Effect of Selenium-Enriched Probiotics on Selenoprotein Gene Expression of Piglets Raised in a High-Temperature Environment

Abstract Text:

Heat stress is considered as a detrimental factor that negatively affects animal health and production performance. We have reported that dietary supplementation of selenium-enriched probiotics (SeP) has additive effects of probiotics and selenium in improving antioxidant status and immune function of piglets raised in a high-temperature environment (25~40°C). It is known that the biological effects of selenium are exerted through selenoproteins. The objective of this study was to further investigate the SeP effect on the gene expression of three selenoproteins, glutathione peroxidase 1 (GPx1), GPx4 and thioredoxin reductase 1 (TR1), which play important roles in animal antioxidant status and immune responses. Forty-eight crossbred weanling piglets (BW 7.9 ± 0.5 kg) were randomly assigned to 4 dietary treatments (12 piglets/treatment) and fed ad libitum for 42 days a basal diet (Con, 0.16 mg Se/kg-diet), or a basal diet supplemented with probiotics (P, 0.16 mg Se/kg-diet), sodium selenite (SS, 0.46 mg Se/kg-diet) or SeP (0.46 mg Se/kg-diet). At the end of the trial, three piglets were randomly selected from each group (n=3) for liver, kidney and spleen tissue collection and total RNA extraction. Real-time quantitative RT-PCR analysis of the RNA samples showed that: (1) For GPx1 and TR1 mRNA levels, although no increases were found in either liver, kidney, or spleen for the P group relative to the Con group, significant increases (P < 0.05) were detected in the SS group. The SeP group showed further increases (P < 0.05) when compared to the SS group in either one of the three tissues. (2) For GPx4 mRNA level, no significant differences were found among the four treatment groups in either liver, kidney or spleen tissue.  These results suggest that the beneficial effects of SeP in improving piglets’ antioxidant status and immune function may be exerted through GPx1 and TR1 proteins, but not GPx4 protein. These results also suggest that the organic form of Se (in SeP) is better than inorganic form of Se (in SS) in terms of improving piglets’ antioxidant status and immune function. This project was supported in part by the National Natural Science Foundation of China and Mississippi Agricultural and Forestry Experiment Station.

Keywords:

selenium-enriched probiotics, selenoprotein, gene expression, pig