Chronic fat consumption affects metabolic aspects of murine physiology and influences ovarian follicle atresia.

Saturated fat has been linked to cardiovascular diseases, leading to an increase in polyunsaturated fat consumption. The aim of the present study was to investigate the effects of three fat sources (coconut oil, lard and soybean oil) on metabolic and reproductive parameters in heterogenic mice. Female Swiss mice (5-6 weeks old; n = 9/group) were divided into four experimental groups: control (CC), coconut oil (CO), lard (LA), and soybean oil (SO), and were orally given 0.6 mL of the corresponding fat daily for 6 weeks to further investigate morphological, biochemical, and molecular parameters. SO females showed the highest glucose intolerance (P < 0.05), and all experimental groups were highly insulin resistant, with no statistical differences among them (P > 0.05). Moreover, all fat supplemented groups presented increased proportion in bile ducts, and CO and SO females presented higher LDL-cholesterol levels compared to CC (P < 0.05). Regarding reproductive parameters, estrous cycle alterations were observed mainly in the SO group, showing extended luteal phase duration (longer diestrus), and higher numbers of atretic follicles per area compared to the CC females (P < 0.05). Furthermore, higher proportion of active Casp-3 positive cells in the granulosa layers of preantral follicles were observed in the LA compared to the CO group (P < 0.05). The gene expression data revealed downregulation of Igf1r and Acvr1 in SO, upregulation of Igf1r in LA and Lhcgr in CO compared to CC females (P < 0.05). Thus, excessive fat intake may have deleterious effects on metabolism and reproductive function, but lard may be the least harmful source.