Question

For a cow (ruminant)- Alfalfa hay and horse- Barley.
For the animal - feed ingredient combination listed. Fully describe each of the following.
Absorption of each nutrient. Be sure to describe the absorption of different minerals, vitamins, types of carbohydrates, types of amino acids, and types of lipids separately. Also, be sure to describe at the molecular level how each nutrient is absorbed into the animal’s body and where that absorption would occur.

Answer 1

Nutrients and their sites for absorption in different parts digestive system

Stomach:

Absorption of water and simple sugars

Small intestine:

Main site for the absorption of digested food is small intestine.

Absorption of glucose, fructose, fatty acids, glycerol and amino acids are absorbed through the mucosa into the blood stream and lymph

Large intestine:

Here least absorption occurs.

Absorption of water, sodium, potassium, chloride, and some of the Vitamin K produced by bacteria occurs in large intestine

Molecular mechanism of absorption

The end products of digestion reaches to blood or lymph through the intestinal mucosa by the process of absorption.

Absorption is achieved by following strategies

• Passive transport: Passive transport is attributed to concentration gradient. For example, small amounts of monosacharides like glucose, amino acids and some of electrolytes like chloride ions are generally absorbed by simple diffusion. Transport of water depends upon the osmotic gradient
• Active transport: This type of transport occurs on expense of energy. Several nutrients including amino acids, glucose, Na+ are absorbed into the blood through active transport.
• Facilitated transport: Fructose and some amino acids are absorbed with the help of the carrier ions like Na+ ion. The transport following this mechanism is called the facilitated transport

Absorption of Fatty acids and Glycerols

As we know that, fatty acids and glycerol are insoluble, they cannot be absorbed into the blood. To achieve the absorption of fatty acid and glycerols, they are first incorporated into small droplets called micelles which move into the intestinal mucosa.

Further, they are re-organised into very small protein coated fat globules called the chylomicrons that are transported into the lacteals (lymph vessel) in the villi.

Lymph vessels release the absorbed substances into the blood stream.