Lecture 15 lipids and Ruminants

Question 1

Whos diet are normally quiet low in lipids? and why?

Answer 1

Herbivores, 2-5% because plan food contains very small quantities of lipids

Question 2

What is altered extensively by the rumen fermentation?

Answer 2

Plant lipids
The lipid actually received and absorbed by the animal differs from that ingested.

Question 3

What is the ruminant intolerant to ?

Answer 3

High levels of fat, which may disrupt fermentation.

Question 4

What are toxic to microbes?

Answer 4

Excess fatty acids

Question 5

Where do ruminants obtain lipids from? what sources?

Answer 5

1-Forages (Glycolipids)
2-Grains&Concentrates(Triglycerides)
3- Fat Supplements (added to diet to increase energy density)

Question 6

What are the usual fat sources in ruminants diet?

Answer 6

Oil seeds and animal fat supplementation

Question 7

What is supplemented as an energy source in ruminants?

Answer 7

Dietary fats.
It proves more energy than carbohydrates.

Question 8

Why would fat be supplemented in a ruminant?

Answer 8

To match the nutrient requirement of high production

Question 9

What does too much fat in ruminant diet affect?

Answer 9

Digestibility

Question 10

What happens after esterified plan lipids are consumed?

Answer 10

They are hydrolysed extensively by microbial lipases, causing the release of fatty acids and a free glycerol

Question 11

What are lipases secreted by?

Answer 11

The microbes

Question 12

What does the lipase hydrolyse in ruminants?

Answer 12

Hydrolysis acylglycerols completely to
-Fatty acids
-Glycerol
-Galactose
(If the lipid was a galactose) with little accumulation of mono or diglycerides.

Question 13

What are rapidly fermented in the rumen?

Answer 13

Glycerol and Galactose, yielding VFA’s

Question 14

What are the 2 VFA’s that are primarily fermented from glycerol and galactose?

Answer 14

Propionic and Butyrate

Question 15

What happens during Rumen Biohydrogenation?

Answer 15

Dietary lipids are hydrolysed in the rumen to form free fatty acids and glycerol.

Question 16

Where are triglycerides found?

Answer 16

Animals, Plants, Humans

Question 17

Where are glycoproteins found?

Answer 17

Forages

Question 18

What are phospholipids made up of?

Answer 18

2 fatty acids + 1 phosphate group

Question 19

What are glycolipids made up of?

Answer 19

Glycerol with 2 fatty acids and 1 sugar “hanging off” SN3 position

Question 20

What are triglycerides made up of?

Answer 20

3 fatty acids hooked onto glycerol backbone

Question 21

What does biohydrogenation convert?

Answer 21

Unsaturated fatty acids to saturated fatty acids.
They then take biochemical pathways.
They are Biohydrogenation intermediates.

Question 22

What must biohydrogenation have to be?

Answer 22

Must be a free fatty acid. If it remains as a TG, GL, PL then the FA cannot be hydrogenation.

Question 23

What happens to fatty acids that get more hydrogen?

Answer 23

they are more saturated

Question 25

What do unsaturated FA have a relatively short half of?

Answer 25

Lives in ruminal contents because they are rapidly hydrogenated by microbes to more saturated end products.

Question 26

Whats the initial step in biohydrogenation?(BH)

Answer 26

An Isomerization reaction that converts the Cis-12 double bond in unsaturated FA’s to a trans-11 isomer.

Question 27

What makes the isomerase functional?

Answer 27

a free carboxyl group, and in this case PUFA;s such as C18:2, a cis-9, cis-12 double bond configuration is present.

Question 28

What establishes lipolysis as a prerequest for biohydrogenation?

Answer 28

The requirement of a free carboxyl group establishes lipolysis as a prerequisite for biohydrogenation

Question 29

Name the 2 different types of fatty acid isomearse?

Answer 29

-cis
-trans

Question 30

What happens when isomerization occurs?

Answer 30

Cis oriented double bond is joined by bacterial isomerases to be then transferred to trans Oriented double Bond

Question 31

What is often not complete in terms of biohydrogenation?

Answer 31

The hydrogenation of linoleic and linolenic acid is often not complete

Question 32

What does the incompleteness of linoleic and linolenic acid provide?

Answer 32

It provides stearic acid and different monounsaturated isomers, of which trans vaccenic acid is characteristic of ruminal metabolism.

Question 33

What converts unsaturated double bonds to saturated bonds?

Answer 33

Bacterial Hydrolyses + H+

Question 34

Why biohydrogenation?

Answer 34

Because it relieves the rumen of excess hydrogen ions: generated from fermentation.

Question 35

Whats highly toxic to rumen bacteria?

Answer 35

PUFA’S

Question 36

Whats the survival process of bacteria?

Answer 36

PUFA’S, different bacteria do different things.

Question 37

What is the makeup of linoleic acid?

Answer 37

18:2

Question 38

Whats the make up of steric acid?

Answer 38

18:0

Question 39

What do ruminants consume alot of?

Answer 39

PUFA’S

Question 40

Whats the ruminant lipid characterised by?

Answer 40

A higher saturated fat content (often criticised for too much saturated fat)

Question 41

Whos is responsible for ruminant lipid?

Answer 41

Rumen biohydrogenation is responsible, ruminant lipid doesn’t resemble consumed FA

Question 42

What does a monogastric lipid resemble?

Answer 42

The FA profile of what the animal consumed