Carbohydrates and Carbohydrate Flashcards
(72 cards)
1
Q
are carbs essential as an energy source
A
- no evidence suggests they require carbs but because their diet is mostly plants its over 50% of their diet
2
Q
what is the role of carbs in plants
A
- energy transformations ; for tissue synthesis ( glucose is a major building block, synthesize lipids and amino acids)
- energy reserve ( starch is the most important in plants )
- structural support for living plants ( cellulose and hemicellulose (carbs) lignin (non carb)
3
Q
what % of carbs is found in the animal body
A
<1% very little found in animal body
- in the form of glycogen (stored in liver and muscles) and glucose
4
Q
how do you classify monosaccharides?
which are most important on a nutrient bases
A
1 sugar unit
- glucose
- fructose (to make sucrose )
- galactose (lactose building block)
5
Q
how do you classify disaccharides and which are most important ?
A
2 sugar units
- lactose = milk sugar (made by glucose and galactose )
- sucrose ( made by glucose and fructose)
- maltose = aids in carb digestion in the small intestine (glucose and fructose)
6
Q
what classifies oligosaccharides
A
3-10 sugar
7
Q
how do you classify polysaccharides and which are the most important
A
- over 10 sugar units
- starch (glucose)
- glycogen (glucose)
- dietary fiber (cellulose hemicellulose)
8
Q
how can monosaccharides be classified
A
- number of c atoms
- pentoses and hexoses being the most important
9
Q
what is a chiral carbon and how is it important to nutrition
A
chiral carbons are asymmetrical enzymes with D and L forms on the 5 C
- OH on right = D
OH on left = L
- D is recognized by the enzymes of the digestive tract but L is not
10
Q
where does glucose come from
A
- commercial produced by hydrolysis of corn starch
- major end product of carb digestion
- ruminants produce FVA
11
Q
where does galactose come from
A
- glucose + lactose = found in plants
- component of galactolipids found in plants
12
Q
where does fructose
A
- sweetest of all sugars ( fruits and honey)
- component of sucrose
13
Q
how do you turn B-D ribose to B-D-2- deoxyribose
A
removal of oxygen from the second carbon
14
Q
what is the main function of ribose
A
combined with adenine it makes adenosine and 3 phosphates to make ATP
15
Q
what is ribitol
A
compenent of riboflavin (B2)
16
Q
how can beta and alpha bonds effect monogastric digestion
A
- monogastric
enzymes can digest alpha bonds like starches but not beta linkages like cellulose
17
Q
are ruminants able to digest beta bonds
A
yes, most forages found in ruminant diets are beta linkages
18
Q
where is lacrose naturally found
A
in milk
- galactose and glucose in B(1-4) glycosidic bond
broken down by lactase
19
Q
when is lactase expression most present
A
- early on in birth, can fade during life span = lactose intollerant
20
Q
what is maltose used for in digestion
A
- partial hydrolysis of starch yields maltose
21
Q
what is the difference between homo/ heteropolysaccharides?
A
homo - the same monosaccharide units = starch, thats only made of glucose - alpha
heter - made up of more then one monosaccharides
hemicellulose , glucose and others
22
Q
what are the two different types of starch granuels
A
- amylose
- amylopectin
23
Q
What is amylose
A
- long branch chains of glucose connected by a (1-4) linkage
- soluble in water - bur will adopt hylic structure, reducing the area for enzymes to digest = so its less digested
- 20-30% of starch in cereal grains
- also called resistance starch
24
Q
what is amylopectin
A
- branched - chained polymer with a (1-4) and a (1-6) linkages
- compromises 70-80% of starch in cereal grains
- de-branching enzyme a 1-6 requires glucosidase for digestion
- its rapidly digested because of its branched surfaces = more surface area for enzyme to digest it
25
what is glycogen
- very similar to amylopectin, more highly branched
- a(1-4) and a (1-6) linkages at branch points
- storage form of glucose in animals (readily available energy source)
- stored in liver and muscles
26
what is the difference between glycogen storage in the liver or in the muscles
- liver = the glycogen is used locally
- muscles = has to travel through the blood stream
27
what is cellulose
- long linear polymer of repeating glucose units in B(1-4) linkage (starch is a (1-4)
- insoluble in water
indigestible by mammalian enzymes (by fermitative enzymes)
28
what is hemicellulose
- hterogeneous group of polysaccharide substances
- sugars in backbone, sidechains
- in the backbone (xylose, mannose, galactose)
- arabinose, glucuronic acid, galactose) side chain
- B (1-4) linkages
- makes up cell wall will celulose and lignin
- can be fermented
29
what is lignin
- not a carb
- highly branched poly-phenolic polymer composed of phenol units with strong bonding
- indigestible by mammalian enzymes ; resistant to microbial enzymes
- plant content of lignin increases as plant matures
30
what is pectin
- part of the plant cell wall
- not digestible for mammals
- backbone = a(1-4) linked galacturonic acid units
(sugar = xylose, galactose) side chains
- microbial fermentation
31
what is B glucans
- homo polymers of glucopyranose units with B(1-4) and B(1-3) linkages
- water soluble and highly fermentable
- used commercially as functional fiber
32
how do you combat B glucans in poultry diets and why is it necessary
- because poultry has viscous intensional fluid, it interferes with digestion
- B- glucanase is added to poultry diets containing barely or oats
- without this the nutrients are less digestible
33
what is soluble xylans
- B linked xylose backbone, arabinose side chains ( cause poor digestibiliy in poultry)
- rye, wheat major sources
34
why is xylanase added to poultry diets
- its an enzyme to degrade xylans so it can become viscose
35
what is the difference between dietary and functional fiber
- dietary is the whole plant
- functional is extracted from the plant and bottled
36
what are the physiological effects of fibers
- soluble in water
- water- holding capacity and viscosity ( slows down gastic functions, to feel full for longer and eat less - reduces food intake, energy and fat absorbtion)
- absorbtion or binding ability ( fiber is able to bind to fat = digestibity goes down, reduction in cholesterol absorbtion)
- degradability/ fermentability ( when fermented in the large intestine, promotes growth of beneficial microorganisms = due to slight pH change from VFA prebiotics)
37
what are the basics in carbohydrate digestion in monogastrics
- only monosaccharides can be absorbed from GIT (starch has to be broken down into monosaccharides)
- polysaccharides/ disaccharides are hydrolyzed by digestive enzymes to monosaccharides
- source of carbohydrase activity (all the enzymes in the digestive tract)
- mammalian enzymes can only breakdown a linkages
- principle CH2O fed to monogastrics in starch
38
what are the sources of carbohydrase activity
mouth, pancrease, small intestine epithelial linning ( willi and microvilli)
39
what is the carb breakdown in the mouth
- short residence time in mouth - starch and dextrins are moving on because of limited time
- salivary amylase - can only breakdown a (1-4) linkages
40
what is the carb breakdown in the stomach
- pretty much nothing happens to carbs
- HCL is in stomach
- salivary amylase - deactivated from pH, no carb digestion
41
what is the carb breakdown in the small intestine
- mostly in the first two compartments (duodenum and jejunum)
- amylose, amylopectin and dextrose
- pH neutralized by bicarbonate ions from pancrease = a buffer
- pancreatic alpha amylase - a (1-4) linkages, produces maltose and limits dextrins
- maltose is further degraded by maltose to produce 2 glucose units
- a dextrinase breaks down limit dextrins a 1-6 linkages
42
what are brush border enzymes
- located on villi and microvilli
- contain beta 1-4 linkages
43
what is the absorption of monogastric
- greatest capacity in duodenum and jejunum
- little ileal absorbtion
- very little if any, stomach and large intestine absorbtion
- active and facilitated transport
44
how are monosaccharides transported
- enter portal circulation for transportation to liver (heavily involved in in metabolism, converts to glucose derivative)
- galactose, fructose converted to glucose derivatives via phosphorylation reactions (enter glucose metabolic pathways )
- glucose metabolized by the liver ; largly released into peripheral circulation (muscle adipose mammary glands
- glucose trasnporters
45
what is GLUT1
basic supply of glucose to cells
46
what is GLUT2
low infinity transporter; glucose from enterocyte to blood
47
what is GLUT3
high affinity transporter for brain and other glucose-dependent tissues
48
what is GLUT4
insuline sensative - in muscles and adipose tissues
49
what is GLUT 5
for fructose
50
what is the difference in storage of dipose tissue and skeletal muscle for glucose
adipose - glucose used stored fatty scids synthesized as tryglycerides to fat
skeletal muscels - excess glucose stroed as glycogen
51
during oxidation how many moles of ATP are created
38
52
what do ruminants get from microbes
- VFA's and microbial proteins
- breakdown B linkages
53
what kind of diets do ruminants have
- survive on diets of high fibre that is mostly structured carbs
- fermatative digestion allow extraction of energy from high fibre diets
54
what does a high fibre diet look like
- there is more chewing, so more saliva and amylase is produced
- ferments = cellulose hemecellulose and pectin to produce more
acetate
- this will creat more cellulolytic bacteria
55
what does a high starch diet look like
- more acidic so it will create more amylolytic bacteria producing VFA's propinoate
- ferments amylopectin and amylose,
56
how does the level of feed intake effect VFA production
- the animal that eats more will create more VFA, becasue there is more substrate avaliable - higher proponoate and more amylitic bacteria
- the animal that eats less = higher acetate, less salivia and higher pH = more acetate and celylitic bacteria
57
how does the frequency of feeding effect VFA production
- animal eating once a day = pH goes down = more amylelytic bacteria and propinoate
- smaller amounts of feed = more stable pH which leads to more cellulolitic bacteria and more acetate produced
58
how do the size of the forage particles effect VFA production
- larger food particles = more chewing and salivary amylase = cellulitic = acetate more rumination and higher pH
59
what do buffers do
- more buffering lowers the pH making it less acidic and encouraging cellulolitic bacteria and acetate
60
what does rumensin do
- increases propinoate
61
how can you increase acetate production in rumen
- feed more frequently
- increase amount of dietary forage or roughage
- grind feed more coarsely
- include buffers
62
how can you increase propionate production in rumen
- feed less frequently
- increase amount of concentrate
- grind feed more frequently
- include rumensin
63
what is rumensin
- very common feed additive in beef, dairy diets
- increases gram negative bacteria in rumen / decreases gram positive bacteria
- increases propionate, less methane and increases feed efficiency
- imporves milk production reduces risk of acidoses
64
how are VFAs absorbed
- across the rumen wall into the blood
- passive and facilitative diffusion
- acetate, butyrate metabolized into ketone bodies
65
why are circulating blood (glucose) lower in ruminants than in monogastrics
- monogastrics rely on the glucose from absorbtion of the small intestine
66
what is feedlot bloat
- distension of left flank, abdomen ; causes laboured breathing
- viscous, frothy rumen contents prevent eructation
67
how can you fix bloat
- anti foaming agent
- trochar to puncture rumen
68
what is a dry bloat
- physical blockage
- damage of the vegas nerve - GI tract to the brain
- if there is damage to the brain the animal cant get rid of contractions
69
how do you use a trochar
- inserted into sub-lumbar fossa
- in severe cases
70
what is the difference between using a trochar for froathy bloat and dry bloat
- froathy = cut incision and open with fingers to pour in anti froathing agent
- dry gas bloat = quick release of gas
71
what can cause frothy bloat and why
high grain diets with not enough fibre will cause slimy bacteria
- rapidly growing pasture - alfalfa and clover
72
what are symptoms of Sub acute rumen acidosis
- reduced or erratic feed intake - eat less and less each day
- reduced milk fat test
- reduced rumination
loose manure; undigested grain in feces
poor performance
lameness
