RESUMEN
Conjugated linoleic acid (CLA) is a mixture of positional isomers of linoleic acid found in ruminant products and meat. The diet supplementing with CLA is an emerging area, requiring studies to elucidate its effects on animals and human reproduction, as well as its side effects. Therefore, the aim of this study was to evaluate the effects of CLA gastric administration, during the pregestational and gestational period in biometric and reproductive parameters, as well as in ovarian morphophysiology. Animals were distributed in three groups: (1) control (n = 10); (2) fish oil (n = 10); and (3) CLA (n = 10), that daily received, by gavage, phosphate-buffered saline, fish oil and CLA, respectively, carried out over 50 days (before mating, mating and pregnancy). There was an increment in the nasoanal distance and Lee index of the CLA and fish oil-treated groups during the first weeks (P > 0.05). CLA administration did not affect the ovarian follicle mobilization (P > 0.05), the number of follicles (P > 0.05) and the integrated density of lipid content of oocytes included in antral follicles (P > 0.05). There was no effect of CLA administration on the litter weight (P > 0.05; F2 and F3), however, an increment (P < 0.05) in the number of pups per litter (F2) was observed. Overall, this study demonstrated the absence of side effects of the CLA gastric administration on mice reproductive performance and suggests that this treatment would transgenerationally enhance fertility in this species.