R. Zabielski et al., KINETICS OF PANCREATIC-JUICE SECRETION IN RELATION TO DUODENAL MIGRATING MYOELECTRIC COMPLEX IN PRERUMINANT AND RUMINANT CALVES FED TWICE-DAILY, British Journal of Nutrition, 78(3), 1997, pp. 427-442
Daily secretion of pancreatic juice, including postprandial responses
to food, was investigated in two groups of calves: preruminant (fed wi
th liquid food) and ruminant (fed with solid food). Male Friesian calv
es (1 week old and 6 weeks old) were surgically fitted with a pancreat
ic duct catheter, duodenal cannula and two duodenal electrodes. Contin
uous 24 h collections of pancreatic juice and myoelectrical recordings
were performed with minimal restraint and disturbance of animals. In
both groups of calves clear periodic fluctuations in pancreatic juice
secretion (volume, protein output and trypsin activity) coinciding wit
h duodenal migrating myoelectric complexes (MMC) were recorded. Secret
ion of juice per cycle and per day was greater in ruminant calves, but
the frequency and amplitude of cycles were lower in this group. There
were no differences between day and night-time preprandial pancreatic
cycles and duodenal MMC in preruminant calves, whilst in ruminant cal
ves, evening MMC were longer than morning MMC. The pancreatic cephalic
phase (increase of volume flow, protein output and trypsin activity d
uring and just after food intake) was significant only in preruminant
calves following morning feeding. Postprandial pancreatic cycles did n
ot differ from preprandial cycles, except the pancreatic cycle (juice
volume and trypsin activity) in which food was offered in preruminant
calves. No gastric or intestinal phase was observed in either group of
calves. In conclusion, biological cycles of the gastrointestinal trac
t are present in both preruminant and ruminant calves, and these cycle
s evolve along with the change from liquid to solid food.