The present research aims to evaluate the influence of Zn nanoparticles (ZnO-NPs)
and/or thyme oil on the reproductive performance of rabbits during the summer season in
Egypt. Eighty female New Zealand White rabbits (20 per diet) at approximately 6 months
of age with an average live weight of 3500 g were used and divided into 4 groups as
follows: in the first group, the animals were given the basic diet without supplements
(control group). The animals in the second and third groups were fed a basal diet
supplemented with ZnO-NPs at 100 mg/kg or thyme oil at 300 mg/kg diet, respectively.
The animals in the fourth group were fed a basal meal that was supplemented with both
ZnO-NPs at 100 mg/kg and thyme oil at 300 mg/kg. Rabbits fed ZnO-NPs, thyme, or both
during heat stress showed no significant effects on TP, ALB, and GLB variables. In the
treated groups, there was a significant (P<0.05) drop in the levels of plasma triglycerides
(TG) and total cholesterol (TC). The ovulation rate, number of embryos, embryo recovery
rate, and pregnancy rate of rabbit females exposed to heat stress were significantly
increased when thyme and ZnO-NPs were incorporated into their diets. On the other hand,
the number of hemorrhagic embryos and total abnormal follicles decreased compared with
the control group. Hence, it is possible to conclude that adding ZnO-NPs and thyme oil to
rabbits' diets considerably enhanced their physiological and reproductive performance
when the rabbits were exposed to heat stress in the summer. Therefore, given the heatstressed climatic circumstances in Egypt, it could be advised to feed rabbits with ZnO-NPs
(100 mg/kg) and thyme oil (300 mg/kg diet).