Effects of a Feed Additive Premix Inclusion in diets of Varying Composition on metabolizable Energy, Standardized Ileal Digestibility of Amino Acids, and Growth Performance in Growing- finishing Pigs

Three experiments were conducted to determine the effect of FAP addition on ATTD DM and GE, DE, ME, SID CP and AA, and growth performance of grow-finish pigs. Treatments were arranged in a 3 × 2 factorial with 3 diet types (corn-, sorghum-, or sorghum and DDGS- based diets) and two FAP inclusions (0 or 0.13%). In Exp. 1, 12 barrows were randomly allotted to a replicated 6 × 6 Latin square design with 6 diets and 6 periods to determine energy metabolism. For Exp. 2, 14 barrows were surgically fitted with a T-cannula at the distal ileum and were randomly allotted to a replicated 7 × 7 Latin square design with 7 diets, including N-free, and 7 periods for the determination of SID of CP and AA. For Exp. 3, a total of 360 mixed sex pigs (DNA 600 x 241; Initial BW: 52.8 kg) were housed in 36 pens with 10 pigs per pen. In Exp. 1, there was a diet type x FAP interaction (P < 0.04) for ATTD of DM and GE, DE, and ME. Addition of the FAP to the corn-, sorghum, or sorghum and DDGS-based diet decreased (P < 0.05) ATTD of DM and GE as compared to diets without FAP. The addition of the FAP to the corn-based diet reduced (P < 0.05) concentrations of DE and ME as compared to diets without FAP, but there was no evidence of differences in the remaining diets. For Exp. 2, there was a diet type × FAP interaction (P < 0.02) for SID of Arg, Trp, Asp, Glu, Gly, and Tyr where addition of FAP to corn-based diets decreased (P < 0.05) SID of Arg, Trp, Glu, Gly, and Tyr. Addition of FAP to sorghum-based diets decreased (P < 0.05) SID of Trp and increased (P < 0.05) digestibility of Asp. Addition of FAP to sorghum and DDGS-based diets increased (P < 0.05) SID of Trp and Asp. Addition of FAP to all diets decreased (P < 0.03) SID of Leu and Lys. For Exp. 3, there was a tendency for an interaction (P = 0.122) for overall ADG. Pigs fed sorghum diets without FAP had improved (P < 0.05) ADG compared to those fed sorghum diets with FAP, but there was no evidence of difference in the remaining diets. For main effects of FAP, there was no evidence of difference in ADG or ADFI; however, pigs fed diets with FAP had a tendency for poorer (P = 0.06) G:F compared to those without FAP. The addition of the FAP (containing enzymes, prebiotics, plant extracts, and acidifier components) did not improve digestibility of diets or performance of pigs fed varying diet compositions.