Maternal high-fat diet during gestation and lactation increases conditioned aversion threshold for sucrose and alters sweet taste receptors expression in taste buds in rat offspring

Abstract

Maternal high-fat (HF) diet affects offspring's metabolic phenotype. Sweet taste is an important factor in promoting appetite. In order to determine the effects of maternal HF diet throughout gestation and lactation on taste sensitivity to sucrose in rat offspring, we measured conditioned aversion threshold for sucrose by conditioned taste aversion (CTA) associated with two-bottle choice tests, and measured mRNA expression of sweet taste receptors in taste buds. In male offspring, conditioned aversion threshold for sucrose lay between 0.007 M and 0.009 M in control group, while in those with HF dams, the threshold significantly increased to be between 0.011 M and 0.02 M. In female offspring, conditioned aversion threshold for sucrose lay between 0.003 M and 0.005 M in control group, whereas maternal HF diet increased it to be between 0.007 M and 0.009 M. Maternal HF diet increased T1R2 and T1R3 mRNA expression in taste buds of male offspring, while only increased T1R2 mRNA expression in female offspring. Both male and female offspring with HF dams had lower α-gustducin mRNA expression, whereas only male offspring with HF dams had lower OB-Rb mRNA expression in taste buds. Our data suggest that maternal HF diet decreased taste sensitivity to sucrose in both male and female offspring, which may be partly due to altered expression of sweet taste receptors and related downstream pathways in taste buds.

Keywords: Conditioned aversion threshold; Conditioned taste aversion; Maternal diet; Sweet taste receptor; Two-bottle choice test.