Abstract—In a four-month feeding experiment, 32 growing female rabbits (Oryctolagus cuniculus) of an average weight of 1366.56±37.54 g were used to evaluate the inclusion of different dietary concentrations of cerium oxide (CeO) on fertility and post-partum performance of animals. The animals were randomly allotted to four dietary groupssupplemented with 0, 100, 200 and 300 ppm CeO, each consisting of eight animals and were fed for eight weeks before mating. At the end of the 1^st trimester, 16 out of the 32 mated does were sacrificed and their uteri cut open and the remaining 16 pregnant does were raised to full gestation to evaluate the fertility and post-partum parameters, respectively. The results revealed that the dietary REE, especially at 200 ppm/kg feed significantly (P<0.05) increased the litter size, litter weight, total litter weight, embryo survival rate, average litter size and weight post−partum except for the conception rate, gestation length, foetal crown-rump length and embryo weight that were not significantly (P>0.05) influenced. Dietary REE is therefore capable of enhancing fertility in rabbits particularly at 200 ppm/kg feed and at the same time reduce mortality in kittens by 20.88 - 68.01 % and 34.14 - 45.10 % at 100-200 ppm/kg feed.

Index Terms—cerium oxide, fertility, rabbit, Rare earth element, reproduction