Nutritional value of ingredients
The precision on assigning nutritional values to feed ingredients is becoming increasingly important due to the use of alternative ingredients and the implementation of more accurate systems to express requirements of energy, amino acids, and phosphorus in diet formulation. There are different methodologies for assigning nutritional values to feed ingredients. However, consistently using the same methodology across the feed ingredients used in diet formulation is key.
A common approach is to use nutritional composition databases from the National Research Council (NRC), the French National Institute for Agricultural Research (INRA), or the Brazilian Tables for Poultry and Swine. Additionally, nutritional values may be provided by the ingredient supplier. However, there are practical approaches that can be used to assign nutritional values to feed ingredients when values are not available or not similar to the reference ingredient in the databases. For approaches that require chemical analysis of feed ingredients, following a standardized sampling procedure is key.