Early postnatal exposure to a cafeteria diet interferes with recency and spatial memory, but not open field habituation in adolescent rats.

The cafeteria diet (CD), an experimental diet that mimics the obesogenic Western diet, can impair memory in adult rats. However, the suckling period is also particularly susceptible to diet-induced behavioural modification. Here, following exposure to CD feeding during lactation, 24- to 26-day-old offspring were tested to determine maternal dietary effects on either open field habituation, object location (OL) learning or on recency learning. Whereas no impact on habituation learning could be demonstrated, both OL and recency memory were impaired. In controls (C), OL memory was shown both after a 5 min (p < .05) or 60 min (p < .001) inter-trial interval (ITI). After the 60 min ITI, the difference between C and CD was significant (p < .05). Learning did not occur in the CD group at any time point and was not observed after the 24hr ITI in in either group. Whereas control rats demonstrated intact recency memory (p < .00001), no learning occurred in the CD group. Both groups differed significantly in their exploration ratios (p < .01). This study suggests a detrimental effect of exposure to an unhealthy Western diet during lactation, on cognitive functions in adolescent rats. These results could have implications for human cognition in the context of obesity epidemic.