Protein in Animal Feeding

Organic compounds made up of amino acids

Contain: carbon, hydrogen, oxygen, and nitrogen. Some may contain sulphur, phosphorus, and iron

Supply materials to build body tissue (ligaments, hair, hooves, skin, organs, and muscle are partially formed by protein)

Protein in animal production

Is the largest and most costly part of the ration

Is limited available As essential nutrients Is most deficient nutrient Excess intake, economically and

biologically not efficient

Crude and True protein True protein : Nitrogen compound

only as protein. Crude protein : All nitrogen

compounds including also Non Protein Nitrogen (NPN) in addition to protein.

NPN : free amino acids, amina, amonia, urea, biuret, nitrites, nitrates.

Protein Deficiency

Reduced appetite and feed intake Reduced birth weights and

growth Reduced colostrums and milk

production Decreased hormonal production Decreased fertility

Excessive Protein Intake by Animal

Excessive protein intake is deaminated in the animal body to amino group and carbon skeletons (fatty acids)

Deaminated amino acids are excreted in urine as waste (urea or uric acid)

Remaining carbon skeletons are used as energy source or stored as fat

Expensive process of supplying energy to the animal.

Protein or Nitrogenous Compounds in Feeds

True proteins Polymers of amino acids (18 to 20 different

amino acids) linked by peptide bonds Essential amino acids (nondispensable)

Have to be present in the diet (absorbed)

Arg Lys Trp Leu Ile Val Met Thr Phy His Nonessential amino acids (dispensable)

Synthesized in body tissues Glu Gly Asp Pro Ala Ser Cys Tyr

Proteins Peptides Amino acids

Non protein nitrogen Nitrogen not associated with protein

Free amino acids, nucleic acids, amines, ammonia, nitrates, nitrites, urea

Crude protein Total nitrogen x 6.25 Proteins on average contain 16%

nitrogen

Protein in Non- Ruminant Animals

Non-ruminant animals can not synthesize the essential amino acids fast enough to meet the animals needs therefore those essential amino acids must be provided in the ration

Need to feed balanced ration with the right balance of essential amino acids

If grains are combined in the correct combination they will provide a balanced ration.

Soybean meal is most commonly used

Ruminant animals generally synthesize the essential amino acids by the rumen at a rate to meet the needs of the animal

Can be met by feeding proteins of vegetable sources

Also by feeding urea (synthetic nitrogen source made from air, water and carbon)

Urea is mixed with the ration to to provide nitrogen for making amino acids in the ruminants body

Protein in Ruminant Animals

Feed Protein AcronymsNRC Publications

Crude protein Total N x 6.25DIP (RDP) Degraded intake proteinUIP (RUP) Undegraded intake proteinSolP, % CP Soluble proteinNPN, % CP Nonprotein nitrogenNDFIP, % CP Neutral detergent fiber insoluble

proteinADFIP, % CP Acid detergent fiber insoluble

proteinB1, B2, B3, % hr Rate constants for degradable

fractions

Average RuminalDegradation of Several Proteins

Soybean meal (Solvent processed) 75%Soybean meal ( Expeller processed) 50%Alfalfa 80%Corn proteins 62%Corn gluten meal 42%Corn gluten feed 80%Dried distillers grains 55%Blood meal 20%Feather meal 30%Urea 100%

Sources of Protein

Plant protein, incl. its by-products

Animal protein, incl. marine products

Single cell protein Non protein nitrogen (NPN)

Plant Protein

Plant protein are thought to be poor-quality protein because they lack some amino acids

Some plant protein contain anti nutritional factors and toxic, limiting their use in ration

Influencing factors : geographycal, types/species, stage of growth, part of plant

Plant Protein

Influencing factors : geographycal, types/species, stage of growth, part of plant

Plant by-products protein, affected also by : Processing, Composition of parts of the plant

Animal Protein

Animal source protein are considered good-quality proteins since they contain a good balance of essential amino acids

High digestibility Efficiently utilized by animal

Animal Protein

Influencing factors : geographycal, types/species, stage of growth, part of plant

Animal by-products protein, affected also by

Processing, Composition of parts of the plant

Protein determination

Analysis: Determine total N by Kjeldahl All N NH4

+

Determine as NH3

Total N x 6.25 = crude protein Peptide bond:

NH2

R1-C-C-NH O C-C=O

R2 N-C-COOHH R3

required