Effect of intermittent feeding on the development of disaccharidase activities in artificially reared rat pups

We investigated the effect of an intermittent feeding schedule on the devel opment of disaccharidase activities in the small intestine of artificially reared (AR) rat pups. Rat pups were fitted with an intragastric cannula at 5 days of age. A milk formula similar to the composition of rat milk was su pplied by intermittent gastric infusion over the following 15-19 days. The body weight gain and plasma corticosterone levels of the AR pups matched th ose of pups reared naturally by dams (MR pups). At 10, 15 and 19 days of ag e, the small intestine from the ligament of Treitz to the ileocecal junctio n was divided into three segments of equal length and enzyme activities wer e measured. in each. At the age of 10 and 15 days, sucrase and isomaltase a ctivities were undetectable in AR pups fed according to a controlled schedu le from the early postnatal period. These activities were first detected in the middle segment of the small intestine at 19 days of age in both AR and MR pups. Sucrase and isomaltase activities at; the age of 19 days were diu rnal in AR pups, but arrhythmic in MR pups. We conclude that artificial rea ring via the intermittent gastric infusion of a milk formula containing onl y lactose as the carbohydrate source did not prematurely increase intestina l sucrase and isomaltase activities. Diurnal changes started from the begin ning of development of these enzyme activities in AR pups. (C) 1998 Elsevie r Science Inc. All rights reserved.