1.9 ANFs - T2

Question 1

What do anti-nutritional factors interfere with?

Answer 1

The digestion, absorption, and utilization (metabolism) of dietary nutrients

Question 2

Are mycotoxins regarded as ANF?

Answer 2

Generally not; they have a toxic effect rather than interfering with nutrition

Question 3

What are the 4 depressive effects of ANFs?

Answer 3

1. Protein digestion and utilization
   - trypsin/chymotrypsin inhibitors
   - lectins
   - tannins
2. Carbohydrate digestion
3. Mineral digestion and utilization (phytase)
4. Inactivate vitamins or increase vitamin requirement (anti-vitamins)

Question 4

What is the stimulative effect of ANFs?

Answer 4

Stimulate immune system (antigenic proteins)

Question 5

What ingredients are trypsin and chymotrypsin inhibitors found in? What do they do?

Answer 5

Legume seeds, especially soybean
- this is why we don’t feed whole soybeans

Bind irreversibly to the protease
- unable to cleave peptide bonds
- decrease protein digestion and utilization

Question 7

What are the physiological responses to trypsin and chymotrypsin inhibitors (protease inhibitors) in pigs and poultry?

Answer 7

Protein digestibility decreases
- body recognizes there is undigested protein going farther down the digestive tract

Question 8

Where are trypsin and chymotrypsin produced?

Answer 8

Pancreas
- as ANFs increase, pancreas has to work harder to produce more

Question 9

How are protease inhibitors related to protein status?

Answer 9

Harder to digest protein = harder to absorb AA

Question 10

How are protease inhibitors related to pancreas hypertrophy?

Answer 10

Stimulation of the pancreas to produce more trypsin and chymotrypsin
- can lead to hypertrophy bc it is having to work harder and harder to produce

Question 11

What are two types of protease inhibitors? How can they destroyed?

Answer 11

1. Kuntz
2. Bowman-Birk

Can be destroyed using heat (ie heat labile)

Question 12

How do pigs respond to increasing levels of protease inhibitors? How does this affect total N flow and Endo N flow?

Answer 12

• Respond by consuming more feed
• Total N flow increases (due to increased feed intake)
• Endo N flow increases bc of increase in trypsin and chymotrypsin production

Question 13

What are lectins also called? Why? What do they bind?

Answer 13

Hemagglutinins; bc they will cause RBC to clump together

Bind specific sugars and oligosaccharides
- on animal cell membranes
- in intestine; bind villi which reduces SA of gut wall

Question 14

What are 5 effects of lectins?

Answer 14

1. Damage of gut wall
2. Immunological reactions
3. Impaired absorption of nutrients
4. Increased synthesis of mucosal protein (endogenous losses)
5. Metabolic toxicity

Question 15

How can lectins be destroyed?

Answer 15

Heat
- heat labile

Question 16

What feed ingredients are lectins found in?

Answer 16

1. Common beans - highly toxic
2. Field pea and faba bean - less toxic

Question 17

In comparison to protease inhibitors, how do lectins relate to DM intake?

Answer 17

• Not as dramatic effect of DM increase
• Overall N flow increases; in part bc of increased feed intake
• Large increase in Endo N flow; due to increase production of mucus (has AA)

Question 18

What kind of compounds are tannins? What are the 2 categories?

Answer 18

Polyphenolic compounds (aka not proteins)
1. Hydrolyzable
2. Condensed (non-hydrolysable)

Question 19

What 3 feed ingredients are tannins found in?

Answer 19

1. Sorghum
2. Cottonseed meal
3. Faba bean

Question 20

What do tannins do?

Answer 20

• Form complex with enzymes or feed proteins
• Reduce protein digestibility
• Bitter taste

Question 21

What is phytate?

Answer 21

A complex compound that binds P, other minerals, and starch
- P digestibility is low in plant products
- Also other nutrients; minerals, AA, CHOs

Question 22

What is the major problem that phytate causes?

Answer 22

Phosphorus excretion
1. P intake (available and phytate P) = 100%
2. 30% can be used by the pig/chicken
3. 20% excreted via urine, 50% excreted via feces
4. urine + feces = slurry
- collected and spread on the land
5. Leads to eutrophication = proliferation of algae:
- killing other vegetation
- deoxygenating water
- algal toxins

Question 23

What 3 characteristics lead non-starch polysaccharides as being considered as ANF?

Answer 23

1. Digestibility
2. Passage rate
3. Viscosity (soluble NSO)

Question 24

What is a positive, functional property of NSPs?

Answer 24

Hindgut fermentation
- beneficial bacteria = decreased levels of potential pathogens

Question 25

What are 4 other ANFs?

Answer 25

1. Glucosinolates
   - cause palatability problems
   - impact on thyroid is poorly understood
2. Sinapine
   - rapeseed meal
   - no effect on nutrient digestion ; some metabolic effects
3. Vicine/convicine
4. Saponins
   - steroid bound to CHO- alfalfa, soy, canola, peas
   - bitter, reduced growth performance
   - form complexes with sterols

Question 26

What are a major ANF in canola co-products?

Answer 26

Glucosinolates
- Sulphur-containing secondary plant metabolites
- Present in vegetative and reproductive tissues of plants; serve as defense compounds
- Degraded by myrosinase
- Bitter taste = reduce voluntary feed intake
- Interference with synthesis of thyroid hormones involved in regulation of various metabolic processes = may affect metabolism and growth

Question 27

Is fibre an ANF?

Answer 27

Yes and no! Depends on your definition. Historically, considered the most common ANF but this is shifting.

YES
- reduces nutrient intake
- increases rate of passage
- physical barrier to nutrients

NO
- physical form encourages gut motility
- fibre fermentation by microbes produces beneficial byproducts
- positive effect on gut microflora

Question 28

What are mycotoxins?

Answer 28

Toxic compounds produced by fungi
- can be anti-nutritional and/or toxic
- can colonize/grow in the field
- can colonize in the field then grow in storage/transport
- can be difficult to detoxify; often heat stable
- can affect animal physiology
- can also contaminate animal products: meat, milk, eggs

Question 29

When are mycotoxins generally more of a problem?

Answer 29

In wet years/climates
- Specific mycotoxins need particular growing conditions: hot, cool, cool/warm cycle

Question 30

What do molds use mycotoxins to do?

Answer 30

Molds use mycotoxins to claim ownership of a resource
- “hey you crappy birds, get off of my lawn”

Question 31

Almost all field crops (esp. cereal grains) are contaminated to one extent or another with mycotoxins. When does this become a problem?

Answer 31

When specific mycotoxins are present above a particular level