Domesticated animals (حیوانات اهلی)
Human food (غذای انسان)
sport (ورزش)
Draught power (شخم زدن)
Provider of manure (تولید کود)
Savings bank(سرمایه)
Social status (منزلت اجتماعی)


Widely roles, availability and quality of feeds = Different Strategies
Production of foods (تولید غذا) main purpose :
Safe (ایمن)
Efficient production (بازدهی )
Minimum cost(حداقل قیمت)



Different feeding strategies:
Animal species (ruminants, monogastrics)
Nature of production (meat, wool, manure, draught)
Required intensity of production (feedlot, free ranging)
Environmental factors (temperature, soil fertility, intensity of fertilisation)


Aim of animal nutrition is to quantify the requirement of animals:
Physiological status
Quantifying the feeding values of feedstuffs (chemical and physical properties)


Compose diets:
Meet the requirements of the animals
No negative effects on animals and consumers’ health
Improve the quality of the animal product
Results in a minimum excretion of environmentally polluting compounds


Nutrients, chemical element or compound that supports:
Normal reproduction
Growth
Lactation
Maintenance of life processes


Nutrients:
Fats
Proteins and amino acids
Vitamins
Minerals
Nutrients are needed as the substrates for all physiological processes



Essential nutrients:
Cannot be synthesised by the body
To compose the adequate diets: We have to know the nutrient requirement:
Maintenance
Production


Maintenance requirements:
Maintaining body weight and composition
Maintaining physiological balances
Normal activities of organs and tissues for these purposes
Maintaining body temperature
Activities such as moving, eating, chewing, standing etc.


Requirements for production:
Reproduction
Growth
Milk production
Egg production
Wool or fur production
Draught power



Diets or supplemental feeds have to be formulated:
Adequate and balanced levels of nutrients
At reasonable cost
For the desired purposes
Appetising (to ensure an adequate intake)



Feed evaluation:
The value of a feeds:
Chemical composition
Digestibility and nutrient utilisation
Feedstuff evaluation systems:
Additives (Feeding value of a diet should equal the sum of the different components)
Reliable (Giving the feeding value as accurate as possible)
Easy to determine (determination methods should be easy and fast)




Feeding value:
The net value for the animal
The net contribution of the feedstuffs to maintenance and production requirements
Characteristics having a positive or negative effect :
On the animal
End products




Feed evaluation criteria:
Simple analysis is not available
Not additive
A few feed characteristics are determined
Energy values
Digestible amino acids etc.



The aim of this course:
Basic knowledge
To compose appropriate diets
To develop appropriate feeding strategies






FEEDS: مواد خوراکی

Analysis and Composition
Digestibility and Utilisation

Why feedstuffs are needed:
Maintenance
Reproduction
Production (milk, eggs, meat, wool etc.)
Work
manure



Why feedstuffs are needed:
To provide energy
To provide precursors for synthesis of animal components such as proteins etc.



Why feedstuffs are needed:
To provide energy
To provide precursors for synthesis of animal components such as proteins etc.




An important characteristics of feedstuffs:
The amount that animal will consume it:
Palatability
Physiological status of animal
Chemical composition




To get more insight about the value of feeds:
Chemical analysis of nutrient composition
100 years ago:
Weende experimental analysis or proximate analysis




Feedstuff

Moisture


Dry matter (DM)
1-Inorganic matter
(crude ash)



2-Organic matter
(OM):

N-containing matter
(crude protein or CP)

N-free matter Ether extract
(crude fat or EE)
N- free extractives
(NFE)
Crude fibre
(CF)

Sampling (representative sample) :
Small quantities from different places
Samples have to be dried (Chopping, Cutting)
Grinding the samples (over a 1 mm sieve)
Storing the sample in a tightly closed container or even refrigerated.



Energy:
Gross energy
Heat produced during the combustion in calorimetric bomb
1 g of sample



Pressurised oxygen (30 atmosphere)
Rising the temperature of surrounding water



Water:
Drying in 100-105° c until constant weight
Sensitive feeds
Drying at lower temperature (60 or 70° c) under vacuum (proteins)
Freeze-drying
Toluene distillation (silage)



Inorganic matter (ash):
Contains a wide variety of minerals (oxide, carbonates and sulphates)
Losses may occur due to volatilisation

22 mineral elements are essential:
Macro-nutrient elements (7; Ca, P, K, Na, Cl, Mg and S)
Micro-nutrient elements (15; Fe, I, Zn, Cu, Mn, Co, Mo, Se, Cr, Sn, V, Si, Ni, As, F)




Carbohydrates:
Proximate analysis gives a rather poor description of feeds
CF is chemically not well defined
Structural carbohydrates has a big influence on digestibility of plant materials:
Developing some analytical methods
CF was designed to include the material of feeds which are low in digestibility


CF is included:
Bulk of cellulose
Part of hemi-cellulose
Lignin


Feed Sample

Extracting with diluted sulphuric acid (0.15mol/l)

Extracting with diluted sodium hydroxide(1.5 mol/l)


Drying and incinerating, The remainder of CHO is NFE


NFE= OM – (CF+ CFat + CP)





CF does not give an accurate enough of structural CHO:
New analytical technique was developed (Van Soest ,1970)
NDF (Neutral detergent fibre), mild extraction of sample with NDS: Cellulose, Hemi-cellulose, lignin
Sodium-laurylsulphate, Sodium tetra borate, di-sodium hydrogen phosphate, EDTA, NaOH, 2 ethoxy-ethanol
ADF (Acid detergent fibre): Cellulose, Lignin
H2SO4, N-cetyl-N, N, N-trimethylammoniumbromide
NDF – ADF = Hemi-cellulose





The analytical methods presently in used are inadequate
The average recovery of anhydrous monomers (HPLC) is far below 100% of what can be expected on the basis of cell wall analysis





Alternative methods (Englyst, 1989)
Cell walls + Oligosaccharides = Non-starch polysaccharides = Total anhydrous monomers released from NSP after Hydrolysis
GLC (gas-liquid chromatography), HPLC (high performance liquid chromatography)




Proteins
Complex organic compounds of high molecular weight
Contains C, H, O, N and S
Vary widely in chemical composition, physical properties ( i.e. solubility), size, shape and biological function
Present as cell membranes, enzymes, supportive tissues, blood plasma proteins, hormones and immune antibodies






Proteins
Protein content = N × 6.25 (proteins usually contain on average 16 % N)
N content is determined by kjeldahl procedure

Feed sample

Digestion by concentrated sulphuric acid
Ammoniacal N in ammonium sulphate
Adding concentrated sodium hydroxide
Ammoniacal N in ammonium sulphate
Ammonium hydroxide (titration with an standard acid)




Lipids
Organic material can be extracted from feeds by solvents (di-ethyl-ether or hexan)
Crude fat:
major part consist of triglycerides or pure fat
Waxes, phospholipids, fat-soluble vitamins, carotene etc.


Classification of feedstuffs
Depending on nutrient concentration in the DM:
Roughage
concentrate
Roughage: contains > 18% CF, provide less nutrients compare to concentrates
Roughages are fed as :
Fresh plant (e.g. grass)
Conserved form (grass silage, corn silage, grass hay)



Classification of feedstuffs
Concentrates:
Plant origin; grains or seeds (by-products of human food industries)
Animal origin (slaughter offal, milk products)
Contain no CF
Contain low quantities of CHO (less than 1%) except milk products



Other properties of feedstuffs
Feeding value:
Concentration of nutrients
Other properties (voluntary feed intake):
Animal factors (species, body weight and type and level of production)
Dietary factors (volume, smell, taste and texture)



Feed intake:
Most animal do not like the bitter taste
Contaminated feeds (Sand, manure or moulded feeds)
Intake of a diet with a high volume (high cell wall level):
The volume of gut
The digestibility of the cell walls
The rate of digestion




Feed intake:
The number of taste buds for some animal species

Chickens 24
Ducks 200
Dogs 1700
Humans 9000
Pigs and Goats 15000
Rabbits 17000
Calves 25000
Catfish 4400




Feed intake:
Poultry
have very poorly developed taste and smell organs
Poultry does require a certain texture of the feeds
Fish
Taste buds present outside the mouth (gills, head surface, fins and barbels)





Ruminants
Require a certain amount of structure in the
Ratio between slow and fast degradable parts of the diet (ratio between the fibre and the fast degradable carbohydrates)
Stability of rumen environment
Optimal rumen fermentation
For the other animal species a certain level of cell wall has a positive effect on degradation and passage of feed through the gut
Cell wall materials stimulate intestinal peristalsis






Digestibility:
The fraction of the ingested feed not excreted with the faeces is per definition digested
Determine at fixed level of intake
Presence of anti-nutritional factors (ANFs)
The efficiency of utilisation of digested ingredients determines the nutritive value of a feedstuff
Term digested and absorbed
Digestion: degradation of feed components in the lumen of the gut
Absorption: Uptake of the degraded component by the gut wall





Digestibility:
Digestion
Physical
Chemical
Hydrolytic enzymes:
Animal itself
micro-organisms





Digestibility:
Ruminants:
Microbial fermentation in the forestomachs
Bacteria, protozoa and fungi
Enzymatic digestion in the small intestine
Microbial fermentation in the large intestine




Digestibility:
Mono-gastrics:
Enzymatic hydrolysis in the stomach and small intestine
Microbial fermentation in the large intestine (horses and rabbits)

Digestibility:
Animal characteristics (species and age)
environmental condition