HIGH-FAT DIET IMPAIRS MATERNAL BEHAVIOR AND OFFSPRING SOCIABILITY THROUGH ​ALTERATIONS IN THE OLFACTORY SYSTEM

A diet rich in saturated fats has been described as one of the major contributors to obesity and related health outcomes. It is therefore expected that maternal diet has a significant effect on fetal growth and development. Indeed, studies confirm the link between perinatal exposure to a high-fat diet (HFD) and various metabolic and behavioral alterations. However, the exact mechanism underlying these effects is yet to be elucidated. The aim of this study was to link HFD-induced alterations in maternal behavior with neurodevelopmental and subsequent behavioral changes in the offspring.
For this, we have employed a combination of mouse behavioral studies, MRI and microglia analysis. First, we have demonstrated that HFD-fed mothers reduced the preference towards neutral almond smell as well as pup-derived social odors - pups` urine and nest. Additionally, HFD intake increased the detection thresholds for volatile compounds, which have previously been reported to be released by young offspring. These results suggest overall attenuation of the mothers' olfactory function, which strongly contributes to deficient maternal behavior, resulting in reduced offspring survival. In addition, maternal HFD and altered maternal behavior contributed to decreased sociability of the offspring. Such behavioral alteration was mirrored by reduced volumes of specific brain areas, in particular, those involved in olfactory processing, and by increased microglial activation in the olfactory bulb. Collectively, our results suggest that maternal HFD induces olfactory impairments in both mothers and offspring, which alter maternal behaviors leading to social deficits in offspring later in life.