Effects of di- and monosaccharides on the proximo-distal gradient of carbohydrase activity of chick small intestine

Development of disaccharidase activity in the small intestine of broiler chickens

1. The changes in disaccharidase activity in the small intestine of broiler chickens were investigated in isolated enterocytes on d 18 of embryonic development and d 1, 7, 21, 35 and 56 after hatching. 2. The specific activities of maltase, lactase and trehalase were greatest on d 18 of embryonic development. After hatching, maltase specific activity gradually decreased until d 18. 3. After d 7 postnatally only traces of lactase and trehalase activity were found in the enterocytes. 4. Significant sucrase activity was found on d 18 of embryonic development and the activity of this enzyme increased 2-fold after hatch and remained generally constant up to d 35, after which the enzyme specific activity declined.

Intestinal disaccharidases of young turkeys: temporal development and influence of diet composition

An experiment was done to determine maltase, sucrase, isomaltase, and trehalase activities in mucosa of different segments of small intestines of young turkeys as influenced by age and diet. Two-day-old poults were fed diets containing no added fat [44.6% starch, 2.2% ether extract by weight (HC)], 10% tallow (T), or 10% corn oil [(CO) 29.0% starch, 10.9% ether extract]. Diets HC, T, and CO were calculated to contain 2,705, 3,083, and 3,196 kcal ME/kg, respectively, and constant protein, TSAA, and lysine:ME ratios were maintained. Appreciable maltase and isomaltase specific activities (micromoles of substrate hydrolyzed per milligram protein per hour) were observed in 2-day-old poults, and activities of these enzymes increased in poults fed the HC diet through 7 and 14 days, respectively. At 2 days, specific activity of sucrase was low, and trehalase activity was not detected. Sucrase activity increased steadily through 28 days of age in poults fed the HC diet. Trehalase activity was detected at 7 days of age and reached a maximum by Day 21 after hatch. By Day 28, trehalase activity had disappeared from all segments except for the proximal jejunum. In 28-day-old poults fed the HC diet, specific activities of all disaccharidases were greatest in the jejunal segments; i.e., 21, 1.06, 7.24, and .034 mumol/mg protein/h for maltase, sucrase, isomaltase, and trehalase, respectively, in the proximal jejunum. Poults fed the T or CO diets had significantly lower disaccharidase activities than did those fed the HC diet, beginning at 7 days of age. Changes in specific activities of disaccharidases as related to age or diet or both were not always parallel, suggesting that each enzyme may be regulated by or affected by diet in a partly independent way.

The role of the duodenum in adaptive changes in sucrose digestion in the small intestine of chicks

In two experimental series in situ applying perfusion technique, and in vitro, the role of the duodenum in adaptation of sucrose digestion was investigated in the proximal, medial and distal parts of the chick small intestine. No adaptive changes occurred in hydrolysis and carbohydrate transport if the pancreo-duodenal complex was isolated from the lower parts. It is suggested that on feeding with sucrose, factors arise in the duodenal mucosa causing adaptive changes in sucrase activity of the small intestine.

Adaptation of the activity of membrane carbohydrases of chick small intestine to various carbohydrates

Adaptation changes in membrane carbohydrases and those localized in the apical glycocalyx of enterocytes have been studied in chicks under the impact of carbohydrates. The investigated enzymes were not equally adapted to the carbohydrates of various degrees of polymerization. The response character of membrane carbohydrases depends on proximo-distal localization of enzymes in the small intestine and it is not specific to carbohydrates.