Dietary intake of β-glucans can prolong lifespan and exert an anti-oxidant action of aged fish Nothobranchius guentheri.

One of the widely accepted conjectures regarding mechanisms of aging is probably the oxidative stress hypothesis. β-1,3-Glucans, well-known immunostimulants, have been shown to increase non-specific immunity and resistance against infections or pathogenic bacteria in several fish species, but its anti-aging function remains poorly understood. By feeding of β-1,3-glucans to the annual fish Nothobranchius guentheri, we detected the survivorship of the fish and estimated the development of age-related biomarkers at different stages. We first showed that administration of β-1,3-glucans was able to prolong the life span of the fish (p<0.05). We then showed that β-1,3-glucans clearly reduced the accumulation of lipofuscin in the gills and the senescence-associated-β-galactosidase in the caudal fins. Moreover, β-1,3-glucans were able to lower the levels of protein oxidation, lipid peroxidation and reactive oxygen species in the muscles. Finally, β-1,3-glucans could promote the activities of the antioxidant enzymes, including catalase, superoxide dismutase and glutathione peroxidase in the fish, and slow down the increase of P66shc, a critical factor involved in the regulation of intracellular reactive oxygen species contents. These data together suggest for the first time that β-1,3-glucans can extend the lifespan, delay the onset of age-related biomarkers and exert an antioxidant action of the aged fish N. guentheri. It also implies that β-1,3-glucans may be potentially useful for health care in the elderly, including extension of the lifespan.