The objective of this experiment was to investigate the influence of weaning stress and an antioxidant blend on gut health and free radical metabolism in postweaning pigs. A total of 96 pigs from 12 litters were randomly divided by litter to 3 groups with 4 litters each. The control group and the weaning group were fed the basal diet, and the antioxidant group was fed the basal diet supplemented with an antioxidant blend. The control group was suckling normally during the experimental period and the other 2 treatments were weaned at 21 d of age. Morphology in different parts of the intestines was used as a measure of intestinal barrier function. Activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and the concentrations of malondialdehyde (MDA), NO, H(2)O(2), and O(2) were measured in serum. Activities of the digestive enzymes, including sucrase, maltase, amylase, lipase, and pepsin, were measured at 24 d of age for all treatments. Gene expressions of free radicals, digestive enzymes, or antioxidant enzymes were selected for quantitative reverse transcription-PCR analyses. Results showed that weaning resulted in reductions (P< 0.05) in the villus height and width, and activity of digestive enzymes. Activity of SOD decreased (P < 0.05) and the concentrations of MDA, NO, and H(2)O(2) increased (P < 0.05) after weaning. The expression results indicated that the genes related to the antioxidant enzymes and digestive enzymes were down regulated (P < 0.05) after weaning. Tumor protein 53, which regulates reactive oxygen-species generation, tended to increase (P < 0.10) in the weaning group. The concentration of PPARγ coactivator-1α (PGC-1α), which plays an important protective role against oxidative stress by regulating the expression of mitochondrial antioxidants, was reduced (P < 0.05) in weaning pigs and increased (P < 0.01) in antioxidant pigs compared with the control pigs. Results indicated that intestinal dysfunction occurred after weaning and there was an inhibition of the antioxidant system. The antioxidant blend has the potential to prevent free radical-induced damage and suppress oxidative stress by modulating the expressions of tumor protein 53 and PGC-1α genes.

Secreted extracellular vesicles play an important role in pathogen-host interactions. Increased knowledge of schistosome extracellular vesicles could provide insights into schistosome-host interactions and enable the development of novel intervention strategies to inhibit parasitic processes and lessen disease transmission. Here, we describe biochemical characterization of Schistosoma japonicum exosome-like vesicles (S. japonicum EVs). A total of 403 proteins were identified in S. japonicum EVs, and bioinformatics analyses indicated that these proteins were mainly involved in binding, catalytic activity, and translation regulatory activity. Next, we characterized the population of small RNAs associated with S. japonicum EVs. Further studies demonstrated that mammalian cells could internalize S. japonicum EVs and transfer their cargo miRNAs to recipient cells. Additionally, we found that a specific miRNA, likely originating from a final host, ocu-miR-191–5p, is also associated with S. japonicum EVs. Overall, our findings demonstrate that S. japonicum EVs could be implicated in the pathogenesis of schistosomiasis via a mechanism involving the transfer of their cargo miRNAs to hosts. Our findings provide novel insights into the mechanisms of schistosome-host interactions.

No abstract