A total of forty 21-d-old weaned and crossbred pigs [(Landrace × Yorkshire) × Duroc] with an average initial body weight of 4.43 ± 1.41 kg were used for this 2 wk experiment. There were four treatments. Each treatment had 10 replicates with five pigs per pen. Treatments were as follows: (1) microencapsulated complex of organic acids and essential oils (MOE)-, lipopolysaccharide (LPS)+; (2) MOE-, LPS-; (3) 0.2% MOE+, LPS+; and (4) 0.2% MOE+, LPS-. Final body weight, body weight gain, average daily gain, and average daily feed intake were significantly different between MOE+ and MOE- (P < 0.05). Based on the results of MOE+, crude protein digestibility was significantly higher than for MOE- (P < 0.05). However, LPS+ was significantly higher than LPS- in the 4, 8, 12, and 16 h (P < 0.05). From a comparison of blood profiles, cortisol, tumor necrosis factor-α, interleukin-1β, neutrophil, lymphocyte, red blood cell, hemoglobin, and hematocrit were significantly different between LPS+ and LPS- (P < 0.05). The immunoglobulin G, white blood cell, and eosinophil were significantly different between LPS and MOE treatments (P < 0.05). In summary, MOE had a potentially good effect on growth performance and some part of immune response in weaned pigs.