Impact of dietary protein on lipid metabolism in hamsters is source-dependent and associated with changes in hepatic gene expression.
This study tested the hypothesis that protein source is a factor determining the impact of the diet on lipid metabolism in hamsters. Twenty-eight hamsters of similar body weight were assigned for a period of 8 weeks to one of the following four diets (seven per group) containing either 20 % (w/w) casein (CAS), beef protein (BF), wheat gluten (WG) or soya protein (SOY). The fat composition of the diet was the same (15.5 % w/w) in all groups and provided SFA, MUFA and PUFA representative of the average Canadian diet. After an overnight fast, blood and liver were collected for the measurement of serum lipids, fatty acid composition of liver phospholipids and mRNA levels of selected genes involved in lipid metabolism. WG resulted in lower total cholesterol, HDL-cholesterol and non-HDL-cholesterol but, along with SOY, in higher mRNA levels of cholesterol 7 alpha-hydroxylase and LDL receptor. Furthermore, both WG and SOY resulted in lower 18 : 3n-3, 20 : 4n-6, total n-6 PUFA, 18 : 1n-9 and total MUFA, but higher 22 : 6n-3, total n-3 PUFA, 22 : 6n-3/18 : 3n-3 and 22 : 5n-3/18 : 3n-3 ratios in liver phospholipids, and higher hepatic Delta6-desaturase mRNA levels. These results show that the impact of dietary protein on lipid metabolism is source-dependent and associated with changes in mRNA abundances of key hepatic enzymes and receptors.
Aziz
Alfred
A
Nutrition Research Division, Food Directorate, Health Products and Food Branch, Health Canada, PL 2203E, 251 Sir Frederick Banting Driveway, Ottawa K1A 0K9, ON, Canada.
Xiao
Chao Wu
CW
Cockell
Kevin A
KA
Sarwar Gilani
G
G
Cruz-Hernandez
Cristina
C
Nimal Ratnayake
W M
WM
D000818:Animals; D002364:Caseins / Q000008:administration & dosage; D002417:Cattle; D002784:Cholesterol / Q000097:blood; D002790:Cholesterol 7-alpha-Hydroxylase / Q000235:genetics; D008076:Cholesterol, HDL / Q000097:blood; D006224:Cricetinae; D004044:Dietary Proteins / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000032:analysis / Q000378:metabolism; D015870:Gene Expression; D005983:Glutens / Q000008:administration & dosage; D050356:Lipid Metabolism / Q000235:genetics*; D008055:Lipids / Q000097:blood; D008099:Liver / Q000201:enzymology*; D008297:Male; D008460:Meat; D008647:Mesocricetus; D023421:Models, Animal; D010743:Phospholipids / Q000737:chemistry / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D011897:Random Allocation; D011973:Receptors, LDL / Q000235:genetics; D030262:Soybean Proteins / Q000008:administration & dosage
D002364:Caseins; D008076:Cholesterol, HDL; D004044:Dietary Proteins; D005231:Fatty Acids, Unsaturated; D008055:Lipids; D010743:Phospholipids; D012333:RNA, Messenger; D011973:Receptors, LDL; D030262:Soybean Proteins; D005983:Glutens; D002784:Cholesterol; D002790:Cholesterol 7-alpha-Hydroxylase