Objective  To investigate the effects of intrauterine growth retardation (IUGR) on immune organs and plasma cytokine contents in growing-finishing pigs.

Method  A total of 36 pregnant sows with similar body conditions were selected. After delivery, one IUGR piglet (IUGR group) and one normal born weight piglet (control group) were selected from each litter, respectively. After weaning, the animals were fed with the same basic diet. When the average body weight (BW) of control pigs gained 25, 50 and 100 kg, seven pigs per group were randomly selected to collect blood samples by precaval vein, and plasma cytokine contents were measured. Twelve pigs in each group were killed for isolating and weighing liver, spleen, and kidney to calculate their organ indices.

Result  Compared to the control group with the same BW, the liver, spleen and kidney weights of IUGR pigs decreased by 32.63%, 35.07% and 34.28% at 25 kg BW stage (P<0.01) and decreased by 22.68%, 40.05% and 33.03% at 50 kg BW stage, respectively. The content of plasma interleukin IL-1β in IUGR pigs at 25 and 50 kg BW stages decreased by 20.66% and 27.21% (P<0.05), respectively. Compared to the control group at 50 kg BW stage, the liver index of IUGR pigs increased by 16.25% (P<0.05) and the ratio of IL-1β to IL-10 decreased by 40.67% (P<0.01). Compared to the control group at 100 kg BW stage, the liver index and spleen index of IUGR pigs increased by 10.94% (P<0.05) and 21.74% (P<0.01), respectively, while the liver weight and kidney weight decreased by 13.97% and 17.51% (P<0.01), respectively.

Conclusion  IUGR can alter the organ indices and weights of liver, spleen and kidney, decrease plasma IL-1β content, and therefore influences the immune function in growing-finishing pigs.