Study of commercial avocado powder intake on metabolic and reproductive aspects of C57BL/6J mice

Abstract

A maternal Mediterranean-style diet has been associated with significantly improved health outcomes. Avocados are Mediterranean-style food because they are classified as an antioxidant, fiber-rich and nutritional dense fruit. We aim to investigate the effects of commercial avocado powder (Hass variety) during pre-conception and gestation on metabolic and reproductive aspects of C57BL/6J mice dams. Female C57BL/6J mice were kept on either a control (AIN 93; control) or avocado (dextrose and sucrose replacement with 25 % commercial avocado power) isoenergetic diet for 6 weeks prior to conception and during pregnancy (n=8 per group). Body weight and dietary intake were daily recorded. At day 17 of pregnancy (d17), an intraperitoneal glucose tolerance test (IPGTT) was done. At d18, dams were euthanized by cervical dislocation. Blood was collected for lipid analysis. Maternal liver, placental and fetal weights and sexing were recorded. 1H Nuclear Magnetic Resonance metabolomics was performed in maternal liver and placenta. Pre-conception body weight was higher in avocado damns despite similar dietary intake. At d1, average weight was similar in both groups, ~21 g. Avocado diet promoted a hypolipidemic effect where dams showed a tendency to reduce triacylglycerol, total cholesterol and VLDL in 27 % and LDL in 43 %. Avocado dams presented a significant 6 % increase in the AUC in the IPGTT (P< 0.05). Body weight at E18 of avocado group was 16 % lower than the control dams (P< 0.05). Fetal, placental weights and placental efficiency were similar between groups. However, avocado diet dams had 25 % less viable fetuses and more number of reabsorption spots (P< 0.05). Liver metabolite profile from avocado dams were similar to control, except for a significant 2-fold increase in glucose and 1.6- fold increase in the fumarate:succinate ratio. Placentas from male fetuses were more susceptible to changes in metabolites compared to female’s, in both groups. Male placentas from avocado diet compared to control dams had significant increase in methionine, phenylalanine and 3hydroxybutyrate and increased glucose, lactate and glutamate contents (P< 0.09). Avocado diet female placentas from showed higher contents of AMP, IMP (P< 0.05) and lactate (P< 0.09). A significant interaction between diet and sex for choline content was found, with an increase in its content in male placenta from avocado. The hypolipidemic effect of avocado diet might have contributed to its negative effects on reproduction. Whilst placenta from both sexes seem to be energetically competent and with high availability of methyl donors.