Marine collagen peptide isolated from Chum Salmon (Oncorhynchus keta) skin facilitates learning and memory in aged C57BL/6J mice

To observe the neuroprotective effects of marine collagen peptide (MCP) isolated from Chum Salmon (Oncorhynchus keta) skin by enzymatic hydrolysis, 20-month-old female C57BL/6J mice were fed with chow diet, 0.22%, 0.44% or 1.32% (wt/wt) MCP diet for 3 months. Comparing with aged control group, the abilities of passive avoidance and spatial memory and learning were significantly enhanced evaluated by step-down test and Morris water maze respectively. Furthermore, the abilities of learning and memory had no significant difference between 0.44% and 1.32% MCP treated groups and young control group. The alleviated oxidative stress, reduced apoptotic neurons, up-regulated expression of brain-derived neurotrophic factor (BDNF) and postsynaptic density protein 95 (PSD95) were observed in MCP treated groups compared with aged control group. Our research revealed that there were no significant difference between 0.44% and 1.32% MCP treated groups and young control group. These findings suggest that MCP could be a candidate for functional food to relieve memory deficits associated with aging.