Nutrition lecture 4 - Carbohydrates
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In a carbohydrate how many more H are there than oxygen?
Plant tisssues typically have _____ carbs while animals have ____ carbs
Instead of carbs animals store energy as?
Why dont we want to use protein for our energy?
Because ti is expensive and carbs are quich and cheap
Are triose and tetrose carbs important? Where do we find them?
- usually biological accident
What are the 3 important pentose carbs?
Pentose carbs are often used for what?
Structural building blocks
What is the most important length of carbohydrate in terms of nutrition?
6 carbons or a hexose
Why did they used to call glucose dextrose?
Cause it was dextro rotary was the first molecule to reflect light tot the right
2 places we see energy stored as glucose?
Honey and grapes
What is inulin?
Polymer of fructose
2 components of lactose?
Galactose and glucose
Do most animals have enszymes to break down sucrose? What happens if you feed to baby piglets?
- Just feeding bacteria, can cause cramps and diarhea
Mammalian enzymes break down?
Bacteria break down?
Maltose has what type of bond? What about isomaltose?
Amyloses structure is? While amylopectin is?
What type of feeds do we see glycogen in?
Only animal feeds like fish and meat meal
Do we see glycogen in plant tissues?
Cellulose is a polymer of?
Hemicellulose is a polymer of?
In NDF what is included?
Cellulose, hemicellulose and lignin
In ADF what is included?
Cellulose and lignin
Phenyl propane mess
Can anyone break down lignin?
3 places in a monogastric we see carb digestion come from?
- Intestinal brush border
In the intestine the general rule of thumb is the farther forward the more? and the farther backwards the more?
What form do sugars have to be in to be absorbed?
3 FA used by ruminants?
3 elements in carbs?
C, H, O
Are all cabrs highly digestible?
- it includes starches, sugars and fibrous constituents
2 forms of animal carbs?
Glycogen and glucose
In plants the insoluble carbs do what?
Where can we find trioses and tetroses?
Intermediaries in TCA cycle etc
function of ribose? (4)
- Component of genetic material RNA
- Component of ATP
- Componenet of NADH
- component of riboflavin
Component of genetic material DNA
When ribose is bound with adenine what is formed?
What is the function of riboflavin?
- Transfer of electrons in oxidation and reduction reactions
- transformation of folic acid and pyridoxine into active forms
- Conversion of tryptophan to niacin
3 pentose sugars we discussed?
- Ribose and deoxyribose
Where do we find xylose?
what is the main function of xylose?
component of anti nutritional factor in rye and wheat called soluble pentosans (along with arabinose)
Where do we find arabinose?
GUms and pectins
What industry is arabinose growing in?
Canola crushing industry cause being added back to meal
What are the 3 main hexoses we discusssed?
How is glucose commercially produced today?
Hydrolysis of corn starch
What is the major end product of carb digestion in monogastrics?
4 functions of galactose?
- Part of lactose
- Occurs in galactosides in NS
- Component of galactolipids in plant leaves
- Component of raffinose and stachylose which are principle carbs in soybeans
What is the sweetest of the natural sugars?
Where is fructose found?
Fruits and honey
Inulin is a polysaccharide of?
Is aspartame sweet?
200x more than table sugar
3 main reactants used in synthesis of aspartame are?
- Aspartic acid
4 main dissacharides we discusssed?
Sucrose is composed of?
Glucose and fructose
Main places we find sucrose?
Sugar cane and sugar beet
Maltose is made up of?
2 glucose molecules
Maltose is often seen as a?
Intermediate in starch and glycogen breakdown
Maltose is famously used in the production of?
Lactose is found?
ONly in milk
Lactose is made of?
Glucose and galactose
What is cellobiose?
2 molecules of beta linked glucose
How is cellobiose related to cellulose? How is it broken down?
- Basic repeating unit of cellulose
- cellulase in microbial fermentation
What is stachyose? What is it made of?Where is it found? What is it known for?
- It is an oligosaccharide
- 2 galactose 1 glucose and 1 fructose sequentially linked
- Soy beans
- Undigestible, causes flatuence and abdominal discomfort, recent research shows may be probiotic
What are polysaccharides? Are they water soluble?
- high molecular weight
- hundreds of thousands of sugar molecules
What is the most important carbs to animal feeding?
Starch is used for what in plants?
To reserve energy
2 types of starch granules
- Soluble in water
- Long unbranched chains of glucose
- 20-30% starch in most plants
Both amylose and amylopectin use what bond?
Amylopectin differs from amylose via?
- Contains alpha 1,6 branch points
- 70-80% of starch
What enzyme does amylopectin require for digestions?
alpha 1,6 glucosidase
Describe gelatinization? Where is it used mostly? For what stage of animal? often used in conjunction with?
- application of moist heat allowing rupture of starch granules
- potatoe starch
- Young animals mostly pigs and chickens
- extruders and expanders
7 polysaccharides we discussed?
- beta glucan
- Soluble pentosans or xylans
Glycogen structure is similar to?
Glycogen side chains are what compared to amylopectin?
Cellulose is found in?
Is cellulose water soluble?
Cellulose structure resembles closely? BUt is different in that?
hemicellulose is found? compare its degradation to cellulose? As the amount in the diet increases what happens?
- In plant cell walls
- Less resistant to degradation
- Higher percentage intake goes down
What can you use to calculate hemicellulose?
NDF - ADF
where do we find lignin?
Fills space in plant cell wall between other structural componwenets
what happens to lignin as plant matures?
INcreases in amount
Where do we find beta glucans? Describe them
- Bran of cereal grains such as barley oats rye and wheat
- Linnear unbranched polysaccharides beta 1,3 and 1,4 polysaccharides of glucose units
Why is the beta 1,3 bond of the beta glucan important?
Increases solubility and allows it to cause viscous digesta and interfere with digestion especially in poultry
Beta glucans are broken down by?
Where do we find pentosans and xylans? What do they do? broken down by? describe its structure
- Rye and wheat
- cause poor digestion in poultry
- beta linked xylose backbone with arabinose side chains
3 componenets to carbohydrate use?
Can dissacharides be absorbed in the GI tract?
NO only monosaccharides except in the case of newborns
3 sources of carbohydrase activity?
- Salivary glands
- Epitheleal lining of small intestine
Mammalian enzymes only have the capacity to break down?
The prinicple carb fed to monogastric animals is?
While the salivary amylase breaks down? Which makes starch go to? It is not very effective because?
- alpha 1 4 linkages
- dextrins, maltose, and glucose
- Short period of residence in mouth
why is the little to no carb digestion in the stomach?
pH is too low for any carbohydrase activity
What is the principle site of carb digestion? Principle enzyme? This digestion is a how many step process? What are the steps?
- Small intestine
- Pancreatic amylase
- breakdown to diassachardies and break down to mono's
While starch and amylose are broken down to maltose as their dissacharide what is amylopectin broken down to? Will this substance yield a difference in monosaccharides yielded?
- isomaltose + maltose
- no it will still yield 2 glucose when broken down at brush border
Where is the principle site for dissacharide breakdown
Sucrose breaks down into?
Glucose + fructose
Which section of the small intestine has the greatest capacity to absorb carbohydrates?
Duodenum and jejunum or more cranial aspects
Do the stomach and large intestine absorb any carbohydrate?
What are the 2 mechanisms of carb absorbtion?
- Passive diffusion
- Active transport (may involve specific carrier protein and definitely involves energy)
What are 3 factors affecting the ability for carbohydrates to be absorbed?
- D configuration only, L config is not absorbed
- Need a hydroxyl group on C2 in the down position
- Need a methyl or substitute methyl on C5
What is done with the carbs we break down and absorb?
- Immediate source of energy for ATP or glycolysis
- Glycogen precursor
- Fat synthesis
Bacteria in rumen allow ruminants to break down?
beta linkages in high forage feedstuffs such as silage
In ruminants what types of carbs are broken down to glucose in the rumen? What is this glucose used for? How does the ruminant get anything out of this?
- ALL of them litterally everything
- Bacterial growth and proliferation
- Ruminant digests the bacteria
Ruminant uses what as a primary energy source? It gets this as a byproduct of?>
What are the 3 VFAs from carb fermentation
What is the most common VFA produced during carb fermentation
Acetate has how many carbons
Acetate is primarily formed through the feeding of which feedstuff comparatively
What happens to acetate in the ruminant (IE where does it go) (2)
- Metabolized through the TCA to produce 24 ATP
- Can be used for fat synthesis (acetyl coa and then malonyl coa)
Butyrate has how many carbons?
Butyrate is generally at what kind fo proportional levels comapared to other VFAs?
Propionic acid (propionate) is how many carbons?
Levels of propionate increase in animal with what type of feed fed to the animal?
What is important about propionate?
Can be used to form glucose
Fermentation of acetate produces how many H? What about butyrate? Propionate?Why can all this H be bad for the animal? What are 2 ways it gets rid of this?
- Lactic acidosis
- Add to unsaturated fatty acids
- Produce methane gas
What is the most energetically favorable VFA? Why would we want acetate in some situations?
- Presurcor to fat synth so in a dairy situation need milk fat
In general how does pH effect VFA production
- Lower pH favors propionate
- Higher pH favors acetate
5 factors effecting relative proportion of VFAs? Use some of these to increase acetate production (4). Do the same with propionate (4)
- Feed intake
- Frequency of feeding
- protportions of starch and fiber
- Size of forage particles
- Presence of rumen modifiers
- Feed more frequently
- increase roughage
- grind more coarsley
- include buffers
- feed less frequently
- increase concentrate
- gind feed finely
- include rumensin
Name 2 carbohydrate related nutritional disease
- Feedlot bloat
- lactic acidosis
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