Development of specific activity of amylolytic and proteolytic enzymes in duodenum and jejunum of the small intestinal tract of meat-type ducks during 1-42 days of age

Abstract

This experiment was conducted to elucidate the pattern of amylolytic and proteolytic digestive enzyme activities in meat-type ducks during 1-42 days of age. Twenty-eight male meat type ducks (Cherry Valley strain) were used, and diets based on corn-soybean meal were offered ad lib throughout the experimental period. At duodenal and jejunal segments, the specific activity (SA) of amylolytic (amylase) and proteolytic (trypsin, chymotrypsin and total proteases) enzymes were determined at 1, 7, 14, 21, 28, 35 and 42 days of age. Maximal or nearly maximal SA of all enzymes at first day after hatch (1 day of age) and the activity declined on 7 day of age was found (P<0.05). After 7 days of age, all enzymes tended to reach a nadir at day 14 or day 21, then the SA were significantly increased from 21 to 42 days of age (P<0.05). Therefore, the pattern of SA of all enzymes at duodenal and jejunal segments were changed in a cubic trend (P< 0.01) with age. In ducks, it is indicated that the embryonic enzyme reserve may be a reason of high SA of amylolytic and proteolytic enzymes at 1 day of age, then the SA are activated again after 21 days of age by intestinal development processes and/or increasing amount of feed intake.