Milk diet but not quercetin intake affects postprandial glucose metabolism in neonatal calves
The hypothesis was tested that the flavonoid quercetin, which exerts effects on glucose metabolism in several species, influences postprandial glucose uptake in neonatal calves and that this effect depends on milk diet. Twenty-seven new-born male German Holstein calves were randomly assigned to two feeding groups receiving same amounts of either colostrum (C; n=14) or a milk-based formula (F; n=13) with same nutrient density as C, but no biologically active factors during the first two d of life. From d 3 to d 7, all calves were fed milk replacer at 12% of BW (150 g powder/L). From d 2 on, groups were subdivided each into a treatment group receiving 150 µmol/(kg BW × d) quercetin as quercetin aglycon with milk and a control group without additional quercetin. On d 7, calves were tube-fed their morning meal (4% of BW) mixed with 10 mg/kg BW [13C6]-glucose and the daily quercetin dose. Immediately afterwards, an intravenous bolus dose of [6.6-2H2]-glucose (5 mg/kg BW) was applied through a jugular vein catheter. Blood samples were taken to measure plasma 13C and 2H glucose enrichments and to calculate rates of glucose appearance (Rai.v. resp. Raoral) and fractional first pass splanchnic uptake (FPU) of glucose. Additional blood samples were taken to determine plasma concentrations of glucose, insulin, glucagon, noradrenaline and adrenaline. Data were analysed either by General Linear Model or by Mixed Model of SAS with feeding, quercetin, and time as fixed effects. Plasma concentrations of glucose, insulin, glucagon, and adrenaline were greater (P < 0.05) in C- than in F-fed calves. Recovery of decreased adrenaline to basal concentrations was faster (P < 0.05) when quercetin was fed. Glucose FPU and Raoral were greater (P < 0.05) in F- than in C-fed calves, but were not affected by quercetin. Results underline the importance of colostrum feeding during the first days of life on postprandial glucose metabolism and indicate that quercetin does not have a major effect on glucose metabolism neither in C- nor in F-fed neonatal calves.
Keywords: quercetin, glucose first-pass uptake, calf