Ruminant Lipid Metabolism

Question 1

What are the two types of lipid

Answer 1

Glycerol based and non-glycerol based

Question 2

What are the two structural types of glycerol-based lipids?

Answer 2

Glycolipids and phospholipids

Question 3

Where are Glycolipids found?

Answer 3

They are high in grasses and grain and can be present in antigens

Question 4

Where are phospholipids found?

Answer 4

In the kidney, liver, heart, plasma membrane and cephalin

Question 5

what is cephalin?

Answer 5

It’s a phospholipid molecule made up of amino acids and fatty acids. It’s found in most cell plasma membranes, particularly in brain tissue

Question 6

What category does triacylglycerol come under?

Answer 6

It’s a neutral glycerol-based lipid

Question 7

What are the 5 types of non glycerol-based lipids?

Answer 7

1. Sphingomyelins
2. Waxes- which are meaningless in nutritional value
3. Steriods and Sterols
4. Vitamins
5. Prostaglandins

Question 8

How much energy can you get from 1 mole of ATP?

Answer 8

52 kJ, which is 12.4 kcal

Question 9

how many moles of ATP can you get from 1 mole of tripalmitin (lipid)?

Answer 9

409 Moles

Question 10

How is the energy released from a fatty acid?

Answer 10

Beta oxidation in the mitochondria, generating acetylCoA which enters citric acid cycle

Question 11

What is a saturated fatty acid?

Answer 11

No C=C double bonds

Question 12

What is a monoenoic fatty acid?

Answer 12

Unsaturated, one C=C double bond, EG nomenclature for cis-9-octadecenoic, commonly known as oleic= C18:1n-9 The double bond is on the 9th carbon

Question 13

What is a polyunsaturated fatty acid?

Answer 13

More than one double bond

Question 14

Describe the nomenclature for polyunsaturated fatty acids.

Answer 14

C18:2n-6 18 carbons, 2 double bonds, first double bond on the 6th carbon
9,12- octadecadienoic

Question 15

What is PUFA?

Answer 15

Polyunsaturated Fatty Acid

Question 16

Give some examples of PUFAs

Answer 16

veg
oil
canola
avocado
nuts
fish fat

Question 17

Give some examples of SFA

Answer 17

Milk
butter
bacon
some fish

Question 18

What should the PUFA : SFA ratio be? To maintain healthy cell function and membrane fluidity

Answer 18

> 0.45

high consumption of PUFA

Question 19

What is Omega-6?

Answer 19

n-6 series of fatty acids, the first double bond found on the 6th carbon.

Question 20

What is omega-3?

Answer 20

The n-3 series, where the first C=C is found on the 3rd carbon

Question 21

What is an eicosanoid

Answer 21

• Has a diverse role in the body, used in immunity
• created after oxidation of fatty acids thats are at least 20 C long, originate from omega 6 family- more anti-inflammatory properties. Omega-6 have pro inflammatory properties
• Messengers in the CNS

Question 22

What is the ideal ratio of omega6 : omega 3?

Answer 22

<4 to balance pro and anti inflammatory

Question 23

what does NDF stand for?

Answer 23

neutral detergent fiber

this is the quantity of fiber in feed we can use in ruminal nutrition

Question 24

how much fiber can be taken by the animal

Answer 24

= apparent digestibility

Question 25

what is the maximum percentage of fat in a ruminants diet?

Answer 25

5-6%

Question 26

What are the main source of ruminal lipids?

Answer 26

Plant lipids: 75% membrane lipid, 10% triacylglycerol, 10% diacylglycerol, 5% free fatty acid

Question 27

What are the fatty acid types in beef?

Answer 27

• Polyunsaturated Fatty acids (5%)
• linoleic acid
• alpha-linolenic acid
• eicosapentaenoic acid
• docosahexaenioc acid

Question 28

What is biohydrogenation?

Answer 28

microbes in the rumen taking advantage of lipids, but we want PUFA in our feed sources and so try to avoid this process

Question 29

where does green odour come from?

Answer 29

fatty oxidation

Question 30

what prevents lipolysis within a plant cell?

Answer 30

Red Clover Polyphenol

Question 31

what reduces biohydrogenation?

Answer 31

Plant secondary metabolites, protozoa within the rumen

Question 32

what does the protozoa in the rumen do to prevent biohydrogenation?

Answer 32

Engulfs organelles, not allowing bacteria in rumen to attack the lipids in the organelles membranes

Question 33

What is the effect of red clover versus grass on milk PUFA?

Answer 33

Red Clover increases PUFA in milk

Question 34

What does Red Clover contain?

Answer 34

Polyphenol oxidase

Question 35

What does polyphenol oxidase do?

Answer 35

• oxidises phenols to quinones in the presence of oxygen
• quinones are very reactive
• quinones bind to proteins to give protein-quinone complexes

Question 36

What effect does the binding of quinones to proteins have?

Answer 36

doesn’t allow bacteria to attack the complex, preventing biohydrogenation of the fatty acids

Question 37

where does Milk get/ synthesis fatty acids

Answer 37

• de novo synthesis within the mammary gland

- mammary uptake of complete fatty acids

Question 38

which fatty acids are synthesised de novo in mammary tissue?

Answer 38

All of C4- C14 and half of C16

from acetate and 3-OH-butyrate

Question 39

what fatty acids are taken up complete by the mammary tissue?

Answer 39

half of C16, all of C18 and longer

from diet and adipose tissue if loosing weight

Question 40

What is milk fat depression?

Answer 40

A decrease in milk fat, lowered by up to 50%

-no change in lactose or protein

Question 41

What types of feeding cause milk fat depression?

Answer 41

1. highly polyunsaturated lipid in diet

2. Low roughage/ high concentrates

Question 42

Where would highly polyunsaturated lipid in diet come from?

Answer 42

• plant oils/cod liver oil

- oil seeds or straight lipids

Question 43

how would low roughage/high concentrates be fed to animals?

Answer 43

• low frequency feeding

- finely ground roughage

Question 44

Where would the greatest decline of source of fatty acids be?

Answer 44

From De novo synthesis

Question 45

what is increased in the milk in milk fat depression?

Answer 45

C18:1 fatty acids

Question 46

What is SREBP?

Answer 46

Sterol response Element Binding Protein