Enterococcus Durans J396 Isolated from the Intestine of a Pig Enhances the Antioxidant Activity in Caenorhabditis Elegans.

Enterococcus durans is a potential probiotic with beneficial for the health of people and animals. However, the understanding of the antioxidant activity of E. durans is limited. In this study, the antioxidant activity of E. durans isolate J396 was investigated. The strain was well tolerant to heat stress and showed extensively resistant to acid and bile salts. In vitro, the DPPH radical scavenging ability of J396 was 89.95%. Feeding of Caenorhabditis elegans with J396 did not affect nematodes growth and reproduction, and significantly prolonged the lifespan of the nematodes. In addition, the superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-px), and total antioxidant capacity (T-AOC) activities increased by 57.05%, 36.25%, 82.88%, and 49.96%, respectively. The malondialdehyde (MDA), lipofuscin, and reactive oxygen species (ROS) levels were reduced by 28.40%, 28.72%, and 65.57%, respectively. E. durans J396 effectively protected C. elegans from hydrogen peroxide-induced oxidative stress damage. The activity of SOD, CAT, GSH-px, and T-AOC increased by 142.03%, 74.86%, 62.01%, and 94.16%, respectively. Feeding E. durans J396 to C. elegans decreased MDA, lipofuscin, and ROS by 33.59%, 19.70%, and 56.42%, respectively. RT-qPCR analysis showed that the feeding of C. elegans with J396 upregulated the expressions levels of nsy-1, pmk-1, skn-1, and sod-3 in C. elegans. Our study confirmed the antioxidant properties of E. durans J396, indicating its potential application in the pharmaceutical industry and the antioxidant therapy for animals.