1.7 Feedstuffs - Cereals

Question 1

What are cereal grains?

Answer 1

Edible grains of cultivated grasses
- ex. wheat, rice, corn barley, oats, rye sorghum, triticale, buckwheat

Question 2

What is the most important cereal grain for pigs? Poultry?

Answer 2

Pigs: barley (prairies), corn (globally)
Chickens: wheat (prairies), corn (globally)

Question 3

What is the basic structure of all cereal grains?

Answer 3

1. Hull
   - Fibre (NSP)
2. Aleurone
   - Fibre (NSP) + protein
3. Endosperm
   - Starch
   - highly developed
4. Germ
   - Oil (fat) + protein

Question 4

Pertaining to the type of cereal grain, as there are more soluble NSPs present, what is there less of?

Answer 4

DE
- ex. corn has the highest DE, oats have the lowest DE

Question 5

What are the 2 forms of starch?

Answer 5

1. Amylose
   - long chains of a1-4 linked glucose units
   - tight helical structure
   - more resistant starch
2. Amylopectin
   - some a1-6bonds with branches
   - higher digestibility than amylose

Question 6

Why is starch gelatinized?

Answer 6

• Causes granules to swell and lose crystallinity
• Higher digestibility
• The protein matrix is a potential barrier so needs to be broken

Question 7

Where are starch granules found?

Answer 7

Within the protein matrix
- which is a potential barrier
- also GE digestibility ~ CP digestibility

Question 8

What does the rate of degradation of starch granules depend on?

Answer 8

Proportion of amylose vs amylopectin
- rapid digestible starch
- moderate rapid digestible starch
- moderate slow digestible starch
- slow digestible starch

Question 9

What does non digested starch act like?

Answer 9

Fiber = substrate for microbial fermentation

Question 10

What 2 things is corn high in?

Answer 10

1. UFA
2. carotenoid pigments

Question 11

What is the effect of corn FAs on pork quality?

Answer 11

• high levels of UFA
• negative effect on quality bc carcass FA composition reflects dietary comp
• UFA very liquid at room temp = greasy pork

Question 12

What is the effect of corn carotenoids on chicken and egg yolk appearance?

Answer 12

Colour!
- yellow chicken skin

Question 13

Why are oats high in fat, yet low in DE?

Answer 13

Bc oats are high in fiber

Question 14

Protein quality of cereal grains

Answer 14

wheat > barley and oats > corn

*feed cereal grains bc of the starch (energy) they provide but still contain protein; bc most of the diet is composed of cereal grain, they contribute a substantial proportion of CP

Question 15

Fiber/soluble NSP in cereal grain

Answer 15

Oats > Barley > Wheat & Cron
- Barley contains B-glucans = supplement B-glucanase
- Wheat contains arabinoxylans = supplement xylanase
- w/o supplementing enzymes, the soluble NSP is fermented by the microbes instead

Question 16

Can animals break down B bonds of CHO?

Answer 16

NO! But microbes can
- can supplement enzymes as well

Question 17

What is the potential problem with soluble fibre/NSP? How is this controlled?

Answer 17

Soluble fibres in gut:
- decreases diffusion of digestive enzymes, nutrients
- increases bacterial load
- sticky feces

Control by using supplemental enzymes
- Arabinoxylanase, B-glucanase
- match enzyme activity to the major NSP(s) present

Question 18

What 4 aspects of cereal grains have been genetically modified?

Answer 18

1. Starch form and availability
   - amylose vs. amylopectin
   - fermentable vs. digestible starch
2. AA content
   - high-lysine corn and barley
3. Oil content
   - high-oil corn
4. Phosphorus digestibility
   - low-phytate corn and barley = decrease in ANF

Question 19

What is the nutritional value of oat hull removal?

Answer 19

Dehulling removes indigestible NSP
- left with oat groats and oat hulls
- groats: highly digestible
- hulls: virtually non-digestible

Question 20

Barley fractionation

Answer 20

• removal of barley hull
• hull-less barley can be genetically selected for

Question 21

What is ‘fractionation’?

Answer 21

Dehulling! Which contains the NSPs

Question 22

Energy content of cereal grains

Answer 22

corn > wheat > barley
*barley and wheat are the main grains in AB