Nutrient Analysis

Question 1

Endogenous Amino Acids:

Answer 1

Amino acids secreted into gastrointestinal tract. Endogenous amino acids are digestive secretions, which may originate from salivary, bile, pancreas, and the gastrointestinal tract.

Question 2

Relative Bioavailabilty:

Answer 2

Relative amount of a nutrient that is retained or elicits a specific response compared with a standard source that is regarded as highly available. The standard source is given a value of 100.

Question 3

Eplain the basis of the correction factor for nitrogen when calculating crude protein content of animal feeds.

Answer 3

• Crude Protein is crude.
• Measuring the nitrogen content and multiplying by 6.25
• Factor is based on average N content for protein (16%), but is not accurate for all ingredients
• 100/16 = 6.25

Question 4

Why is a nitrogen correction factor used in calculating apparent metabolizable energy?

Answer 4

• Broilers allowed to eat ad libitum for 48 hours.
• Metabolizable energy of the basal diet is determined

and experimental diets consist of the test ingredient added to the basal diet.

• Feed and excreta are weighed during the 48 hour period.
• Feed and excreta are analyzed for nitrogen and

energy.

• Birds excrete excess nitrogen as uric acid.
• Uric acid is a purine and is secreted in excreta by the kidneys.
• Energy required for uric acid formation is 8.22 kcal/kg.