Casein

Effects of increasing dietary protein on standardized ileal digestibility of amino acids in diets fed to growing pigs

Apparent ileal digestibility (AID) of amino acids (AA) is affected by dietary AA levels because of different contributions of endogenous AA to the ileal digesta from pigs fed diets with different levels of AA. Because of the influence of dietary protein and AA on calculated values for AID, values for AID obtained in individual feed ingredients are not always additive in mixed diets. Therefore, values for standardized ileal digestibility (SID) of AA, which are corrected for the basal ileal endogenous losses of AA, are used in diet formulations to avoid the influence of endogenous AA on digestibility values, and SID values are, therefore, additive in mixed diets.

When the direct procedure is used to determine AA digestibility, diets containing cereal grains are sometimes formulated to contain AA below the requirement. In contrast, if the SID of oilseed meals or other protein-rich ingredients are determined, concentrations of AA may be at or above the requirement. Because the influence of the basal endogenous losses of AA is eliminated in the calculations of SID values, it is assumed that values for SID are not influenced by dietary concentrations of AA. However, to our knowledge this hypothesis has not been experimentally verified, but it is an important question because it may influence how diets used in digestibility experiments are formulated. Therefore, four experiments were conducted to test the hypothesis that the SID of AA by growing pigs is not influenced by dietary AA levels.

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Ileal digestibility of amino acids in conventional, fermented, and enzyme-treated soybean meal and in soy protein isolate, fish meal, and casein fed to weanling pigs

Cervantes-Pahm, S. F., and H. H. Stein. 2010. Ileal digestibility of amino acids in conventional, fermented, and enzyme treated soybean meal and in soy protein isolate, fishmeal, and casein fed to weanling pigs. J. Anim. Sci.  88:2674-2683. Link to full text (.pdf)

Amino acid digestibility of protein sources fed to weanling pigs

Cervantes-Pahm, S. F., and H. H. Stein. 2007. Amino acid digestibility of protein sources fed to weanling pigs. J. Anim. Sci. 85(Suppl. 2):105 (Abstr.) Link to abstract (.pdf)

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Nucleotide deficiencies in starter diets for weanling pigs

Mateo, C. D. and H. H. Stein. 2004. Page 55 in Nutritional Biotechnology in the Feed Industry. Proc. Alltech's 20th Annual Symp., Lexington, KY, USA, May 23-26, 2004, Suppl. 1 (Abstr.) Link to abstract (.pdf)

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Apparent and true ileal protein and amino acid digestibilities of casein for growing pigs and sows

Stein, H. H., J. Escobar, and R. A. Easter. 1998. Apparent and true ileal protein and amino acid digestibilities of casein for growing pigs and sows. J. Anim. Sci. 76(Suppl. 1):62 (Abstr.)

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