Abstract
The impact of zinc oxide nanoparticles (ZnO-NPs) on the pathogenesis of coccidiosis in broiler chickens was tested. A total of 160 1-day-old broiler chicks (Ross 308) were randomly allocated into 4 groups (n = 40). Group 1: unchallenged, unmedicated; Group 2: challenged, unmedicated; Group 3: challenged, supplemented with diclazuril (1 ppm); Group 4: challenged, supplemented with ZnO-NPs (20 ppm). Mixed Eimeria species (
,
, and
) of a commercial coccidial vaccine (FORTEGRA
) were used to perform the coccidial challenge by 15× of its vaccinal dose on the 14th day of age. Diclazuril and ZnO-NPs supplementation in Group 3 and 4, respectively, reduced the mortality rate due to coccidial challenge to 5.8% compared to 11.9% in Group 2. The growth performance was improved by ZnO-NPs in coccidiosis-infected group (
≤ 0.05) compared to Group 2 and was comparable to that of Group 3 (
≥ 0.05). The average oocyst count was lower in Groups 3 and 4 (7.8 × 10
and 14.3 × 10
, respectively) than in Group 2 (67 × 10
oocysts). Group 3 had a decreased gross lesion score in duodenum and caecum (
≤ 0.05) as well as jujenum and ileum (
≥ 0.05) compared to Group 2; while the average lesion scores of all intestinal parts in Group 4 were significantly decreased (
≤ 0.05). However, diclazuril was superior to ZnO-NPs in reducing caecal lesion score (
≤ 0.05). Plasma carotenoids levels were increased by diclazuril (
≥ 0.05) and ZnO-NPs (
≤ 0.05) supplementation compared to Group 2. Oxidative stress appeared on the fourth week post-challenge (pc) in Group 2 (
≤ 0.05) compared to Group 1, while the dietary supplementation with either diclazuril or ZnO-NPs numerically decreased Malondialdhyde (
≥ 0.05) and statistically increased antioxidant activity (
≤ 0.05). Both medications significantly improved the PCV%, Hb% and RBCs count on the 6th-day and 4th-week pc (
≤ 0.05) compared to Group 2, though this improvement was higher significantly in Group 4 than Group 3 on the 6th day pc (
≤ 0.05). Neither coccidial challenge nor medications had an impact on the total WBCs count as well as organ index, except Bursa of fabricious index that significantly improved by ZnO-NPs on the 4th-week pc compared to Group 2. Coccidial challenge reduced total protein and globulin levels and increased the serum alanine aminotransferase, serum cholesterol, and low-density lipoprotein levels (
≤ 0.05) compared to Group 1, while those of both medicated groups (Group 3 and 4) were comparable to Group 1 (
≥ 0.05). In conclusion, ZnO-NPs were found to be as effective as diclazuril against coccidiosis. However, further research is needed to fully comprehend its anticoccidial mechanisms.