A11 Flashcards
What is fermentation of carbohydrates?
It is the process where rumen microroganisms is used to produce energy
What breaks down the carbohydrates?
Microbes
what does the microbes in the rumen include?
Bacteria, fungi and protozooa
What does the microbes feed on?
The forages ingested by the cow
How are the carbohydrates fermented?
The microbes break the carbohydrates down to simpler sugars. These sugars are used as an energy source for growth and to make the end product
What is the end product of carbohydrate fermentation?
VAF = Volatile Fatty Acid¨
What is VAF?
The primary energy source of ruminants
What is the optimal pH in the rumen?
6.2-6.8
What happens if the pH is decreased?
Less than 6. fibre-digesting bacteria die out, lactic acid bacteria increase, and acidosis results
How does saliva play a role?
It acts as a buffer. The saliva will improve the rumination capacity and the activity of the bacterias will be much better.
How much saliva is produced?
20L/day
How much of the energy supply is based on the VFAs?
70-80%
Name the major Volatile Fatty Acids produced:
- acetate (or acetic acid)
- propionate (or propionic acid)
- butyrate (or butyric acid)
How are the VFA absorbed?
through the walls of the rumen and are then
transported in the blood to the liver. In the liver they are converted to other sources of
energy. From the liver, the energy produced is used to perform various functions
- Milk production
- Pregnancy
- Growht
etc
Name the main composition and types of carb in plants
Non-structural and structural carbs
Name some non structural carbs
Starch and sugar
Name some structural carbs
Hay/roughage, pectin, cellulose, hemicellulose, lignin
What is the main goal of fermentation of carbohydrates?
To produce pyruvate from carbohydrates, such as sugar, starch, cellulose etc to the volatile fatty acids - Energy source
What does the bacteria produce in the rumen?
Extracellular enzymez, which break down the polysaccharides down to pyruvic acid
What happens to the produced pyruvic acid?
Enters into 4 different pathways and is then broken down by the INTRACELLULAR ENZYMES to produce either VFA or ATP
How much Volatile Fatty Acids i produced per day?
3-5kg/day
What happens if the starch concentrate decreases and the hay content increases?
Acetic acid levels increase and propionic levles decreases
increased fibre = ?
increased lactic acid
increased starch =?
increased propionic levels
What happens if the formic acid is conversed into methane?
Significant energy loss, up to 8-10%
