Rott Katherine H, Caviedes-Vidal Enrique, Karasov William H
Department of Zoology, University of Wisconsin, 250 N Mills Street, Madison, WI 53706, USA.
Departamento de Bioquímica y Ciencias Biológicas, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis 5700, Argentina.
J Exp Biol. 2017 Aug 1;220(Pt 15):2733-2742. doi: 10.1242/jeb.157511. Epub 2017 May 11.
Nestling house sparrows near fledging age (12 days) were previously found to reversibly modulate the activity of their intestinal digestive enzymes in response to changes in diet composition. However, it is not known how quickly nestlings can adjust to new diets with different substrate compositions, nor is it known how early in life nestlings can modulate their enzyme activity in response to changes in diet. In the present study, 3-day-old nestlings were captured from the wild and fed and switched among contrasting diets - one high in protein and low in carbohydrate and another higher in carbohydrate and with lower, but adequate, protein - in order to determine (1) how quickly house sparrow nestlings could adjust to changes in diet composition, (2) how early in life nestlings could modulate their digestive enzyme activity in response to these changes and (3) which digestive enzymes could be modulated in house sparrow nestlings earlier in life. We found that house sparrow nestlings as young as 3 days post-hatch were capable of modulating their intestinal disaccharidase activity within 24 h of a change in diet composition, and nestlings gained the ability to modulate aminopeptidase-N by 6 or 7 days of age. To our knowledge, this is the first evidence of digestive enzyme modulation completed within 24 h of a change in diet in an avian species and the first study to show intestinal digestive enzyme modulation in response to changes in diet composition in any animal this early in development.
先前发现，接近离巢年龄（12日龄）的家麻雀雏鸟能够根据饮食组成的变化可逆地调节其肠道消化酶的活性。然而，尚不清楚雏鸟能多快适应具有不同底物组成的新饮食，也不清楚雏鸟在生命早期能多早根据饮食变化调节其酶活性。在本研究中，从野外捕获3日龄的雏鸟，用对比性饮食喂养并在不同饮食之间切换——一种高蛋白低碳水化合物，另一种高碳水化合物且蛋白质含量较低但充足——以确定：（1）家麻雀雏鸟能多快适应饮食组成的变化；（2）雏鸟在生命早期能多早根据这些变化调节其消化酶活性；（3）家麻雀雏鸟在生命早期哪些消化酶能被调节。我们发现，孵化后仅3日龄的家麻雀雏鸟能够在饮食组成改变后的24小时内调节其肠道双糖酶活性，并且雏鸟在6或7日龄时获得了调节氨肽酶-N的能力。据我们所知，这是鸟类在饮食改变后24小时内完成消化酶调节的首个证据，也是第一项表明在发育如此早期的任何动物中肠道消化酶能根据饮食组成变化进行调节的研究。
