Developmental consequences of in-utero exposure to omega- 9 monounsaturated fatty acid and its sex-skewing potential in rats

Abstract

Background: A lot of studies have described the effects of polyunsaturated fatty acids (PUFA) on fecundity and foetal development in experimental animals and in man. There is dearth of information on the effect of in-utero exposure to monounsaturated fatty acids on pregnancy outcomes and foetal development in rats. Methods: Omega-9 (Oleic acid) was administered by oral gavage at a no-observed-adverse effect level (NOAEL) according to OECD guidelines.  Gravid dams (190-220g, n=25) were distributed into five groups of five rats each; F0C: control group was administered 1ml/kg of olive oil, F0_EXBM was administered 1000mg/kg of oleic acid for 7days before mating, F0_GD1-7 was administered 1000mg/kg of oleic acid between gestation day (GD)1-7, F0_GD8-15 was administered 1000mg/kg of oleic acid between GD8-15, F0GD1-21 was administered 1000mg/kg of oleic acid between GD1-21. Gestation length, litter size, offspring anogenital index (AGI) and developmental landmarks were observed. Data were analysed using ANOVA. Results: There was a significant increase in gestation length in the F0_EXBM, F0_GD8-15, and F0GD1-21 groups compared with the F0_C. Litter sizes were significantly reduced in the F0_EXBM, F0_GD1-7, F0_GD8-15 groups when compared with F0_C (p< 0.01).  The offspring anogenital index on postnatal day 4 was significantly reduced when compared with control. Mortality was observed in all the three offspring born to the F0_GD1-21 group.   Conclusion: Oleic acid has negative effects on pregnancy outcome and foetal development although dams exposed to oleic acid had a shift in offspring sex ratios favouring males.