Simple Stomach 2

Question 1

What have enzymes been developed to do?

Answer 1

-incorporated into feeds to aid in digestion

Question 2

What characteristics where developed into the enzymes?

Answer 2

-heat stability
-free flowing for handling ease when incorporated into diets
-stability for storage and feeding

Question 3

What is the intention of adding feed enzymes to feedstuff?

Answer 3

-enhancing nutrient digestion
-maximizing digestible nutrients
-liberate nutrients

Question 4

What is Xylans

Answer 4

-type of hemicellulose
-non-starch polysaccharide
-contains pentose xylose sugar

Question 5

What does Xylan contribute to?

Answer 5

-cell wall of the plant

Question 6

Where are Xylans found? and what is it?

Answer 6

-in feedstuffs
-as fiber has limited digestibility in non-ruminants

Question 7

Why was Xylanase developed?

Answer 7

-to breakdown xylans in feed during digestion

Question 8

What is beta-Glucans?

Answer 8

-another type of plant cell wall carbohydrate
-undigestible like xylan

Question 9

Why was beta-GLucanase enzyme developed?

Answer 9

-to breakdown Beta-Glucan found in diets associated with feedstuffs

Question 10

What are Xylans and beta-Glucans believed to do?

Answer 10

-bind nutrients
-restricting availability
-potentially influences digesta viscosity influencing nutrient absorption from the lumen in the gut

Question 11

What does Proteases do?

Answer 11

-an enzyme that is incorporated into feeds that enhance protein hydrolysis
-intent is to support amino acid availability

Question 12

What is the purpose of enzymes?

Answer 12

-improve nutrient utilization for health of animals

Question 13

Who is enzymes most marketed towards?

Answer 13

-non-ruminants

Question 14

What is the presumption for proteases?

Answer 14

-digestive enzyme capacity is insufficient for dietary protein levels

Question 15

What is the presumption for xylanases and beta-Glucanases?

Answer 15

-these fibers could yield energy or are otherwise impacting nutrient availability

Question 16

What does phytate do?

Answer 16

-hold on tight to phosphorus and minerals

Question 17

What is phytate?

Answer 17

-also known as phytic acid
-inositol hexaphosphate
-storage form of phosphorus in cereal grains and oilseeds
-chelates: binds metal ions

Question 18

What are Chelates and what do they do?

Answer 18

-Bind Zinc, Calcium, and Iron
-Chelation of these ions and others limit their bioavailability
-Absorption of minerals from phytate containing diets can be restricted

Question 19

How much phosphorus in seeds is found in phytate form?

Answer 19

50-80%

Question 20

Since phytate phosphorus is poorly digestible what happens to the diet?

Answer 20

-diets are supplemented with additional inorganic sources (like dicalcium phosphate) to meet requirements

Question 21

When supplements are added to the diet like dicalcium what does it do?

Answer 21

-This effectively increases the total phosphorus in the diet
-with phytate phosphorus lost in manure

Question 22

What is phosphorus essential for? a pollutant of?

Answer 22

-essential for plants and animals
-be a pollutant in water along with nitrogen (both found in manure and waste)

Question 23

Phytate in animals, bacteria, and fungi

Answer 23

-Animals lack the phytase enzyme
-some bacteria and fungi produce it

Question 24

How has the bioavailability of phosphorus from feedstuffs improved?

Answer 24

-by isolating phytase genes and producing them through biotechnology as feed additives

Question 25

What does phytase partially liberate?

Answer 25

-improves bioavailability (both of phosphorus and minerals)
-reduces the total phosphorus in the diet from inorganic sources and therefore excreted phosphorus

Question 26

What does phytate chelate minerals include?

Answer 26

trace minerals

Question 27

Are trace minerals (their ions) important for other functions?

Answer 27

Yes

Question 28

What are many brush border peptidases?

Answer 28

-Metalloenzymes

Question 29

What is a metalloenzyme?

Answer 29

-enzymes that include a mineral ion in the catalytic portion of the enzyme responsible for enzyme activity

Question 30

What can phytate do to metalloenzyme in the digesta?

Answer 30

-can be chelated: bound, rendered ineffective

Question 31

What can feeding phytase do?

Answer 31

-improve protein digestion digestibility

Question 32

What does TDN stand for?

Answer 32

Total Digestible Nutrients

Question 33

What is TDN?

Answer 33

-energy system sometimes applied to ruminants and swine
-roughly similar to DE
-not expressed in energy units, expressed as a weight or percentage
-roughly converted to energy values

Question 34

What is TDN getting replaced by?

Answer 34

The net energy system

Question 35

Hoe many kcal De per pound of TDN?

Answer 35

2000 kcal

Question 36

What do digestion trials identify when calculating TDN?

Answer 36

-digestible protein
-carbohydrates
-lipids

Question 37

What are carbohydrates called in TDN?

Answer 37

-nitrogen free extract
-crude fiber

Question 38

What do carbohydrates represent in TDN?

Answer 38

-the non fiber carbohydrate and fiber, but these identities are not pure or clear

Question 39

What are lipids estimated from in TDN?

Answer 39

ether extract

Question 40

What does ether extract capture?

Answer 40

-fats in feeds
-but also non-nutritive lipids like pigments

Question 41

What is ether extract multiplied by? and why?

Answer 41

-2.25
-to reflect added energy density of fats compared to carbohydrates

Question 42

What is feed TDN calculated from?

Answer 42

-digestibility experiments that are many decades old

Question 43

What are problems with TDN?

Answer 43

-intake levels were lowers in the experiments and digestibility is known to be influences by intake level
-feeds are variable in quality depending on conditions and ascribing TDN values for a specific feedstuff years ago has limitations in application today
-reporting of crude fiber in feed analyses has been replaced with estimates of fiber based on the detergent fiber system