This study evaluated the effects of a modified soy oil (MSO) in diets with or without medium chain triglycerides from palm kernel oil (MCT).

The study utilized 1,840 pigs (~19 d of age; 5.4 ± 0.2 kg), 10 pens/treatment, and ~22 pigs/pen. Two barns were blocked separately by pen location and randomly allocated to treatments. Treatments were arranged as a 2 × 4 factorial utilizing diets containing one of four levels of MSO (0, 0.15, 0.25, or 0.40%) and two levels of MCT (without vs with [0.50% d 0 to 7; 0.25% d 7 to 41]). Pen weights were obtained on d 0, 7, 23, and 41 post-weaning, mortalities and removals were tracked, and growth performance parameters were calculated.

Constructed contrasts were: linear and quadratic main effects of MSO, main effect of MCT, and all possible interactions. Overall (d 0 to 41), there was a quadratic interaction (P < 0.01) between MSO and MCT for G:F (without MCT: 0.78, 0.78, 0.79, 0.76; with MCT: 0.78, 0.77, 0.78, 0.78 kg/kg). For growth performance parameters, no other interactions were significant (P > 0.10). Addition of MSO linearly increased (P < 0.01) d 41 BW (19.8, 20.3, 20.5, 20.8 kg), ADG (0.34, 0.35, 0.36, 0.37 kg/d), and ADFI (0.43, 0.46, 0.45, 0.48 kg/d). Including MCT in diets reduced (P < 0.05) d 41 BW (20.6, 20.1 kg), ADG (0.36, 0.35 kg/d), and ADFI (0.46, 0.45 kg/d). Probability of resulting in mortality and removals was linearly reduced (P < 0.01; 13.0, 8.2, 9.5, 6.6%) as MSO increased in the diet. A tendency for a linear interaction (P < 0.10) for probability of receiving injectable antibiotics was observed.