Effect of an abrupt switch from a milk-based to a fibre-based diet on gastric emptying rates in pigs: difference between origins of fibre.

A characteristic dietary feature at weaning is a switch from a milk-based to plant-based diet, i.e. from a non-fibrous to a fibrous diet. The present study aimed to evaluate the effects of such an abrupt dietary switch on gastric emptying rate in pigs maintained on a milk substitute after weaning. Eighteen piglets were kept on a milk substitute for 5 weeks after weaning and were then switched to wheat-based or barley-based diets or kept on the milk substitute (six piglets per group). All piglets were fasted for 1 d before the switch and daily food intake was then increased linearly to reach initial values within 3 d. The gastric emptying rate was measured by gamma-scintigraphy before and after the switch. Corpo-antral peristalsis was also evaluated by the use of high-frequency scintigraphic frames. The gastric emptying rate of the wheat-based diet was accelerated on days 1 to 3 after the switch, but was similar to that in the milk-substitute group thereafter. This acceleration was concomitant with an enhanced frequency of corpo-antral waves on days 2 and 3. Conversely, the gastric emptying rate of the barley-based diet tended to be enhanced on day 2, but was delayed on days 4 and 5, without any change in frequency of corpo-antral waves. We conclude that a switch from a non-fibrous to a fibrous diet alters the gastric emptying rate differently depending on the type of dietary fibre.