Partitioning-of-Energy-in-Farm-Animals.ppt

Partinoning of energy

1. PARTITIONING OF ENERGY IN
FARM ANIMALS
Lecture No.: 5-7

2. System of energy expression
•Starch Equivalent (SE) -United Kingdom
•The Scandinavian Fodder Unit (SFU) -Denmark
•Fattening Fodder Units (FFU) -Denmark
•The French system of Fodder Equivalent -France
•Rostock NEF system -Germany
•Net Energy of lactation system -Netherlands
•California system -USA
•Total Digestible Nutrients (TDN) -USA
•MetabolisableEnergy (ME) -United Kingdom
•Digestible Energy (DE) -United Kingdom.

3. Introduction
•Lavoisier first demonstrated that oxidation of
nutrients was some form of combustion
•Rubner(1894) first demonstrated that
fundamental Laws of Thermodynamics also
applied to intact living animal systems
•Organic matter processes CO
2+ H
2O +
energy (released)
•Understanding energy transforms is only possible
when it is converted from one form to another

4. Introduction
•Energy goes through many cycles and
transformations, always with loss of heat
•can be released at various rates: gasoline can
exploding vs. compost pile
•nutritional energeticsinvolves the study of the
sources and transformations of energy into new
products (mainly we are concerned with growth
or tissue deposition)
•of all dry matter we consume, 70-90% goes to
synthesis of new products

5. Units of Heat Energy
•The basic unit of energy is the calorie(cal)
•it is the amount of heat required to raise the
temperature of 1g of water 1 degree Celsius
(measured from 14.5 to 15.5
o
C)
•it is such a small unit, that most nutritionists
prefer to use the kcal(or 1,000 calories)
•the kcal is more common (it’s what you read
in the supermarket as Calories)

6. Units of Heat Energy
•BTU(British Thermal Unit) = amount of heat
required to raise 1 lb of water 1
o
F
•international unit: the joule-1.0 joule =
0.239 calories or 1 calorie = 4.184 joule
•a joule(J) is the energy required to accelerate
a mass of 1kg at a speed of 1m/sec a distance
of 1m

7. Partitioning of energy

8. Energy Terms
(total heat production)
•Basic metabolic rate (H
eE):heat energy released from cellular
activity, respiration, blood circulation, etc.
•heat of activity (H
jE):heat produced by muscular activity
(locomotion, maintaining position in water)
•heat of thermal regulation (H
cE):heat produced to maintain body
temp (above zone of thermal neutrality)
•heat of waste formation (H
wE):heat associated with production
of waste products
•specific dynamic action (H
iE):increase in heat production
following consumption of feed (result of metab), varies with
energy content of food, especially protein

9. Gross energy or heat of combustion
•the energy released by burning a sample of feed in
excess oxygen (in bomb calorimeter)-
•dependent on the chemical composition of the feed
but it cannot help predict the energetic transformation
efficiency, viz. gross energy as such is meaningless in
animal production, because it does not take into
account any losses of energy during ingestion,
digestion and metabolism of feed.
•In fact, 1 kg of starch has about the same gross energy
content as one kg of straw even though the energy in
the straw can not be used by pig or poultry due to
missing digestive enzymes.

10. Digestible energy
•DE is the gross energy of feed minus the gross
energy of feces.
•Therefore, this energy system takes into account
the digestibility of feed and gives a useful
measure of the energy the animal may be able to
use.
•it is easy to determine.
•But it does not take into account losses of energy
in urine and as combustible gases and during
metabolism of the feed. These losses vary among
feedstuffs.

12. Metabolizable energy
•ME is defined as the digestible energy minus
energy excreted in urine and as combustible
gases. By taking into account these losses,
metabolizable energy gives a better estimate
of the energy available to the animal.
•ME corrects the digestible energy for some of
the effects of quality and quantity of protein
for example.

13. Net energy
•NE is defined as metabolizableenergy minus the heat
increment, which is the heat produced (and thus energy
used) during digestion of feed, metabolism of nutrients and
excretion of waste.
•The energy left after these losses is the energy actually
used for maintenanceand for production (growth,
gestation, lactation).
•That means that net energy is the only system that
describes the energy that is actually used by the animal.
•the most accurate and unbiased way to date of
characterizing the energy content of feed. However, NE is
much more difficult to determine and more complex than
DE or ME .

14. Total Digestible Nutrient
•TDN (%) = % dig. CP + % dig. NFE + % dig. CF + (% dig. EE x 2.25)
•Relationship between TDN and Digestible Energy (DE)
•1 kg of TDN = 4400 kcal Digestible Energy
= 4.4 kcal/ gram of TDN
•1.87 TDN = 8228 Kcal
•Relationship between TDN and Metabolic Energy (ME)
•I kg of TDN = 3520 kcal ME
= 3.52 kcal / gram of TDN
•Relationship between TDN and Equivalent Starch
•1 kg of TDN = 0.869 starch equivalent

15. Factors Affecting TDN value:
•% of DM in the feed
DM in the feed –TDN Moisture in the feed -TDN
•Digestibility of DM
Digestibility of DM –TDN
•Amount of Fat in the DM
Fat Content -TDN, because % of fat (i.e. EE) is
multiplied with 2.25 in the formula
•Amount of Minerals in the DM
% Contents of minerals (i.e. ash) -TDN

16. Atwater’s Physiological Fuel Value
•Carbohydrate 4.00 kcal /gram
•Fat 9.00 kcal /gram
•Protein 4.00 kcal / gram

17. •Atwater’s Average Gross Energy Value Factors
Carbohydrates 4.15 kcal/g -CHO (DC) 98%
Fat 9.40 kcal/g -Fat (DC) 95%
Protein 5.65 kcal/gram -Protein (DC) 92%

18. Atwater’s Digestible Energy Value
Factors
•Gross energy of carbohydrate = 4.15 kcal
•DC of carbohydrate = 98% = 0.98
•Digestible energy of carbohydrate = gross energy x DC =
4.15 x 0.98 = 4.0 kcal/gram
•Gross energy of fat = 9.4 kcal/gram
•DC of fat = 95% = 0.95
•Digestible energy of fat = gross energy x DC = 9.4 x0.95 =
9.0 kcal/gram
•Gross energy of protein = 5.65 kcal/gram
•DC of protein = 92% = 0.92
•Digestible energy of protein = gross energy x DC = 5.65 x
0.92 = 5.20 kcal/gram

19. Atwater’s Physiological Fuel Value
•Carbohydrates = gross energy x DC = 4.15 x 0.98 =
4.0 kcal/gram
•Fat = gross energy x DC = 9.4 x 0.95 = 9.0
kcal/gram
•Protein = gross energy –excreted energy x DC =
5.65 -1.25 x 0.92 = 4.0 kcal/gram
•Excreted energy: some part of the digestible
energy of protein is excreted in the form of urea,
uric acid and ammonia in mammals, birds and
fishes respectively. Thus in above equation we
subtract 1.25 in terms of EE.

20. Starch Equivalent
1 kg starch equivalent (SE) = 5.082 Mcal DE
= 4.167 Mcal ME
= 1.15 kg TDN
= 1.10 kg DOM
= 2.356 kcal NE

21. •Thanks