Summative Equations for Calculating Digestibility. Milk2000 equation indicates that Starch is not an Ideal Nutritive Entity and removes it from NFC. TDN1x = tdCP + tdFA + tdNSNFC + tdST + tdNDF - 7. Non-starch NFC (NSNFC) = (NFC – Starch) has a variable Starch Digestibility depending on corn silage %DM and processing.

After a diet is formulated using feed energy values, various adjustments based on total diet composition and feed intake may be needed to obtain a more accurate estimate of diet energy. Examples of associative effects include the effect of diet CP concentration on fiber and DM digestibility.

Digestion trials can be performed to measure the digestibility of a range of feed components including the general nutrient class or a specific component within the class. The two measures of digestibility are apparent and true digestibility.

Digestibility is a measure of the degree of net absorption of nutrients in the digestive tract of fish. Carbohydrate, protein, and lipid must be degraded to absorbable units (e.g., monosaccharides, amino acids, FAs).