The influence of subcutaneous injections of silver nanoparticles (AgNPs) on rabbit performance, hematological and biochemical parameters of blood, antioxidant status, and the residues of silver in meat and blood in two breeds (New Zealand White (NZW) and Jabali) of rabbits growing under high ambient temperature was evaluated. A total of 90 six-week-old rabbits (45 NZW and 45 Jabali) were randomly distributed into three equal treatment groups (control, 0.5 mg, and 1.0 mg AgNPs/kg body weight). The treated rabbits were injected twice a week for four consecutive weeks. The results revealed that AgNPs administration had no significant effect on average daily gain (ADG), feed intake, and feed conversion ratio (FCR). The NZW breed surpassed the Jabali breed in growth performance traits, carcass weight, dressing percentage, and cuts of mid parts and hind cuts. Administration of AgNPs had a significant effect on hematocrit (HCT) and platelet (PLT) values. Rabbits injected with AgNPs at a dose of 0.5 mg showed a lower plasma concentration of total cholesterol and triglycerides than that of control rabbits. The NZW breed had significantly low platelet, total cholesterol, and triglyceride values. Rabbits injected with 0.5 mg/kg BW had the lowest total antioxidant capacity and highest malondialdehyde (MDA) and glutathione peroxidase. The Ag residues were higher in blood than those in meat in treated rabbits. The local breed (Jabali) had significantly lower residues than the imported one (NZW) either in meat or in blood. However, the amount of accumulated silver in blood plasma and meat increased with increasing dose.

This research aimed to study the effect of dietary eucalyptus ( Eucalyptus camaldulensis ) leaves powder (EL) on growth performance, blood parameters, immune response and caecal microbiota in 84 growing Jabali and V-Line rabbits raised under high environmental temperature. The experiment started at 10 weeks of age and lasted 6 weeks. Rabbits were randomly distributed into three dietary eucalyptus treatments; control (no EL) and two groups supplemented with 0.1% and 0.2% EL powder. Rabbits were weighed at the beginning and at the end of the experiment. Feed intake, weight gain and feed conversion ratio were determined. Cell-mediated immune response was evaluated. At the end of the experiment, 54 rabbits were slaughtered (nine rabbits/sub-group). The results showed that the high level of EL (0.2%) had a negative effect on growth performance, dressing %, mid part % and significantly increased cell-mediated response. Rabbits fed the high level of EL showed shortening in caecum length. Significant linear reduction of total bacterial count and E. coli was observed in both groups given either 0.1% or 0.2% EL compared to the control group. Similar trend was found in the percentage of Salmonella sp. detection in both breeds. Jabali rabbits were significantly heavier than V-line rabbits and had better FCR and carcass traits except for fore part %. Additionally, they showed lower total microbial count. The current study indicated that EL could be utilized as an effective feed additive to improve cellular immunity and to reduce caecal bacterial counts in rabbits raised under high ambient temperature.