(2014) The impact of cafeteria feeding during lactation in the rat on novel object discrimination in the offspring. The Nottingham ePrints service makes this work by researchers of the University of Nottingham available open access under the following conditions. A note on versions: The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.

There is increasing evidence that hyperenergetic diets have an impact on memory in rodents. However, it is largely unknown how diets, such as a cafeteria diet (CD), that mimic a Western-type diet act on learning and memory, in particular when fed during early stages of development. Here, we fed lactating dams a CD and exposed both male and female offspring to a novel object discrimination (NOD) task, a two-trial test of recognition memory in which rats exposed to two identical objects during a training/familiarisation trial can discriminate a novel from a familiar object during the subsequent choice trial. The choice trial was performed following inter-trial interval (ITI) delays of up to 4 h. Maternal diet did not have an impact on exploration of the objects by either sex during the familiarisation trial. Control males discriminated the novel from the familiar object, indicating intact memory with an ITI of 1 h, but not 2 or 4 h. The CD delayed this natural forgetting in male rats such that discrimination was also evident after a 2 h ITI. In contrast, control females exhibited discrimination following both 1 and 2 h ITI, but the CD impaired performance. In summary, the present study shows that maternal exposure to the CD programmes NOD in the adult. In better-performing females, dietary programming interferes with NOD, whereas NOD was improved in males after lactational CD feeding.

Contemporary trends in obesity mean that research into whether unbalanced diets could impact on behavioural traits became increasingly important. The timing of exposure to obesity is particularly important, as sensitive periods during development have been identified where dietary extremes play a critical role in determining adult risk of physiological dysfunction. To this end, female Wistar rats were fed on chow or cafeteria diet (CD) for 8 weeks from weaning until mating. Half of the mated animals within each group were crossed-over to the alternative diet. This generated four treatment groups, differing in their pre-gestational and gestational diets. After birth, offspring of dams from each of the 4 pregnancy groups were further divided into groups, either being fed chow or CD throughout lactation. Anxiety-related behaviour and exploration in the offspring were tested in the Elevated Plus Maze (EMP) and the Open Field (OF) at 10 weeks of age. Maternal obesity significantly reduced the EPM locomotor activity in male and female offspring and grooming in males. Lactational CD had an anxiolytic effect in male offspring as shown in the EPM (increased entries into and more time on open arms) and the OF (shorter latency to enter the centre). In both sexes, lactational CD reduced grooming upon exposure to the EPM and the OF. Post mortem analysis revealed a stimulant effect of lactational CD on adipose tissue growth. The present study demonstrates that pre-gestational, gestational and lactational maternal CD programme behaviour in the offspring with lactational CD reducing anxiety in the male offspring.

Lactational overfeeding programmes obesity in the adult rat, and also impacts on adult emotional behaviour. The present study investigated the impact of exposing the lactating female to a hypercaloric diet on structural aspects of feeding behaviour in the adult offspring as measured by the behavioural satiety sequence (BSS). Lactating Wistar rats were fed a hypercaloric cafeteria diet (CD) in addition to chow. Controls were fed on chow only. All offspring were chow fed after weaning. BSS was tested in 12–15 week old offspring. At 20 weeks of age, monoamine neurotransmitter levels were measured in selected brain regions. When exposed to a palatable 1-h test meal, offspring responded with the same latency to feed, regardless of lactational diet. Total food intake during the test was unaffected by lactational diet. Control offspring showed a normal BSS pattern. Male CD offspring displayed shorter feeding bouts (P<0.05) with an overall higher bout frequency (P<0.001) and their latency to rest was delayed (P<0.001). Overall eating frequency (P<0.05), but not duration was increased in male CD offspring. Although the transition from feeding to resting was not affected by lactational CD, CD males fed for longer at the beginning of the test meal and were more active towards the end. CD females displayed an increased number of feeding bouts (P<0.05) and they spent more time eating (P<0.05). Resting latency was delayed (P<0.05) and overall time spent resting was shortened (P<0.01). Frequency of eating was increased in the middle of the test meal. The onset of satiety as indicated by the transition point between eating and resting was delayed in CD females (P<0.001). In both sexes, hypothalamic 5-hydroxytryptamine (5-HT) was increased (P<0.05 in females, P<0.01 in males) and 5-HT turnover was reduced by lactational CD (P<0.001 in females, P<0.01 in males). Lactational CD led also to an increase in dopamine (DA) (P<0.01). Hypothalamic DA metabolism (DOPAC+HVA/DA ratio) was overall lower in females than in males (P<0.01). This study indicates a programming effect of lactational CD on feeding behaviour and brain monoaminergic neurons.