Fifty-four multiparous large white sows were used to determine the effects of supplementing oregano essential oil (OEO) to the gestation and lactation diets on oxidative stress status, lactation feed intake, and their piglet performance. Two groups were fed diets with (OEO; n = 28) or without (Control; n = 26) supplemental 15 mg/kg OEO during gestation and lactation. The serum levels of reactive oxygen species (ROS) (P < 0.05), 8-hydroxy-deoxyguanosine (8-OHdG) (P < 0.05), and thiobarbituric acid reactive substances (TBARS) (P < 0.05) were higher during gestation (days 90 and 109) and lactation (days 1 and 3) than in early gestation (day 10). Compared with the control group, the OEO diet significantly reduced sows' serum concentrations of 8-OHdG (P < 0.05) and TBARS (P < 0.01) on day 1 of lactation. The OEO diet increased the sows' counts of faecal lactobacillus (P < 0.001) while reducing Escherichia coli (P < 0.001) and Enterococcus (P < 0.001). In the third week of lactation the treatment tended to increase sow's feed intake (P = 0.07), which resulted in higher average daily gain (P < 0.01) of piglets. Our results demonstrated that there is an increased systemic oxidative stress during late gestation and early lactation of sows. The OEO supplementation to sows' diet improved performance of their piglets, which may be attributed to the reduced oxidative stress.

Although dietary fibers contribute to health and physiology primarily via the fermentative actions of the gut microbiota of the hosts, few studies have focused on how these interactions influence the metabolic status of sows. Here, the effects of inclusion of konjac flour (KF) in a gestation diet on oxidative stress status, insulin sensitivity, and gut microbiota were investigated to elucidate the correlation between the microbiota and metabolic changes in sows. Sows were assigned to either control or 2.2% KF dietary treatment during gestation. The gut microbiota population in sows during gestation and lactation was assessed by 16S rRNA gene sequencing. The oxidative stress parameters, homeostasis model assessment (HOMA) values, and fatty acids in the blood of sows were also assessed. Compared to the control diet group, KF significantly reduced the serum levels of reactive oxygen species (ROS) and 8-hydroxy-deoxyguanosine (8-OHdG) but increased the serum concentrations of glutathione peroxidase (GSH-Px) in sows on day 1 in lactation. Additionally, sows in the KF group had a lower HOMA insulin resistance value but a higher HOMA insulin sensitivity (HOMA-IS) value. KF induced changes in the gut microbial composition at the phylum and genus levels. The increased relative abundances of Akkermansia and Roseburia in the KF group were positively correlated with the HOMA-IS. Overall, dietary KF alleviated oxidative stress and improved insulin sensitivity of sows, and the changes in the gut microbiota in response to KF may have been correlated with the host metabolism response. IMPORTANCETo date, the effect of dietary fiber on metabolism responses and gut microbiota in sows has not been investigated. Here, KF supplementation of a gestation diet in sows was found to alleviate oxidative stress and to improve insulin sensitivity. Pyrosequencing analysis revealed that KF treatment induces changes in the gut microbiota composition at the phylum and genus levels. Moreover, the changes of gut microbiota in response to KF may be correlated with the host metabolism response.