Metabolism and Energetics

Question 1

Energy metabolism overview

Answer 1

Question 2

Role of glucose

Answer 2

Glucose must be regulated
-important energy source
-brain tissues cannot synthesize glucose so depend on blood glucose

Question 3

How is glucose regulated?

Answer 3

insulin and glucagon

Question 4

Insulins role as an anabolic

Answer 4

-Increases glucose and amino acid uptake by cells
resulting in synthesis of glycogen stores in liver/muscles, protein in muscle, and triacylglycerols in adipose tissue

Question 5

Steps after a meal

Answer 5

1. Food broken into Carbohydrates (glucose, fructose, galactose) converted into pyruvate then Acetyl coA. Can also store as glycogen
2. Used in Kreb’s cycle

Question 6

Steps for a short fast

Answer 6

1. Glycogen is used to make glucose because no food to do so
2. Becomes pyruvate
3. acetyl coA
4. Kreb’s cycle

Question 7

Use of lipids

Answer 7

1. Lipids (fatty acids and glycerol) undergo beta-oxidation to make acetyl-CoA
   *Acetyl coA used to make ketone bodies when needed
2. More rarely, lipids (glycerol, and odd chain FAs) undergo gluconeogenesis to make pyruvate

Question 8

What is being used during a medium fast?

Answer 8

1. Nitrogen pool amino acids undergo gluconeogenesis to make pyruvate
2. Lipids (glycerol, odd chain FAs) undergo gluconeogenesis to make pyruvate

Question 9

Glucogenic vs. ketogenic aa

Answer 9

Glucogenic- used to make pyruvate

Ketogenic- only produce ketones

Question 10

During starvation

Answer 10

1. Use protein pool; breaking down tissues and cells
2. some make pyruvate but mostly making acetyl coA to be used to make ketones
3. Ketones provide energy to the brain

Question 11

Post prandial period

Answer 11

-glucose is exogenous
-all tissues using it
-brain receives energy from glucose

Question 12

Short to medium fast period

Answer 12

-gets glucose from glycogen and gluconeogenesis
-all tissues using except liver/muscles because they are supplying it
-brain receives energy from glucose

Question 13

Long fast period

Answer 13

-getting glucose from gluconeogenesis
-brain is using it
-brain receiving energy from glucose

Question 14

Starvation period

Answer 14

-no glucose sources; must use ketone bodies
-brain is using it
- brain gets energy from ketone bodies

Question 15

Measuring glycemic index

Answer 15

-Ratio between the quickly digested blood glucose and the slower digested blood glucose x 100
*works well for omnivores, not ruminants or carnivores

-easy digest= immediate peak in glucose
-harder to digest= slower peak and not as high so less glucose but longer sustained (will feel fuller longer)

Question 16

What occurs with the consumption of a high glycemic load meal?

Answer 16

=weight gain= don’t want this in small animal but do want in large production animals

Question 17

What occurs with consumption of low glycemic load meal?

Answer 17

Question 18

Why do glycemic responses not work well for carnivores?

Answer 18

1. Because they evolved to consume high protein, low carbohydrates diets
   -results in high rates of gluconeogenesis even after a meal
   -aa’s such as arginine can stimulate insulin release
2. May appear glucose intolerant if fed high carbohydrate diet
   -leads to hyperglycemia (often prolonged) from continued gluconeogenesis and glucose surge from meal

Question 19

Diet formulations in pigs

Answer 19

-corn starch has very high glycemic diets=100
-high glycemic barley= 71
-low glycemic barley= 49

Question 20

N utilization/retained N

Answer 20

-How much N from feed ends up in the pigs and is used
-both corn and high glycemic barley lead to higher levels of N
-Anabolic effects of high glycemic effect wanted in large animal because means increased weight gain

Question 21

What does fat do to glycemic index?

Answer 21

Fat will decrease gastric emptying resulting in less get through at a time which will decrease glycemic index