Thus, vitamin B intake for C S and E S treatments was and mg, respectively.On experimental days, the animals were placed in metabolic cages and fed one of the experimental meals.Blood samples were collected simultaneously from the two catheters every min for the rst hpostfeeding, and every hour for the following h.Packed cell volume was measured in duplicate on fresh blood by microcentrifugation.Plasma was collected after centrifugation at gfor min at C and frozen at C for further analysis.Signals from the ow probes were lost for the last period for one pig. For these two pigs, the calculations of PDV uxes for these periods were done using the average plasma ow at each <a href="http://www.targetmol.com/compound/Dyclonine-hydrochloride"></a>
sampling time recorded during the previous periods.The estimated values for these periods were not included in statistical analysis of blood and plasma ows.Statistical analyses of blood and plasma ows, arterial concentrations, venoarterial difference and PDV ux of vitamin B were conducted on postprandial values that were averaged across the hpost meal.As time intervals between the blood samples were unequal, the average net ux of vitamin B across PDV during the hpost meal was calculated as the summation of PDV net ux at each time point multiplied by the interval of time between the two consecutive samples divided by min.A positive net ux indicates a release of a nutrient from PDV, whereas a negative ux indicates an uptake.All variables were analysed using the MIXED procedure of SAS according to a splitplot design with vitamin B concentration and period as the main plots, treatment and the vitamin B concentration treatment interaction as the subplots and the vitamin B concentration period and treatment period within vitamin B concentration interactions as the random effects.Average portoarterial difference and PDV ux of vitamin B during the hpost meal were not affected by vitamin B concentration. Average portoarterial difference in vitamin B during the hpost meal was higher than those fed cyanocobalamin.However, there was no difference milk or between pasteurised and microltrated different when the pigs were fed the unsupplemented milk.A rst one, used as a reference method, measured wholebody deposition of vitamin B after several days of dietary supplementation, whereas the second method measured the net ux of vitamin B across PDV following a single meal supplemented with cyanocobalamin.The second method requires sophisticated surgical preparation, but it has the great advantage of measuring the bioavailability of different concentrations or sources of vitamin B within the same animal.Although estimates of bioavailability varied according to the two methods, both showed an inverse relationship between dietary concentrations of vitamin B and bioavailability of this vitamin as reported previously for human subjects. Those results are in accordance with the observations that the mechanisms of absorption of vitamin B in pigs supporting that the pig is an appropriate model to estimate vitamin B availability for human subjects.In contrast, in the present study, the actual mean net PDV uxes of vitamin B after ingestion of meals supplemented with and mg of cyanocobalamin were not different from. It can be hypothesised that a milk component, which survived the technological process for production of vitaminfree casein, improves intestinal absorption of vitamin B.