Peanut meal extract fermented with Bacillus natto attenuates physiological and behavioural deficits in a d-galactose-induced ageing rat model

Our previous studies have shown that the nutritional properties of peanut meal after fermentation are markedly improved. In this study, in order to facilitate the further utilisation of peanut meal, we investigated the effects of its fermentation extract by Bacillus natto (FE) on cognitive ability, antioxidant activity of brain and protein expression of hippocampus of ageing rats induced by d-galactose. Seventy-two female sd rats aged 4–5 months were randomly divided into six groups: normal control group, ageing model group, FE low-dose group, FE medium-dose group, FE high-dose group and vitamin E positive control group. Morris water maze (MWM) test was performed to evaluate their effects on learning and memory ability in ageing rats. Superoxide dismutase (SOD) activity and malondialdehyde (MDA) content of brain, HE staining and the expression of γ-aminobutyric acid receptor 1 (GABABR1) and N-methyl-d-aspartic acid 2B receptor in the hippocampus of rats were measured. The results show that FE supplementation can effectively alleviate the decrease of thymus index induced by ageing, decrease the escape latency of MWM by 66·06 %, brain MDA by 28·04 %, hippocampus GABABR1 expression by 7·98 % and increase brain SOD by 63·54 % in ageing model rats. This study provides evidence for its anti-ageing effects and is a research basis for potential nutritional benefits of underutilised food by-products.