Effect of Dietary Carbadox on Apparent Ileal Digestibility of Amino Acids in Weanling Pigs

Problem statement: The objective of this experiment was to determine the effects of carbadox on Apparent Ileal Digestibility (AID) of Amino Acid (AA) by nursery pigs. Approach: Fifteen weanling barrows (initial BW: 9.6 kg) were surgically fitted with a T-cannula in the distal ileum. Animals were randomly allocated to three dietary treatments with five pigs per treatment during a 6- period experiment. Dietary treatments included: (1) a basal diet (BD) containing mainly corn and soybean meal, (2) BD + 27.5 mg kg^-1 of carbadox and (3) BD + 55.0 mg kg^-1 of carbadox. Treatment diets were provided during period 2-4; the BD was fed to all pigs during period 1, 5 and 6. Ileal samples were collected on d 6 and 7 of each period. Results: In pigs fed only the BD throughout the experiment, the AID of CP and many AA was greater during period 2-4 than during period 1 (p<0.05). This showed that the AID of CP and AA increased during the first few wk of the experiment. This analysis showed that pigs fed the diet containing 55.0 mg kg^-1 of carbadox had greater increases (p<0.05) in the AID of CP and most AA from period 1 to period 2-4 than pigs that were fed the diet containing no carbadox. The AID for some AA was less during period 5 and 6 compared with period 2-4 for pigs fed diets supplemented with 27.5 or 55.0 mg kg^-1 of carbadox (p<0.05). This observation suggests that there is no carryover effect of carbadox on AA digestibility. Conclusion: Inclusion of carbadox at 55.0 mg kg^-1 in diets fed to weanling pigs increased the AID of AA, but carryover effects of dietary carbadox were not observed.