Lecture 2 Flashcards
Define digestibility?
The portion of a feed not excreted in the feces which is therefore assumed to be absorbed
What is the single most important determinant of nutrient availability?
Digestibiilty
In lamans terms explain digestibiliyt
a lump of coal will release energy in a bomb calorimeter, but yields no available energy to animal
5 ways to measure digestibility in vitro
Regression Using Chemical analysis
Artififical rumen
Gas Productioin
Enzymes
Nylon Bag
Total Fecal collection
Determin How much nutrient is in feed
Determine how much nutrient is in feces
Express the difference as a percent of nutrient intake
Apparent vs True Digestibiilty
it is assumed that all of the components in the feces come from feed, however, it should be noted that there are exogenous sources
3 examples of endogenous secretions
Digestive secretions
Dead bacteria
Sloughed-off intestinal cells
2 problems with total collection?
Feed wastage can occur
Must collect all feces
- diarrhea causes problems
What is the indicator method?
Mix an indigestible indicator into feed stuff at a known concentration
Collect one sample of feces and measure concentration of indicator in feces
5 Properties of ideal marker
Cannot be digested
No metabolic effect
Stable
Inexpensive
Easily detected
How do pig researchers use the nylon bag technique?
Mimic digestion in the stomach by incubating bags in pepsin and HCl and then insert bags into duodenum
