Defintion and Roles Why are they needed Protein Structure Sources of protein Biological Value of protein Protein Metabolism in ruminants and monogastric

Protein

Protein is an essential organic compound for living cell and its highest concentration is found in animal muscle. Protein is needed for growth, tissue replacement, egg formation, energy and heat combustion Protein consists of one or more amino acids and absorbed into the body in the form of amino acid

Why do animals need protein? Protein /amino acids deficiency causes:

1. Slow growth rate 2. Egg production low 3. Egg size reduced 4. Feather growth disturbed 5. High fat deposition in tissue

Severe Protein deficiency causes:

1. Loss of growth approximately 6-7% 2. Hair losses 3. Egg production stop

Excess of protein/amino acids supply causes:

1. More moist feces due to increase of water consumption needed to excrete uric acid 2. Animals stress shown by the increase in adrenal glands production 3. Growth reduction 4. Reduction in fat deposition

How Protein in the feedstuff is measured? 1. Crude Protein = N * 6.25 by Kjeldahl method Compunds containing N include: 1. Protein, amino acids 2. Non-Protein Nitrogen (amines, nitrate, nitrogenous glycisides, glycolipid, vit B, nucleic acid)

How protein in feedstuff is measured (cont...)

2. Pure Protein Commonly used for poultry Determined by separating NPN using Cupric hydroxide or by heating

3. Amino Acids Amino acids are measured using HPLC method

Amino acids composition in some Feedstuff

Feedstuff Lysin (%) Methionin (%)Fishmeal 4.51 1.63Soybean meal 2.69 0,62Maize 0.26 0.18Rice bran 0.59 0.26

Use of Protein/Amino Acids in the body Monogastric or Poultry - Protein digestibility occurs in stomach and small intestine to produce amino acids for absorption

- Not all feed protein consumed is utilised for production and this in reflected in digestibility value of each feedstuff

- Quality of protein or amino acids will influence quality of the products

Protein Digestibility of some poultry ingredients (True digestible protein %)

Feestuff True Digestible Protein (%)

Wheat 86.9Sorghum 60.4Corn gluten 92.9Corn gluten meal 93.0Soybean meal 48% 89.2Soybean meal 50% 92.4Meat meal (low quality) 66.1Meat meal (high quality) 78.4Fish meal (60%) 88.8Fish meal (72%) 88.8

Use of Protein/Amino Acids in the body Ruminants - Protein digestibility occurs in rumen, abmasum and duodenum

- Protein entering rumen will be digested into ammonia for microbial growth protein synthesis

- Protein directly goes to abomasum without being degraded in the rumen is called Bypass Protein.

Digestible protein in ruminants

protein peptide aaprotease

nh3 co2

fa

Microbial protein

ATP

BLOOD VESSEL

UREA (EXCRETED IN URINE)

peptdase

Protein Degradation in the Rumen

Approximately 40% of rumen bacterials have proteolityc activity

Protease attached in the surface of feed particle and ready to have contact with any substrates

Enzymes have an optimal action at pH 6-7

Deamination of AA forms branch chain of VFA such as: iso-butyric acid, valeric acid, iso-leucin. The branch chains are used as precursor for microbial growth

Protozoa cannot use NH3, but they use N coming from digestible microbes by intracelluler protease enzime

NH3 may be originated from NPN (grass or silage)

P or S sources need to be supplied from the feed for microbial protein synthesis. Phosphate for nucleic acid, whilst S for metionin and sistein synthesis in the microbial protein

NH3 in rumen content

Breakdown of Protein in the feed Biosynthesis of microbial

protein

Absorption into the blood

Transfer to PosteriorRecycling of urea

Digestibility of poultry feeds

a.Apparent AA digestibility (%) AA consumption - AA excreted ------------------------------------------------- x 100% AA consumption

b. True AA digestibility (%)

AA consumption – (AA excreted-Endog AA) ------------------------------------------------------------------- x 100% AA consumption