Dietary phospholipid alters biliary lipid composition in formula-fed piglets

Plasma cholesterol, arachidonic acid (AA, 20:4n-6), and docosahexaenoic aci d (DHA, 22:6n-3) are higher in breast-fed infants than in infants fed formu la without cholesterol, AA, or DHA. This study investigated differences in plasma, hepatic, and bile lipids and phospholipid fatty acids, and expressi on of hepatic proteins involved in sterol metabolism that result from feedi ng formula with cholesterol with egg phospholipid to provide AA and DHA. Fo r this study, three groups of piglets were evaluated: piglets fed formula w ith 0.65 mmol/L cholesterol, the same formula with 0.8% AA and 0.2% DHA fro m egg phospholipid, and piglets fed sow milk. Piglets fed the formula with phospholipid AA and DHA had higher plasma high density lipoprotein, but not apoprotein (apo) B cholesterol or triglyceride; higher bile acid and phosp holipid concentrations in bile; and higher liver and bile phospholipid AA a nd DHA than piglets fed formula without AA and DHA (P < 0.05). Hydroxy meth ylglutaryl (HMG)-CoA reductase and 7-alpha hydroxylase, the rate-limiting e nzymes of cholesterol and bile acid synthesis, respectively, and low densit y lipoprotein receptor mRNA levels were not different between piglets fed f ormula without and with phospholipid AA and DHA, but HMG-CoA reductase and 7 alpha-hydroxylase mRNA were higher, and plasma apo B containing lipoprote in cholesterol was lower in all piglets fed formula than in piglets fed mil k. These studies show that supplementing formula with AA and DHA from egg p hospholipid alters bile metabolism by increasing the bile AA and DHA, and b ile acid and phospholipid.