Abstract
This study evaluated the effect of Yucca schidigera (YS) extract on the physiological, reproductive, and endocrine indexes of New Zealand White rabbit does. Six-week-old rabbit does were fed a standard diet (control group) or a diet enriched with 5 or 20 g of Y powder extract per 100-kg feed mixture for 350 days. The does were artificially inseminated after induction of super ovulation. Weight gain; conception and kindling rate; viability of pups and mothers; histopathological state of liver and muscle; plasma levels of progesterone (P4), oxytocin (OT), and prostaglandin F (PGF); and the release of P4, insulin-like growth factor I (IGF-I), OT, and PGF by isolated ovarian fragments and their response to the addition of benzene were analyzed. YS extract supplementation promoted weight gain and induced histopathological changes in the liver (creased vacuolization and occurrence of fuchsinophile inclusions in hepatocytes, liver fibrosis, hyperemia, occurrence of Kupffer cells, signs of necrosis and inflammation). YS consumption was not associated with changes in muscle (occurrence of fuchsinophile inclusions and signs of atrophy, interstitial edema, and inflammation), although Y2 increased muscle vascularization. YS supplementation increased conception and kindling rates but did not affect viability of pups or adult animals. Moreover, it enhanced plasma OT and PGF levels; plasma P4 concentration was increased by low-dose YS, but decreased by high-dose YS. Cultured ovarian fragments isolated from YS-fed does released more P4 and PGF and less IGF-I than ovarian fragments of control animals. However, YS supplementation did not affect ovarian OT release. Benzene alone did not influence the release of hormones by ovaries of control does. YS supplementation induced the inhibitory effect of benzene on the release of PGF, but not on other ovarian hormones.
Collectively, these results suggest that dietary supplementation of YS extract can stimulate rabbit performance (growth and fecundity), which may be due to the promotion of P4, OT, and PGF release. It could, however, induce some pathological changes in the liver and reduce resistance of ovaries to the environmental contaminant benzene.