Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)

Department / School

Animal Science


Nine growing barrows were used to determine apparent ileal digestibility coefficients (AID) and apparent total tract digestibility coefficients (ATTD) of calcium (Ca), and phosphorus (P) in low phytate corn (LPC), normal corn (NC), and soybean meal (SBM). The AID and the standardized ileal digestibility coefficients (SID) of CP and AA were also determined for these feedstuffs. Nine diets were formulated and fed to the animals in a 9 x 9 Latin Square design. Diets 1 and 2 contained LPC and NC, respectively, as the sole source of CP, AA, Ca, and P. Diets 3 and 4 were identical to diets 1 and 2 with the exception that limestone (iCa) and monosodium phosphate (iP) were added to these diets. Diet 5 contained SBM as the sole source of CP, AA, Ca, and P. Diet 6 was based on SBM with iCa and iP added. Diet 7 contained LPC, SBM, iCa, and iP, likewise, diet 8 contained NC, SBM, iCa, and iP. Diet 9 was a protein-free diet, which allowed for the calculation of endogenous losses of CP and AA. Diets 3, 4, 6, 7, and 8 were formulated to contain similar Ca:digestible P ratios. The results of the experiment indicated that the AID and ATTD of Ca and P were higher (P < 0.05) in LPC compared to NC. No differences (P > 0.10) were found when comparing AID of Ca and P to ATTD of Ca and P within the same diet. The AID of arginine (Arg), aspartate (Asp), glycine (Gly), isoleucine (Ile), lysine (Lys), phenylalanine (Phe), threonine (Thr), and valine were higher (P < 0.05) in LPC than in NC. The AID of all AA in SBM were higher (P < 0.05) than in both corns with the exception of alanine (Ala), cysteine (Cys ), leucine (Leu), and methionine (Met). The SID of Lys, Phe, and threonine (Thr) were higher (P < 0.05) in LPC than in NC. The SID of Arg, histidine (His), and Lys were higher (P < 0.05) in SBM compared to both corns. This research indicates that LPC has a higher digestibility of Ca and P than C and, therefore, less inorganic Ca and P need to be supplemented when feeding diets based on LPC rather than NC. The AA digestibility in LPC is at least as high as in NC. When measuring Ca or P digestibility at either the distal ileum or using total tract digestibility no differences were found, therefore, either method is an accurate depiction of what is digested by the animal.

Library of Congress Subject Headings

Swine -- Feeding and feeds Corn as feed Calcium Phosphorus Amino acids



Number of Pages



South Dakota State University