different amino acid compositions can modulate the level of plasma bile acids and our data suggest potential novel mechanisms by which dietary protein sources can affect energy metabolism.
National Institute of Nutrition and Seafood Research, Box 2029 Nordnes, N-5817 Bergen, Norway. bjorn.liaset@nifes.no
Bjørn
B
Liaset
Lise
L
Madsen
Qin
Q
Hao
Gabriel
G
Criales
Gunnar
G
Mellgren
Hanns-Ulrich
HU
Marschall
Philip
P
Hallenborg
Marit
M
Espe
Livar
L
Frøyland
Karsten
K
Kristiansen
D000818:Animals; D001647:Bile Acids and Salts / Q000097:blood*; D004044:Dietary Proteins / Q000008:administration & dosage; D004734:Energy Metabolism / Q000187:drug effects; D005399:Fishes; D005998:Glycine / Q000008:administration & dosage; D050152:Intra-Abdominal Fat / Q000378:metabolism*; D008055:Lipids / Q000032:analysis; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics / Q000378:metabolism; D011492:Protein Hydrolysates / Q000008:administration & dosage*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013654:Taurine / Q000008:administration & dosage; D014280:Triglycerides / Q000097:blood
D001647:Bile Acids and Salts; D004044:Dietary Proteins; D005998:Glycine; D008055:Lipids; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D011492:Protein Hydrolysates; D012333:RNA, Messenger; D013654:Taurine; D014280:Triglycerides; C489542:Abcc4 protein, rat