1 – Nutrition Intro

Question 1

Nutrition definition

Answer 1

• Qualitative and quantitative needs from the diet to maintain good health and production
  o Contains ALL essential nutrient
  o Balanced macro- and micronutrients

Question 2

Nutrient definition

Answer 2

• Any chemical compound that is needed from diet to maintain life and good health

Question 3

Food definition

Answer 3

• Edible material that provides nutrients
  o Used for humans and small animals

Question 4

Feed definition

Answer 4

• Formulated whole diets for non-humans

Question 5

What is proximate analyses?

Answer 5

• Analytical methods to assess feedstuffs
• 1. Moisture
• 2. Dry matter

Question 6

What does dry matter all consist of?

Answer 6

• Organic material
  o Protein, fat, CHO, vitamins
• Inorganic or ‘ash’ material
  o Minerals

Question 7

Dry matter analysis: ‘procedures’

Answer 7

• Use nitrogen to measure protein=crude protein
• Ether extraction to determine fat
  o Boil in acid; boil in alkali to get crude fiber and ash
  o Burn to get ash and crude fiber

Question 8

What are the 3 ‘main’ energy substrates?

Answer 8

• CHO
• Lipids
• AA

Question 9

What is a kilocalorie?

Answer 9

• Energy required to raise the temperature of 1kg of water 1 degree C
• (joule is used in Europe, 1 calorie=4.18J)

Question 10

What are 2 general approaches to describe energy content of food/feed?

Answer 10

• Energy partitioning
• Nutrient ATP based modelling

Question 11

What do you need to consider with energy partitioning?

Answer 11

• How much energy is there in food?
• How much is available to the animal for biological processes?
• How can we measure it?

Question 12

How do you measure the energy in grain?

Answer 12

• Oxidize it (burn) and measure how much heat it gives off

Question 13

What is bomb calorimetry?

Answer 13

• Measures the GROSS ENERGY OF A FEEDSTUFF
• GE (gross energy) is heat release when CHO, lipids, and proteins are burned-off
• Feed + O2 = CO2 + H2O + heat

Question 14

What are the steps of bomb calorimetry?

Answer 14

• Material is combusted inside a bomb calorimeter
• Box is sealed with O2 atmosphere
• Burnt material heats the water
• Energy change is found from temperature change of water
• *constant volume, not constant pressure, so gives off E

Question 15

What is GE?

Answer 15

• Amount of heat released when a substance is completely oxidized in a bomb calorimeter
• GE=heat of combustion

Question 16

What are the different energy values/ranking of feeds? (kcal/g)

Answer 16

• Fat: 9.3
• Protein: 5.65
• CHO: 4.30

Question 17

What are the limitations with GE?

Answer 17

• Indicates very little about nutritional value of a feed to an animal
• Ex. corn: 4.4kcal/g vs. wood 4.5kcal/g
  o Would not consider wood to be a nutritious feed ingredient
• **need to account for losses of energy

Question 18

What is fecal energy (FE)?

Answer 18

• Some feed energy is NOT absorbed, but lost in the feces due to INCOMPLETE digestion
• *energy contained in feces measured using a bomb calorimeter
• **single largest loss of ingested energy

Question 19

What is digestible energy (DE)?

Answer 19

• DE=GE-FE
• *widely used in pigs and finfish

Question 20

What is the equation for digestibility?

Answer 20

• (DE/GE) x 100

Question 21

What does feces all contain?

Answer 21

• Water
• Unabsorbed feed dry matter
• Bacteria (~10^11 bacteria/g)
• Sloughed gut epithelial cells
• Digestive enzymes