Administration of krill oil extends lifespan of fish Nothobranchius guentheri via enhancement of antioxidant system and suppression of NF-κB pathway

Krill oil (KO) extracted from Antarctic krill ( Euphausia superba ) mainly comprises phospholipids and triglycerides. KO has been shown to prolong the median lifespan of the nematode Caenorhabditis elegans , but to shorten the lifespan of long-lived F1 mice; therefore, it remains controversial over the life-extending property of KO. In this study, we clearly demonstrated that dietary intake of KO extended both the mean and maximum lifespans of aged male Nothobranchius guentheri ( p < 0.05), reduced the accumulation of lipofuscin (LF) ( p < 0.05) in the gills and senescence-associated β-galactosidase (SA-β-Gal) ( p < 0.05) in the caudal fins, and lowered the levels of protein oxidation ( p < 0.05), lipid peroxidation ( p < 0.01), and reactive oxygen species (ROS) ( p < 0.01) in the muscles and livers, indicating that KO possesses rejuvenation and anti-aging activity. We also showed that KO enhanced the activities of antioxidant enzymes catalase (CAT) ( p < 0.05), superoxide dismutase (SOD) ( p < 0.05), and glutathione peroxidase (GPX) ( p < 0.05) in aged male N. guentheri . In addition, KO administration effectively reversed histological lesions including inflammatory cell infiltration and structural collapse in the muscles and livers of aged N. guentheri and suppressed the nuclear factor kappa-B (NF-κB) signaling pathway ( p < 0.05), a master regulator of inflammation. Altogether, our study indicates that KO has anti-aging and rejuvenation property. It also suggests that KO exerts its anti-aging and rejuvenation effects via enhancement of the antioxidant system and suppression of the NF-κB signaling pathway.