Development of Bile Secretory Function in the Neonatal Guinea Pig

Background: The type of feeding can differently influence bile acid ontogeny during the period of physiologic cholestasis that characterizes early human development. Aim: To investigate the effects of feeding from birth, conventional or partially protein hydrolyzed cow’s milk formulas were compared with breast milk regarding bile acid concentration and the composition of gallbladder bile in newborn guinea pigs. Methods: Forty newborn guinea pigs were allocated to one of three different feeding regimens: breast milk (n = 14), intact protein formula (n = 13) and partially protein hydrolyzed formula (n = 13). After 8 days, one third of the pups from each group was sacrificed; another third was sacrificed on the 14th day and the remainder on the 20th day of life. Bile acids in gallbladder bile were analyzed by gas chromatography/mass spectrometry and HPLC. Results: During the first 2 weeks of life, weight gain was significantly higher in breast-fed than in artificially fed pups. An age-related increase in total biliary bile acid concentrations was evident for breast-fed and hydrolyzed formula-fed animals, but not for those fed intact protein formula. Breast-fed animals had the highest total biliary bile acid concentrations on day 20 of life, with significant increases in chenodeoxycholic and 7-oxo-lithocholic acid concentrations, which were absent in the other two groups. Concentrations of 7-oxo-lithocholic acid on day 8 were significantly higher in animals fed intact protein formula compared with breast-fed and partially protein hydrolyzed formula-fed animals. Conclusions: In newborn guinea pigs, breast feeding is associated with a marked increase in biliary bile acid concentrations, which was not observed in artificially fed animals. The higher biliary bile acid concentrations and better weight gain in our breast-fed animals may reflect a greater feed efficiency associated with natural feeding. Biliary bile acid composition on day 8 suggests more rapid intestinal bacterial bile acid biotransformation in animals fed intact protein formula compared to other feeding regimens.

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Influence of Breast Feeding, and Adapted and Hydrolyzed Formulas on Biliary Bile Acids in Newborn Guinea Pigs

Colombo¹,

Setchell

Crosignani

et al. 2003

“…These conditions are present in the young guinea pig as guinea pig milk contains more cholesterol and fat than guinea pig chow. Also, newborn guinea pigs experience cholestasis [24], which may addi tionally lead to down-regulation of the recep tor, as intravenous infusion of bile acids in dogs decreases hepatic LDL receptor binding [25].…”

Section: Discussionmentioning

confidence: 99%

A Comparative Study of Hepatic HMG CoA Reductase Activity and LDL Receptor Relative Mass in Suckling and Adult Guinea Pigs

Hamilton

Auestad²,

Innis³

1994

The reason why plasma cholesterol levels increase soon after birth is unknown but may be related to change rates of cholesterol synthesis and/or expression of LDL receptors. Plasma cholesterol levels, along with hepatic HMG CoA reductase activity, the rate-limiting enzyme of cholesterol synthesis, and hepatic LDL receptor relative mass were measured in suckling (1,4 and 8 days of age) and adult guinea pigs. Plasma cholesterol was measured by an enzymatic assay, HMG CoA reductase activity was determined using a radiolabelled substrate and LDL receptor-relative mass was measured by ligand blotting with gold-labelled rabbit βVLDL. Among the young animals, HMG CoA reductase activity and plasma cholesterol levels increased between 1 and 4 days of age. The LDL receptor mass did not change in the first 8 days after birth, but was 2-fold higher in adult than suckling animals. Hepatic HMG CoA reductase activity was also higher in the adult animals. Increased hepatic HMG CoA reductase and low LDL receptor mass may contribute to the elevation in plasma LDL cholesterol levels in the 4-day-old guinea pig.

“…Maturation of these critical functions of the liver is vital for the postnatal survival of the species. In vivo/vitro studies in rats [1], guinea pigs [2], rabbits [3] and puppies [4] have shown a decreased bile acid synthesis, bile pool size, uptake of bile acids, bile flow and decreased absorption of bile acids from the intestine during the newborn period compared to the adult peri ods. Because there is considerable variation among the species in these functions, extrapo lation of data obtained from animal studies to humans would be difficult.…”

Section: Introductionmentioning

confidence: 99%

Bile Flow and Composition in Preterm, Term and Infant Baboons

Bhat

Chari²,

Meller³

et al. 1997

We studied the maturational changes in bile composition, bile flow and choleretic effects of sodium taurocholate and secretin in preterm (160 ± 2 days, n = 4, group I), term (184 ± 2 days, n = 4, group II), 7-day postnatal age (n = 5, group III) and 60-day-old (n = 5, group IV) baboons. The canalicular bile flow was determined by ¹⁴C-erythritol clearance. Results: Gall bladder volume increased from group I to group III (0.08 ± 0.06 to 1.06 ± 0.93 ml). Bile flow increased significantly from group I to IV (0.13 ± 0.05 to 0.34 ± 0.07 μl/min/g liver weight, p < 0.05). This was associated with significant increases in total bile acid excretion (16 ± 3.6 to 31 ± 2.5 m.Eq/l, p < 0.05). The composition of bile also showed maturational changes with increasing postnatal age. Sodium taurocholate and secretin increased the bile flow significantly in all groups. Conclusion: Data from these studies clearly demonstrate that the bile flow and bile acid excretion is immature in preterm and term baboons when compared to 7- and 60-day-old baboons. The present studies also suggest that baboons can be used as a model to study the postnatal maturation of hepatic excretory function.