Abstract
The present study investigated the protective efficacy of dietary supplementation with clove essential oil (CEO), its main constituent eugenol (EUG), and their nanoformulated emulsions (Nano-CEO and Nano-EUG) against experimental coccidiosis in broiler chickens. To this aim, various parameters (oocyst number per gram of excreta (OPG), daily weight gain (DWG), daily feed intake (DFI), feed conversion ratio (FCR), serum concentrations of total proteins (TP), albumin (ALB), globulins (GLB), triglycerides (TG), cholesterol (CHO) and glucose (GLU), serum activity of superoxide dismutase (SOD), glutathione s-transferase (GST), and glutathione peroxidase (GPx)] were compared among groups receiving CEO supplemented feed (CEO), Nano-CEO supplemented feed (Nano-CEO), EUG supplemented feed (EUG), Nano-EUG supplemented feed (Nano-EUG), diclazuril supplemented feed (standard treatment, ST), or basal diet [diseased control (d-CON) and healthy control (h-CON)), from days 1-42. Chickens of all groups, except h-CON, were challenged with mixed Eimeria spp. at 14 days of age. Coccidiosis development in d-CON was associated with impaired productivity (lower DWG and higher DFI and FCR relative to h-CON; p < 0.05) and altered serum biochemistry (decreased TP, ALB, and GLB concentrations and SOD, GST, and GPx activities relative to h-CON; p < 0.05). ST effectively controlled coccidiosis infection by significantly decreasing OPG values compared with d-CON (p < 0.05) and maintaining zootechnical and serum biochemical parameters at levels close to (DWG, FCR; p < 0.05) or not different from (DFI, TP, ALB, GLB, SOD, GST, and GPx) those of h-CON. Among the phytogenic supplemented (PS) groups, all showed decreased OPG values compared with d-CON (p < 0.05), with the lowest value being measured in Nano-EUG. All PS groups showed better values of DFI and FCR than d-CON (p < 0.05), but only in Nano-EUG were these parameters, along with DWG, not different from those of ST. Furthermore, Nano-EUG was the only PS group having all serum biochemical values not different (or even slightly improved) relative to ST and h-CON. In conclusion, the tested PS diets, especially Nano-EUG, can limit the deleterious effects of coccidiosis in broiler chickens, due to anticoccidial activity and possibly their reported antioxidant and anti-inflammatory properties, thereby representing a potential green alternative to synthetic anticoccidials.