Lecture 18- Bioenergetics Flashcards
What is bioenergetics?
The study of energy supply , utilisation and dissipation in animals
What is the definition for energy?
This is the capacity for performing work.
What do nutrients contain?
How is this yielded in the body?
What is this * used for?
-Chemical energy
-Yielded upon chemical breakdown
-Used in the body to perform chemical, mechanical, electrical or osmotic work.
What is the efficiency of conversion of chemical energy to work ?
Its less than 25%, the remaining 75% is converted to thermal energy (heat)
What are the measurements for energy?
-Joule
-Calorie
How many joules is in 1 calorie?
1 calorie = 4.184 J
How many calories are in 1 kcal
1000 calories
What piece of equipment is used to measure the amount of energy in something?
Bomb Calorimeter
What nutrient produces the most heat?
1- Lipids
2- Protein
3- Carbohydrates
How much energy is ingested in :
1- Carbohydrates
2- Proteins
3- Fat
4- Alcohol
- 4kcal/g carbohydrate
- 4kcal/g protein
- 9kcal/g fat
- 7kcal/g alcohol
What are the potential consequences of ingested energy?
1- Converted to chemical energy. (Oxidation of glucose into 38 ATP for “work”
2- Stored (glycogen, adipose tissue, muscle)
3- Excreted
4- Liberated as heat (most)
Whats the Energy Balance Equation?
Energy in = Energy out + Energy to stores.
Can energy be created or destroyed?
NOOOOO
What does BMR stand for and explain it:
Basic Metabolic Rate:
Amount of energy used by a fasted animals resting in a natural environment (Same as the amount of heat produced )
What is BMR the same as?
RMR :
Resting Metabolic Rate
What is Maintenance Energy Requirement ?
and what is it usually?
The amount of dietary energy required to maintain a constant body weight.
Usually 1.5-2x that of BMR
What is body weight exponentially related to?
Surface area -
thus energy requirements are frequently described on an metabolic body
weight (BW 0.75)
What is a positive energy balance?
Energy in is greater than energy out (weight gain)
What is a negative energy balance?
Energy out is greater than the energy in (weight loss)
What is an energy equilibrium?
Energy out is the same as the energy in (weight manintance)
What is GE?
What is used to find this?
Is this accurate way of gathering data?
-Gross energy= Total energy content of feed.
-Bomb calorimeter- Energy released as heat
when a feed if completely oxidized to CO2 and H2O
-Provides little information on nutrient utilisation.
What does feed intake provide functions for in the body?
-Maintenance
-Growth
-Work
-Lactation
-Gestation
What is FE?
What are the 2 sources of this?
Faecal Energy
This is the largest energy loss.
1-Undigested food
Indigestible
Increased rate of passage
2-Endogenous
Active secretion
Cells slough
Undigested microbes and their metabolites
What is DE?
Whats another name for this?
What does this provide?
Digestible energy = Gross energy-Fecal energy.
Apparent digestibility.
It provides some assessment of biological value.
What is the digestible energy losses
For ruminant animals?
For horses?
For pigs?
-40-50% for roughages, 20-30% for grains
-35-40%
-20%
What does the total gross energy in urine like?
-Whats it called in mammals
-Whats it called in birds
-Whats the gross energy for pigs?
-Whats the gross energy for cattle?
Loss is stable (influenced by diet)
-Urea in mammals
-Uric acid in birds
-2-3% for pigs
-4-5% for cattle
Whats the main form of gas thats lost?
Methane (CH4)
Name the animal that the greatest gaseous losses are in:
Ruminants (82% DE)
What loss is so small that its not considered for ME?
Gaseous losses (>95% of DE)
What is Metabolic Energy? (ME)
Is this ME more or less accurate than DE?
ME=
DE-Gas and urine energy
More accurate
(Can be calculated from DE)
What sort of energy is used in swine and poultry industries and also human nutrition ?
ME (Metabolic Energy)
Ruminants ME =
Nonruminants ME=
Ruminants= 82% of DE
Nonruminants= >95% of DE
Name the 2 Retained energy:
1- Net Energy Gain
2- Net Energy Intake(Lactation)
What % of gross intake can heat increment be?
25-40% (2nd largest energy loss)
Whats the lowest HI? for what nutrient
For fat
Whats the highest HI? for what nutrient
For fibre
How are there losses of energy as heat?
Basal metabolism
Muscular activity
Digestion and absorption
Microbial fermentation
Product formation
Waste formation and
excretion
Thermal regulation
What is left after accounting for losses to
feces, urine & gasses and heat increment?
Net Energy
Where is the only place we loose heat through out body?
Through our skin
Whats is Heat Increment?
It is the energy just in fermentation and in metabolic process
List the different Net Energies?
1- NEm
2- NEg
3- NEl
(Maintance, gain, lactation)
Whats the best indication of energy available for maintance and production:
Whats it especially used in what industries?
Net energy
Beef, Dairy, Sheep
Can you assign a simple NE value to a feedstuff?
Its not possible to assign a single NE value to a feedstuff
Learn the diagram off
What are factors that effect BMR?
- Height, weight and surface area
- Age
- Gender
- Physiological state
- Body Composition (confounded with age and gender)
- Emotional state
Whats expensive to maintain in the body?
Muscle, constant protein turnover.
Typical weight loss involving reduced caloric intake results in the loss of fat and muscle … whats the %?
-70% (fat)
-30% (muscle)
Why does an animal nearly always regain the weight as adipose tissue?
After an animal looses weight, they require
fewer calories but frequently don’t alter diet regimen. As a consequence they almost always regain the weight as
adipose tissue.
What type of energy is involved in net energy?
-Maintenance (NEm)
-Retained energy (RE)
Whats the defination for maintenance energy ?
Its the amount of dietary energy (protein) needed to maintain an animal in zero energy (nitrogen) balance.
List the 3 maintenance energy requirements:
1-Basal metabolism
2-Muscular work
3-Temperature regulation
Whats basal metabolism affected by?
Body size
Hes gonna ask about the bomb in the exam so know it
What do small animals have and increased ________ ratio and consequently a larger________ ________ ________ to the environment per unit time.
-Surface-to-volume
-Relative heat loss
How must an animal maintain a constant high body temperature?
A small animal must oxidise food at a high rate.
Why do snakes coil to stay warm?
To reduce their surface area
On the back of a feed what type of calories are they talking about ?
ME (Metabolism Energy)
Whats the goal for an anima?
to maintain constant internal temperature
If im feeding broccoli to my dog instead of steak why is DE and ME different
The animal cant digest it as its high is structural carbs so he farts it out.
What is heat increment
Body temp goes up after eating a meal. He starts to sweat because its taking energy to eat the meal.
(fermentation generates enormous amount of heat)
Whats the equation (symbol for metabolic body weight)
W0.75
Who looses more energy, ruminants or monogastric?
Ruminants , especially going from DE to ME
Do puppies or dogs have a higher energy requirement?
Animal requires a dense nutrient and digestible diet than adult energy
What does decreased ambient temperature increase?
Increases metabolic rate because the animal HAS to maintain healthy body temperature
