It is about protein digestion and metabolism in poultry

1. Protein Digestion and Metabolism in
Poultry
Saurabh Rajvaidya
PhD Scholar, NDRI, Karnal

2. Digestive System of Poultry
• First site of protein
digestion

3. Initiation of gastric juice secreation in proventriculus
Ingestion of feed
Vagus nerve stimulation
Digestion
In low pH medium Pepsinogen get converts to pepsin
Pepsin
Proventriculus secreats HCl and Pepsinogen (Inactive)
Pepsin-2 active centres-fast degradation of protein
Effect on several different peptide linkages
Most pronounced effect is between
Leucine and valine, Tyrosine and Leucine, Phenyle alanine
and phenyle alanine and Phenyle alanine and tyrosine

5. • 5 types of pepsinogens have been extracted
from chicken proventriculus

6. Feed (Protein-
Complex form)
HCl
Heat treatment
(Expanding,
Extrusion, Cooking,
Pelleting)
Denaturation

7. • Feed mixed with the fluid reaches to gizzard
• Gizzard is important organ for grinding of feed
• Insoluble grit plays important role
I. Provide additional surface for grinding
II. Stimulate motility of gizzard
• Coarse feed particles(whole grains with min
Processing)-grit is important
• Feed-ground-No gizzard-No effect on digestion
Role of Gizzard in Digestion

8. Digestion in Small Intestine
Pancreas
Group of
Enzymes
Zymogen
(Inactive)
Trypsinogen
Trypsin
Intestinal mucosa Enterokinase

9. Duodenum
Elastase
Chymotrypsin
Trypsin
Lysine
and/Arginine Non specificAromatic A A

10. • Exopeptidase are secreated from pancreas
• Carboxypeptide A and B
• Act on terminal carboxy bond
• Remove Amino acids
• Collagenases converts collagen to small peptides
• Jejunal wall-erepsin and polynucleosidase
• Erepsin converts Small peptides to AA and
dipeptides
• Polynucleosidase converts Nucleotides to
mononucleotides

11. • Endopeptidases act on peptides and converts
them in small peptides (2-10 AA) or
sometimes in free Amino acids
• In lumen-peptidases-desquamated mucosal
cells and intestinal mucosa

13. Reaches to intestinal mucosal cells
Peptides
Sodium pump absorption
Absorption
Cell cytoplasm having enzymes
Complete hydrolysis of peptides in free amino acids

16. Nitrogen Pool
carbon dioxide, water,
uric acid, ATP

17. Transamination

18. • Portal system do not complete reflect Amino
acid pattern of diet because some AA are
incorporated in protein of mucosa

19. • In some proteins peptide absorption is more rather than
free amino acids
• Trace amount of peptides in plasma may be present
• In jejunum peptide uptake is more
• In ileum amino acid uptake is more
• L-form are rapidly absorbed than D-form
• Only D-methionine has more affinity than L

20. • The catabolism process (in liver) involves removal of
amino group and the resulting keto acids then it oxidized
to form energy (ATP), glucose and lipid
• Caeca is the major site for microbial protein degradation
which further degrades in amino acids and get absorbed

21. Transamination

22. • Sources of endogenous proteins
• Saliva
• Gastric juice
• Pancreatic juice
• Desquamated epithelial cells

23. • In Kidney tubules reabsorption of Amino acids occurs
• High level of lysine fed- More Urinary losses of Arginine
• In poultry the waste products are metabolised principally in
uric acid for excreation
Excreation

27. Thank you