Ruminal Lipid Metabolism

Question 1

What are the different types of categories of lipids?

Answer 1

1. Glycerol-based:
   -neutral (products of FA) - triacylglycerol
   -structural - glycolipids & phospholipids
2. Non-glycerol based:
   -sphingomyelins
   -waxes
   -steroids & sterols
   -vitamins
   -prostaglandins

Question 2

How much energy is produced from 1 mole of ATP?

Answer 2

52kJ / 12.4kcal

Question 3

How many moles of ATP are produced from 1 mole of glucose?

Answer 3

30 moles of ATP

Question 4

How many moles of ATP are produced from 1 mole of propionate?

Answer 4

15 moles of ATP

Question 5

How many moles of ATP are produced from 1 mole of acetate?

Answer 5

10 moles of ATP

Question 6

How many moles of ATP are produced from 1 mole of butyrate?

Answer 6

26 moles of ATP

Question 7

How many moles of ATP are produced from 1 mole of tripalmitin (lipid)

Answer 7

409 moles

Question 8

Where does beta-oxidation of fatty acids occur?

Answer 8

Mitochondria

Question 9

What are the main types of plant lipids in the diet?

Answer 9

Membrane lipid
Triacylglycerol
Diacylglycerol
Free fatty acids
Linolenic acid
Linoleic acid
Palmitic acid

Question 10

What are the main types of lipids in beef?

Answer 10

Monounsaturated fatty acids
Saturated fatty acids (SFA)
Polyunsaturated fatty acids (PUFA)
Linolenic acid
Alpha-linolenic acid
Eicosapentaenoic acid
Docosahexaenoic acid

Question 11

What is the recommended dietary Polyunsaturated fatty acids: saturated fatty acids ratio?

Answer 11

> 0.45

Question 12

What is the recommended dietary Omega-6:Omega-3 ratio?

Answer 12

<4
(balance of pro & anti inflammatory prostaglandins & eicosanoids)

Question 13

What & of the diet in ruminants should be made up of DM free oil?

Answer 13

(maximum) 6%

Question 14

What is the purpose of polyphenol oxidase (PPO) in red clover?

Answer 14

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

Question 15

Where does de novo synthesis of fatty acids occur?

Answer 15

Mammary gland

Question 16

What are some causes of milk fat depression?

Answer 16

1. Too much polyunsaturated lipid (PUFA) in the diet
   - plant oils/cod liver oil
2. Low roughage/high concentrate
   - low fibre in the diet
   - low feeding frequency
   - finely ground roughage

Question 17

What are the consequences of milk fat depression?

Answer 17