2025 Volume 71 Issue 6 Pages 552-563
Nutritional environments in the early life shape the development of neural systems involved in rewards. While the effects of maternal nutritional status on offspring feeding behavior have been studied, the impact of non-nutrient dietary components remains poorly understood. We previously reported that prenatal exposure to bonito broth (katsuo-dashi) reduces the motivation of adult offspring to consume fat. In the present study, we explored the potential molecular mechanisms underlying this phenomenon. First, we confirmed that bonito broth intake during gestation did not affect maternal nutrition or body weight, ruling out maternal undernutrition as a confounding factor for the offspring phenotype. Using fiber photometry, we determined that corn oil intake increased dopamine release in the nucleus accumbens (NAc), but the response did not correlate with motivational behavior. In control offspring, the mRNA expression of genes related to dopamine (Drd1), opioid (Oprm1, Oprk1), glutamate (Grin1), and GABA (Gabra1) signaling was upregulated in the NAc after exposure to corn oil, and the response was significantly attenuated in the gestation group. These changes in gene expression were not observed in the ventral tegmental area or in the amygdala. These findings suggest that prenatal exposure to bonito broth through the mother attenuates transcriptional responses to dietary fat in reward-related brain regions, particularly the NAc, without affecting dopamine dynamics or maternal nutrition.
