Potentiality of oregano essential oils as a growth modulator, immune enhancer and natural antioxidative in mite infested Newzealand white rabbits

Abstract

A total of twenty four unsexed New Zealand White (NZW) rabbits, weaned at 5 weeks of age, were observed to assess the impacts of some environmental stressors like stocking density (SD) and external parasite infestation (mite) on the growth performance and some blood biochemical parameters of this growing rabbits and assess the use of Oregano Essential Oil (OEO) supplementation as an antistressor for the rabbit intensification and mite infestation problems. NZW rabbits were housed in wire cages (45 cm x 45 cm x35 cm) in groups of 2 rabbits cage-1 (low stocking density; LSD) and 4 rabbits cage-1 (high stocking density; HSD). For the two densities, NZW rabbits were fed three diets with variable OEO levels and experimentally infested with P. cuniculi for 7 weeks by the following manner, (T1) group was the control group that has 0.0 OEO level kg-1 diet without mite infestations, (T2) and (T3) group were supplemented with 200 mg OEO kg-1 diet but only (T3) group was experimentally infested with mites, while the last treatment (T4) was experimentally infested with mites and supplemented with 400 mg OEO kg-1 diet. Finally, the current study found that a low dose of OEO-based feed had a favorable influence on the growth performance of NZW rabbits kept at LSD, with apparent benefits on antioxidant defense and innate immunity status. Our results also revealed that feed conversion ratio in rabbits provided with phytogenic supplemented diets had significantly lower values than in rabbits fed other treatments, indicating that phytogenics can promote growth. As a result, the practical consequences of phytogenic inclusion in rabbit feeds include the potential to improve rabbit growth performance and feed utilization. This would allow for faster rabbit growth, which would result in increased production time at optimal density while avoiding rabbits' parasitic infestations with mite. In conclusion, the findings of this study revealed that adding OEO in a dose of 200 mg kg-1 diet enhanced feed utilisation, rabbit somatic growth and ameliorating intensification and mite infestation stress effects on NZW rabbits.