Avian digestive tracts do NOT secrete which carbohydrase enzyme?
A Amylase
B Lactase
C Maltase
D Sucrase
The correct answer and explanation is:
The correct answer is B Lactase.
Avian species, like most birds, have digestive systems that are adapted to their specific dietary needs. In the context of carbohydrate digestion, birds primarily rely on enzymes like amylase, maltase, and sucrase to break down starches, sugars, and disaccharides. However, they do not typically secrete lactase.
- Amylase is secreted by the pancreas in birds, and it helps break down starches into simpler sugars like maltose and dextrins.
- Maltase breaks down maltose, a disaccharide produced from starch digestion, into two glucose molecules, aiding in the absorption of energy.
- Sucrase is responsible for breaking down sucrose into glucose and fructose, which are easily absorbed.
However, lactase, which is the enzyme responsible for breaking down lactose (the sugar found in milk), is not typically found in avian digestive systems. This is because birds generally do not consume milk in their natural diet. Lactose digestion is more common in mammals, especially those that nurse their young. The lack of lactase in birds is an adaptation to their diet, which rarely includes lactose.
Therefore, the absence of lactase secretion in birds is related to their lack of exposure to milk and lactose in the wild. This contrasts with mammals, who have evolved to produce lactase to process milk sugars. In avian species, the digestive system is optimized to handle other carbohydrate sources, but lactose is not one of them.