Chapter 8- Ruminants Flashcards
In ruminants, what are polysaccharides broken down by?
Bacterial enzymes, they are broken down into monosaccharides(glucose)
What are monosaccharides (glucose) broken down by?
Glycolysis, into 3 pyruvate (3C)
what does pyruvate break down into (3C)?
-Acetate (2C) (looses a carbon)
-Propionate (3C)
How do we make Butyrate(4C)?
Its broken down from Acetate(2C)
Where is dietary fibre broken down?
– Slowly digested in the large intestine
* Bacterial enzymes break β1-4 linkages
* Resulting sugars are fermented into VFAs and gas
* The production of VFAs and gas is slower than their removal
What is lactose intolerance ( scientific )
- Lactose intolerance
– Simple disaccharide not digested in small intestine - Lactase hydrolyzes the β1-4 linkage
– Lactose is rapidly fermented in colon - VFAs create osmotic pull and water rushes into colon
- Gas production causes abdominal pain
Explain why Gaterade is so good?
Sports drinks rehydrate the athlete quicker because ….sodium potassium pump, why is generate so great? -hydration + energy, gaterate is providing glucose, she needs to sweat her sweat gland kick outs sodium with water, it evaporates and this energy cools her down
Where is the rumens fermentation chamber?
Large fermentation chamber at front of the GIT
What are most of the diet carbohydrates converted to?
Microbial waste products (VFA’s) which are absorbed by rumen wall
VFA’s= Very short chain fatty acids
What type of environment is the rumen metabolism?
Anaerobic environment
What is diaper rash? why does it happen?
Low pH is irritating the skin around there anus. Dipper rash is when the faeces has VFS’s thats burning babies skin
Name the contents of the rumen?
(4)
*Feed
*Saliva – Increase forage = increased saliva = increase pH – Increased pH = Increase CO2 and CH 4
*Microbes - Bacteria, yeast and protozoa
*Microbial waste products -volatile fatty acids (VFAs)
When a ruminant eats food what is the process
1) Food is first chewed, then enters the rumen.
2) Food passes from the rumen into the reticulum, where it is formed into small portions called ‘cuds’.
3) Cuds are regurgitated into the mouth where they are chewed again – ‘rumination’.
4) These solids are now finely divided and very well mixed with saliva; they are swallowed again, eventually the material enters the abomasum, an organ more like a true stomach, where ‘true’ digestion begins and continues into the small and large intestine
Name the rumen microflora
-Bacteria, Protozoa, Fungi
Whats the bacteria population in the rumen?
*populations: 10^10 to 10^11 /mL – very high
many different bacterial genera highly specialized bacterial community
*all are obligate anaerobes
*specific groups specialize in the degradation of:
cellulose
starch,
hemicellulose
proteins
Name the 5 types of rumen bacteria ?
- Free-living in the liquid phase
- Loosely associated with feed particles
- Firmly adhered to feed particles
- Associated with rumen epithelium
- Attached to surface of protozoa and fungi
Name the two types of bacteria that makes up 75% of rumen bacteria:
-Loosely associated with feed particles
-Firmly adhered to feed particles
Whats the advantage of rumen carbohydrate metabolism?
- Advantage: Can consume worlds most
abundant organic compound (Cellulose) - Repeating glucose units linked by β1-4 bond
– Increase plant digestibility
– Microbes make all of their own amino acids
and vitamins
Whats the disadvantage of rumen carbohydrate metabolism?
– Lose energy as heat and CH4
– Loss of dietary glucose
Whats the process of converting rumen macro-carbohydrate molecules into pyruvate?
- Starch, cellulose, pectins, and hemicellulose are
oxidized to pyruvate
– 1) Bacterial enzymes hydrolyze plant polysaccharides
into monosaccharides
– 2)Monosaccharides are oxidized by glycolysis into
pyruvate
– 3) Pyruvate is converted into VFA’s, CO2 and CH 4
Name the dietary polysaccharides?
-Cellulose, hemicellulose, pectin, starch
What does dietary polysaccharides break down into? and what breaks it down ?
-Soluble sugars
-Hydrolytic species
What are soluable sugars broken down into?
-Intermediary compounds (pyruvate,
lactate, formate, succinate)
Whats another word for microbial growth?
Proliferation
Degradable feed in the rumen is broken down into …. and produce waste products that are known as…
-Rumen Microbes
-CO2, CH4
-VFA
-NH3
-Heat
-Long-chain fatty acids
-H2S
Anaerobic digestion in the rumen :
Glucose (uses) is broken down into 2-5 ATP
-Acetic
-Propionate
-Butyrate (VFA’s)
(Goes into one of these)
*Lactate
-CO2 and CH4
-H2O
-Heat
Aerobic digestion in the rumen:
Glucose + O2 (uses) is broken down into 36-38 ATP
-CO2
-H20
(Doesn’t seem like anaerobic is energetically logical)
Name the 3 energy supply to ruminants: and there %?
-VFA’s (70%)
-Microbial cells (10%)
-Digestible unfermented feed (20%)
How many carbons does each VFA have?
-Acetate- 2 carbons
-Propionate- 3 carbons
-Butyrate- 4 carbons
* All are waste products of microbial
metabolism
* But all are utilized by ruminant animal
What % of dietary carbohydrates are absorbed across the rumen wall?
~70% of dietary calories and 2/3 of total
digestible dry matter of a ruminant are
absorbed across rumen wall
What is the rate of diffusion into epithelial cells?
Rate of diffusion into rumen epithelial cells
varies with rumen pH and VFA chain
length
What does the rumen do with acetate?
It is absorbed through the rumen wall
– Small amount converted to ketone bodies
-Most carried by portal circulation to liver - its converted to acetyl-CoA, 80% escape oxidation and is exported from liver.
Absorbed by extra epatic cells + used for energy via TCA cycle, fatty acid synthesis.
What do the ruminants do with propionate?
- Absorbed through rumen wall
– 2-5% converted to lactic acid by rumen
enterocytes
goes to liver by portal circulation, liver converts propionate into glucose this is called gluconeogenesis . Propionate is the only VFA,s that can be used to make glucose
Whats the ruminant utilisation of butyrate?
- Absorbed through rumen wall
Key fuel for Rumen epithelium converts butyrate into a ketone called beta(B)-hydroxide acid (BHBA) its converted. Travels to portal vein to the liver, the liver doesn’t want it cause its not toxic, BHBA are used by the body to use ATP. Excess BHBA is converted and stored as fat.
Kicked into TCA cycle
important
What has more energy, forages or grains?
-Forage: Less digested
- Lignin limits digestibility of digestible fibre
-Thus less energy extracted from forage than grain
*Forage: Greater energy lost from fermentation
CH 4 & Heat lost during the conversion to acetate
The farmer paid for that carbon
* Forage: Increased rumination
Rumen contractions, a lot of chewing, chewing cud is a muscular activity, energetic cost to chewing. Not as much chewing with a high grain diet.
High forage diet favours fermentation to acetate, high concentrate diet favours fermentation to butyrate
These activities (muscle contractions) cost energy
* Forage: More bulk in digestive tract
Will limit DMI quicker
The animal’s rumen “fills” up and there is now simply not enough space
for more feed intake
High fibre diet fills us the rumen and she simply cant eat anymore.
What type of fermentation does ruminants contain?
-Pre gastric fermentation
Where are carbohydrate feeds fermented?
Fermented in the rumen- end product of fermentation are energy rich molecules (VFA’s) and gases
What does the animal absorb from from fermentation :
1) VFA’s
2) Microbes (Highly digestable)
How are enzymes made in the rumen
?
Enzymes involved in the ruminant are made by the ruminant microbes
What does the rumen absorb?
-Enzymes(organic acids)
-Microbial protein
What do ruminants belch/bloat?
Gas (CO2 and Methane)
What do hindgut absorb?
-Enzymes (organic acid)
Whats the process called when animals eat their own poop?
Capropogy
How much energy is in glucose?
36 ATP
what do hindguts excrete as faeces?
-Microbial protein
-Gas (CO2 and Methane)
Whats the portal system? (portal circulation)
Everything that you eat, from your lip to your liver foes straight to the liver first because if the animal ate something poisonous it will go straight to the liver to detoxify it.
What’s the vast majority of energy used in the ruminants made from?
VFA,s
How does ruminants utilise any of the 3 VFA’s, you need to be able to answer this on an exam:
LAST SLIDE IN LECTURE 8 IS VERY IMPORTANT
Does ruminant animals have amylase?
No 0.
What does high forage diet in a rumen effect in terms of BFA,s production
Total VFA produced = slow, rumen pH=(high)6.5
Highest VFA’s producted = Acetate
What does high concentrate diet in a rumen effect in terms of VFA,s production
Favours the bugs that want to make propionate More digestible, more VFA’s produced production is high, pH is lower (5.5)
What does low rumen pH cause?
Rumen acidosis
Why doesn’t a ruminant animal need pancreatic amylase? Q on exam.
Because it is digested in the rumen and it doesn’t need it cause it doesn’t see it.
