Citric Acid Cycle and Feedstuffs

Question 1

What are the 3 ways pyruvate is used after glycolysis?

Answer 1

1. Fatty acid synthesis.
2. Lactate formation (Anaerobic conditions only).
3. Citric acid/Kreb’s cycle (Most common).

Question 2

Where does the citric acid cycle happen?

Answer 2

In the mitochondria, due to requiring aerobic conditions.

Question 3

How is ATP created in the citric acid cycle?

Answer 3

The complete oxidation of acetyl-CoA, oxidation of NAD+ into NADH + H^+, and the oxidation of FAD+ into FADH_2.

Question 4

What enzyme is required to convert pyruvate into acetyl-CoA?

Answer 4

Pyruvate dehydrogenase.

Question 5

What co-factors are required to convert pyruvate into acetyl-CoA?

Answer 5

The oxidation of NAD+ into NADH +H^+. CoA goes in and CO2 comes out.

Question 6

What enzyme is required to convert acetyl-CoA (in combination with oxaloacetate) into citrate?

Answer 6

Citrate synthase.

Question 7

What co-factors are required to convert acetyl-CoA (in combination with oxaloacetate) into citrate?

Answer 7

H2O goes in. CoA comes out, now having been separated from acetyl.

Question 8

What enzyme is required to convert citrate into isocitrate?

Answer 8

Aconitase.

Question 9

What enzyme is required to convert isocitrate into alpha-ketoglutarate?

Answer 9

Isocitrate dehydrogenase.

Question 10

What co-factors are required to convert isocitrate into alpha-ketoglutarate?

Answer 10

The oxidation of NAD+ to create NADH + H^+. The release of a CO2.

Question 11

What enzyme is required to convert alpha-ketoglutarate into succinyl-CoA?

Answer 11

Alpha-ketoglutarate dehydrogenase.

Question 12

What co-factors are required to convert alpha-ketoglutarate into succinyl-CoA?

Answer 12

The oxidation of NAD+ into NADH + H^+. CoA goes in and CO2 goes out.

Question 13

What is important about the formation of succinyl-CoA?

Answer 13

At this point in the citric acid cycle, pyruvate is completely oxidized.

Question 14

What enzyme is required to convert succinyl-CoA into succinate?

Answer 14

Succinyl-CoA synthetase.

Question 15

What co-factors are required to convert succinyl-CoA into succinate?

Answer 15

ADP + Pi goes in. ATP and
CoA goes out.

Question 16

What enzyme is required to convert succinate into fumarate?

Answer 16

Succinate dehydrogenase.

Question 17

What co-factors are required to convert succinate into fumarate?

Answer 17

The oxidation of FAD+ into FADH_2.

Question 18

What enzyme is required to convert fumarate into malate?

Answer 18

Fumarase.

Question 19

What co-factor is required to convert fumarate into malate?

Answer 19

H2O goes in.

Question 20

What enzyme is used to convert malate into oxaloacetate?

Answer 20

Malate dehydrogenase.

Question 21

What co-factor is required to convert malate into oxaloacetate?

Answer 21

The oxidation of NAD+ into NADH + H^+.

Question 22

How many ATP are produced from NADH+H^+?

Answer 22

25 from 10 H^+.

Question 23

What is the ATP equivalency of NADH + H^+?

Answer 23

2.5 ATP.

Question 24

How many ATP are produced from FADH_2?

Answer 24

9 from 6 H^+.

Question 25

What is the ATP equivalency of FADH_2?

Answer 25

1.5 ATP.

Question 26

At what 2 steps is the citric acid cycle regulated?

Answer 26

1. Pyruvate dehydrogenase. 2. Isocitrate dehydrogenase.

Question 27

What is pyruvate dehydrogenase activated by?

Answer 27

Insulin, preventing gluconeogenesis.

Question 28

What is isocitrate dehydrogenase regulated by?

Answer 28

Inhibited by an increase in the NADH + H^+: NAD+ ratio in the cell. Stops the reaction to prevent running out of NAD+.

Question 29

What is citrate a substrate for?

Answer 29

Fatty acid synthesis.

Question 30

What are the 2 mitochondrial membranes?

Answer 30

1. Outer. 2. Inner.

Question 31

What is the function of the outer membrane?

Answer 31

Encompass the whole mitochondrion and forms the outer surface of the mitochondrion.

Question 32

What is the function of the inner membrane?

Answer 32

Has transporters for different compounds. Controls what enters and leaves the mitochondrion.

Question 33

What is the nutrient composition of a concentrate?

Answer 33

1. Low in fiber. 2. High in energy or protein.

Question 34

What are energy concentrates?

Answer 34

Concentrates that are high in energy.

Question 35

What are protein concentrates?

Answer 35

Concentrates that are high in protein.

Question 36

What is the nutrient composition of a roughage?

Answer 36

1. High fiber. 2. Low nutrient density.

Question 37

What are feed additives?

Answer 37

Any substance, other than concentrates and roughages, intentionally added to a diet/ration. ex: Vitamin, mineral, amino acid, drug, enzyme.

Question 38

What family are cereal grains from?

Answer 38

The grass family.

Question 39

What are cereal grains the primary energy source for?

Answer 39

1. Non-ruminant animals. 2. Ruminant animals.

Question 40

What is the most important feed grain?

Answer 40

Corn.

Question 41

Why is corn the most important feed grain?

Answer 41

1. Highest DE content of all cereal grains. 2. Overproduced. 3. Inexpensive.

Question 42

What is the energy profile of corn?

Answer 42

1. High in starch. 2. High in unsaturated fats. 3. Roughly 4% oil. 4. Low in fiber.

Question 43

What is the protein profile of corn?

Answer 43

1. 9% CP. 2. Poor quality protein (insufficient amount of essential amino acids) because of the high zein (protein) content.

Question 44

What is the mineral profile of corn?

Answer 44

1. Low calcium. 2. High in unavailable phosphorous, usually bound to phytate.

Question 45

How is the unavailable phosphorous in corn made available to the animal?

Answer 45

The feed additive phytase.

Question 46

What is the vitamin profile of corn?

Answer 46

1. High vitamin A due to carotenoid pigments. 2. Xanthophylls (pigment, not vitamin). 3. Low in niacin (Vitamin B3).

Question 47

Why are carotenoid pigments and xanthophylls important?

Answer 47

They provide the yellow color to chicken legs, egg yolks, and the yellowish-tinge to meat.

Question 48

What is a deleterious factor associated with corn?

Answer 48

Aspergillus flavus.

Question 49

What is aspergillus flavus?

Answer 49

A fungus that grows on live and stored corn that releases aflatoxin, a type of mycotoxin.

Question 50

What are the preferred conditions for Aspergillus flavus growth?

Answer 50

Hot and humid conditions.

Question 51

What affects does aflatoxin have on animals?

Answer 51

1. Reduced feed intake. 2. Diarrhea. 3. Liver damage. 4. Reduced growth.

Question 52

What two cereal grains are good substitutes for corn?

Answer 52

1. Sorghum. 2. Millet.

Question 53

What type of environment do sorghum and millet grow in?

Answer 53

Semiarid tropics. *Corn cannot grow here.

Question 54

What type of feed is millet commonly found in?

Answer 54

Bird seed.

Question 55

What is the alternative name for sorghum?

Answer 55

Milo.

Question 56

What is the energy profile of sorghum*? *Millet has the same properties.

Answer 56

1. Similar to corn. 2. Requires processing (breaking the outer coating of the seed) to improve digestibility.

Question 57

What is the protein profile of sorghum?

Answer 57

1. 10% CP. 2. Poor quality (low availability of amino acids).

Question 58

What deleterious factor is associated with sorghum?

Answer 58

Condensed tannins in the seed.

Question 59

How do condensed tannins affect animals?

Answer 59

1. React with proteins and make them unavailable. Processing methods (chemicals) can overcome this. 2. Astringent flavor that reduces feed intake.

Question 60

What cereal grain is most commonly used for human consumption, and for animals only in excess?

Answer 60

Wheat.

Question 61

What is the energy profile of wheat?

Answer 61

Similar to corn.

Question 62

What is the protein profile of wheat?

Answer 62

13% CP.

Question 63

Where is wheat commonly found when given to animals?

Answer 63

In pellets due to wheat gluten acting as a binding agent.

Question 64

What is the deleterious factor of wheat?

Answer 64

Pentosans. (5-carbon sugar).

Question 65

What affect do pentosans have on animals?

Answer 65

Causes diarrhea due to its poor digestibility.

Question 66

What is the energy profile of barley?

Answer 66

Lower than corn.

Question 67

What is the protein profile of barley?

Answer 67

12% CP.

Question 68

What is the mineral profile of barley?

Answer 68

Phosphorous bound to phytate. *Phytase needs to be added.

Question 69

What is the deleterious factor of barley?

Answer 69

Contains beta-glucans.

Question 70

What affect does beta-glucans have on animals?

Answer 70

1. Reduces digesta flow rate and lipid absorption. 2. Causes sticky excreta in poultry, blocking the vent and cloaca. *Counteracted using glucanases.

Question 71

Why are oats most commonly used for humans (horses being the exception)?

Answer 71

Oats are expensive.

Question 72

What is the energy profile of oats?

Answer 72

1. Low. 2. High in soluble fiber. 3. Can be processed (flaked, rolled) to improve digestibility.

Question 73

What is the protein profile of oats?

Answer 73

1. 12% CP. 2. High quality protein.

Question 74

What is the energy profile of rye?

Answer 74

Similar to barley and oats.

Question 75

What is the protein profile of rye?

Answer 75

12% CP.

Question 76

What is the deleterious factor associated with rye?

Answer 76

Ergot.

Question 77

What is ergot?

Answer 77

A fungus that grows on rye grass and other grasses that produces compounds that cannot be combated by feed additives.

Question 78

What does ergot do to animals?

Answer 78

1. Necrosis of the extremities (hoof tips, ear tips, tail tips). 2. Abortions. 3. Agalactia. 4. Reduced growth.

Question 79

What are the deleterious factors of rye?

Answer 79

1. Pentosans. 2. Pectins.

Question 80

What do pectins do to animals?

Answer 80

1. Poor growth. 2. Binds feedstuffs, limiting digestibility. 3. Sticky excreta.

Question 81

What seed is normally provided alongside cereal grains?

Answer 81

Buckwheat.

Question 82

What is the energy profile of buckwheat?

Answer 82

Similar energy to corn.

Question 83

What is the protein profile of buckwheat?

Answer 83

1. 11% CP. 2. High quality protein.

Question 84

What deleterious factor is in buckwheat?

Answer 84

Fagopyrins.

Question 85

What effect does fagopyrin have on animals?

Answer 85

It causes photosensitization in light-skinned animals, leading to skin lesions.

Question 86

What animals are unaffected by most of the deleterious factors in carbohydrates?

Answer 86

Ruminants, due to the microbes in the rumen breaking down the compounds.

Question 87

What is the carbohydrate profile of liquid molasses?

Answer 87

48% sugar.

Question 88

What is the protein profile of liquid molasses?

Answer 88

3-4% CP.

Question 89

What is the maximum % of the diet that liquid molasses can be?

Answer 89

30%, otherwise it has a laxative effect.

Question 90

What % of the diet does liquid molasses normally compose?

Answer 90

2-5%.

Question 91

Is liquid molasses fed to meet carbohydrate requirements?

Answer 91

No, it is fed for palatability.

Question 92

What animals can develop molasses toxicity?

Answer 92

Ruminants.

Question 93

How does molasses toxicity occur?

Answer 93

Molasses, when fed with inadequate forages causes the overproduction of butyrate by microbes, leading to ketosis. Causes blindness and incoordination.

Question 94

What are dried by-products?

Answer 94

What is leftover after products for human consumption have been made.

Question 95

What are 3 common dried by-products?

Answer 95

1. Beet pulp. 2. Dried citrus pulp. 3. Dried bakery by-product.