Abstract: 【Objective】 This study was aimed to conduct the effects of oregano essential oil and colostrum complex (EC) with different levels on growth performance,serum biochemical indicators,antioxidant and immune capacity in opportunity piglets (body weight were <1.20 kg),further provide technical basis for promoting healthy growth of opportunity piglets.【Method】 A total of 128 binary sows (Landrace×Large White) with similar body condition,parity (2/3) and litter sizes were divided into 4 groups randomly,32 sows per group,all sows were fed as the same diet formula.Opportunity piglets from each sow group were administrated 0(control,CON),2(EC2,oral administration once),4(EC4,for 2 consecutive days) and 6 mL(EC6,for 3 consecutive days) EC by gavage after birth,respectively.The trial period lasted for 21 days from birth to weaning.The birth weight and weaning weight of all piglets were recorded to calculate average daily gain (ADG).Serum of opportunity piglets was collected at the end of experiment to measure the antioxidant and immune indexes.【Result】 Compared to CON,feeding EC after birth significantly increased weaning weight and ADG (P<0.05),and significantly decreased diarrhea indexes of opportunity pigs (P<0.05).The mortality in EC4 and EC6 decreased significantly (P<0.05).And the diarrhea indexes and mortality in EC4 were significantly lower than EC2 (P<0.05).The activities of ALT and AST in EC6 were significantly lower than CON (P<0.05),while the concentrations of GLB,IgA,IgG and IgM,and the activities of SOD and GSH-Px were significantly higher than CON and EC2 (P<0.05).【Conclusion】 In summary,neonatal opportunity piglets administered EC could improve growth performance,and continuous feeding for 2 days could significantly decrease diarrhea and death;While continuous feeding for 3 days could improve immune and antioxidant property.

Key words: opportunity piglets; essential oil and colostrum complex; growth performance; antioxidant property; immune performance