Carbohydrates

Question 1

Name some pentose monosaccharides

Answer 1

Arabinose
Xylose
Deoxyribose
Ribose

Question 2

Name some hexose monosaccharides

Answer 2

Fructose
Glucose
Galactose
Mannose

Question 3

Name some disaccharides

Answer 3

Cellobiose = Glucose + glucose
Maltose = Glucose + glucose
Lactose = Glucose + galactose
Sucrose = Glucose + fructose

Question 4

What is an oligosaccharide?

Answer 4

A sort of polysaccharide of 3+
Includes trisaccharide’s and tetra saccharides

Question 5

Name some polysaccharides

Answer 5

1. Pentosans (xylan, araban)
2. Hexosans (cellulose, starch)
3. Mixed polysaccharides (hemicellulose)

Question 6

How much carbohydrates are in forage and cereal grains?

Answer 6

70% of forage
80% of cereal grains

Question 7

Structural vs non-structural carbohydrates

Answer 7

Non-structural: starch, pectin, sugars
Structural: cellulose, lignin

Question 8

What sugars make up cellulose? Hemicellulose?

Answer 8

Cellulose: glucose (6C)
Hemicellulose: xylose (5C) and glucose (6C)

Question 9

What is lignin?

Answer 9

an indigestible carbon polymer used to provide structural support

Question 10

Which polysaccharides are rapidly and slowly degraded in the rumen?

Answer 10

Sugars are digested rapidly
Celluloses are digested slowly

Question 11

How do bacteria digest polysaccharides?

Answer 11

Bacteria secrete enzymes to break down polysaccharides into oligosaccharides and then monosaccharides.
Monosaccharides are transported to the interior of the bacteria cell which is broken down into pyruvate and VFAs

Question 12

What enzymes do bacteria secrete for digestion?

Answer 12

Amylase (pancreas)
Maltase (mucosal)
Isomaltase (mucosal)
Lactose

Question 13

Which VFA recovers the most energy from glucose?

Answer 13

Propionate

Question 14

Where does extra energy in the rumen go?

Answer 14

most goes to methane production during methanogenesis

Question 15

What are some ruminal based strategies to increase energy recovery from the diet?

Answer 15

Using ionophores

Question 16

What is the fate of each VFA during and after absorption?

Answer 16

Butyrate- 90% used by epithelial cells (TCA). 10% oxidized/stored in tissues
Proprionate- 10% used by epithelial cells (TCA). 90% converted to glucose in the liver
Lactate- converted to glucose in the liver
Acetate- 90% of circulating VFA. 10% converted to acetyl-CoA

Question 17

How does an ionophore work?

Answer 17

It an antimicrobial that changes ion transport in bacteria
Makes pores in cell wall, disrupting osmotic pressure

Question 18

What are some advantages of ionophores?

Answer 18

1. Inhibits coccidia
   2 increase growth rate and feed efficiency
2. inhibit gram (+) bacteria