Intro Flashcards
What is nutrition?
qualitative & quantitative needs from the diet to maintain good health or production (contains all essential nutrient & balanced macro- & micronutrients)
What are macronutrients?
Carbs, protein, & fat
What are micronutrients?
vitamins & minerals
What is a nutrient?
any chemical compound that is needed from a diet to maintain life & good health
What is food?
Edible material that provides nutrients (used for humans & small animals)
What is feed?
formulated whole diets for non-humans
What are proximate analyses?
analytical methods to assess feedstuffs
What are feedstuffs made up of?
- moisture
- dry matter: organic material (protein, fat, carbs, & vitamins) & inorganic or ‘ash’ material (minerals)
What happens to organic substrates (fat, protein, carbs, etc.) in animals?
they are oxidized to CO2 & H2O through a series of enzyme catalyzed reactions producing ATP
How much ATP does the average marathon race take?
20kg of ATP
What are energy substrates and what is important about them?
- carbs, lipids, and amino acids
- they can be used for energy production are mostly interchangeable & not actually individually required by the animal
What is a kilocalorie?
the energy required to raise the temperature of 1 kg of water 1 C (the Calorie (capital C) used in human nutrition is actually a kcal)
What is a Joule?
used in Europe & Scientific publications (1 calorie = 4.18 joules)
What are the 2 general approaches to describing the energy content of food/feed?
- energy partitioning
- nutrient-ATP based-modelling
What is energy partitioning?
we burn the food (oxidize it) & measure how much heat it gives off
What does bomb calorimetry measure?
the gross energy of a feedstuff
What is GE?
Gross Energy
- the heat of combustion released when carbohydrates, lipids, and proteins in feedstuff are burned off & completely oxidized in a bomb calorimeter
Feed + O2 =?
CO2 + H2O + HEAT
How does a bomb calorimeter work?
- material is combusted (burnt) inside it
- box is sealed w/ an oxygen atmosphere
- burnt material heats up the water
- energy change is found from temp change of water
- change in H = change in E + (P)(change in V), where volume is constant but pressure changes, can calculate change in E
What are the limitations of GE?
Gross Energy indicates very little about the actual nutritional value of a feed to an animal. Need to account for losses of energy.
How do we account for losses of energy?
look at poo!
What is FE?
Fecal Energy
- some feed energy is not absorbed & is lost in the feces due to incomplete ingestion
- fecal energy is the energy contained in feces & is measured using a bomb calorimeter
- feces is the single largest loss of ingested energy
What is DE?
Digestible Energy
= GE - FE
How do you calculate digestibility?
(DE/GE) x 100%
