Energy and protein Flashcards
Describe the composition of food
Water
Inorganic dry matter - minerals
Organic dry matter - carbs, lipids, vits, protein etc.
What fractions is feedstuffs broken down in proximate analysis?
Moisture
Ash
Crude protein (CP)
Crude fibre (NDF, ADF, MADF)
Ether extract (EE)
Nitrogen free extractives (NFE)
What is gross energy of feed?
Total energy feed contains
What is digestible energy?
Energy from food animal can access
What is metabolisable energy?
energy available for utilisation by the animal
What is net energy?
the proportion of metabolisable energy that can be used for maintenance, growth, lactogenesis, production of wool/hair, growth of a foetus
What is k factor and what does it mean?
The conversion efficiency of metabolisable energy into net energy
Some energy is lost as heat during digestion and metabolism
k factor = NE/ME
What is heat increment?
the difference betwee metabolisable energy and net energy
What processes lead to production of the heat increment?
Chewing, rumination, digestive motor activity
Production and secretion of digestive juices
Hydrolysis and metabolism of nutrients in lumen and wall of GIT and active transport across
Metabolism of absorbed nutrients and synthesis of macromolecules
What is diet quality/metabolisability?
the proportion of gross energy that is metabolisable
q = ME/GE
What is animal production level (APL)?
how hard the animal is working above maintenance requirements
As production within the animal increases why does efficiency factor decrease?
More food must be eaten => GIT transit time increases => less time to extract available nutrients
Label the metabolisable energy system
What is metabolic rate?
expenditure of energy per given time
What is basal metabolic rate?
energy expenditure for basic life processes at rest
What is fasting metabolic rate?
‘animal’ version of BMR
Usually higher than BMR as movement occurs
What is resting metabolic rate?
amount of energy a non-production animal requires to live without gaining or losing weight
What is field metabolic rate?
Average metabolic rate of an animal
includes energy required to hunt, graze, socially interact, reproduce
How do you calculate metabolic intensity?
Metabolic rate/kg body mass
Metabolic rate tends to be higher in small animals
What is undegraded dietary protein
Protein that escapes digestion in rumen
Dependent on rumen outflow rate and protein source (some proteins more resistant to digestion)
What are the limiting AAs in pigs and poultry?
Pigs - lysine and methionine
Poultry - lysine, methionine, tryptophan
Label the metabolisable protein system
