This study aimed to evaluate the antibacterial activity of zinc oxide nanoparticles (ZnO-NPs) on Staphylococcus aureus (S. aureus) isolated from layer chickens using minimum inhibitory concentration test (MIC). A total number of 120-layer chicken samples from hock joints and livers were collected under aseptic conditions from diseased and freshly dead layer chickens from different private farms in Assiut Governorate. From these 120 samples, we isolated 29 isolates of Staphylococci with a prevalence rate of 24.16%. Nineteen (65.5 %) of these 29 isolates were coagulase negative and ten (34.5 %) were coagulase positive. By PCR, the 10 coagulase positive strains (CoPS), were confirmed to be S. aureus as they have (clfA gene), while 6 isolates only were Methicillin Resistant Staphylococcus Aureus (MRSA) as they demonstrated mecA gene. Nine isolates of S. aureus demonstrated variable antibiotic sensitivity patterns in MIC test against ZnO-NPs and some selected antibiotics. ZnO-NPs showed the best antibacterial efficiency against most isolates as compared to all tested antibiotics.

The current research aimed to study clinical, hematological and pathological changes occurred due to experimentally challenged rabbits with Pasteurella multocida type A. Twelve healthy Pasteurella multocida free rabbits were divided into control and challenged groups. Rabbits of the challenged group were intra-nasally inoculated with 0.5 ml of 1x105 CFU of Pasteurella multocida type A, while rabbits of the control group were inoculated with 0.5 ml of brain heart infusion broth (BHI). Clinical signs, hematological parameters and histopathological lesions were recoded for 14 days. Rabbits of challenged group showed nasal rubbing with minimal mucus discharge, conjunctivitis and reduction in spontaneous activity, but no mortality occurred. Hematologically, there was highly significant low RBCs count with concomitant significantly reduction of PCV in challenged rabbits, but hemoglobin concentration was insignificantly low in challenged animals as compared to control. Although, there was insignificant increase of WBCs count in challenged group, neutrophils and monocytes recorded significant and highly significant high value in challenged rabbits than control, respectively. Challenged rabbits, however demonstrated highly significant lymphopenia, but other blood parameters did not show any significant differences between challenged and control rabbits. Histopathologically, challenged animals showed meningitis, congestion and degenerative changes in respiratory epithelium, bronchopneumonia, vacuolar degeneration of hepatocytes and vascular changes in heart and spleen. Conclusively, the current study verified that challenging rabbits with Pasteurella multocida serotype A was not lethal and although it was essentially pneumotropic in nature, it caused lesions in other visceral organs, which in absence of bacteremia, could be caused by bacterial endotoxin liberated during disease pathogenesis.

The present study aimed to evaluate intramuscular xylazine HCl 2% as an anesthetic for laparogastrotomy in dogs at different doses. Twenty-seven dogs were divided randomly and equally into three groups; group A received 4 mg/kg, group B, received 8 mg/kg, and group C received 14 mg/kg. Anesthetic indices, effect on physiological parameters, blood gases, and biochemical parameters were recorded. The onset was 4.00 ± 0.00, 3.50 ± 0.33, and 5.00 ± 0.33 min, and the duration was 18.00 ± 2.50, 21.00 ± 7.20, and 28.00 ± 4.30 min in the groups A, B, and C, respectively. Pedal reflex was absent in groups A and B from 5 - 30 min post-injection. Palpebral reflex was absent in all groups from 20 - 30 min post-injection. All dogs recorded a non-significant decrease in the rectal temperature, but a significant decrease in respiratory and heart rates. There was a significant increase in the PvCO2 level and significant hyperglycemia in all dogs. Dogs in groups B and C exhibited a significant decrease in PvO2. There was a significant decrease in the serum cortisol level in the group B. Creatinine level recorded non-significant decrease in the group A, while there was a non-significant increase in the group B. There was non-significant decrease in GGT levels in the groups A and C. Xylazine at dose of 14 mg/kg established a satisfactory stable anesthesia that was enough to conduct laparogastrotomy in dogs.