The objective of the present study was to assess the effect of dietary supplementation of oregano
leaves exctract (OLE) and its bioactive lipid compounds (BLC) as a natural feed additive on nutrient
digestibility, growth performance, and carcass traits of rabbits. A total of 48 male weaned Sinai Gabali kits
with an average live body weight of 806.24 gm were randomly divided into equal (12 kits/group) four
experimental groups. The 1st group (T1) was fed the basal diet with no additives (control). The 2nd group (T2)
was fed the basal diet supplemented with oxytetracycline antibiotic (OTC) at a level of 50 mg/ kg diet. The 3rd
group (T3) was fed the basal diet supplemented with 8 ml/kg diet OLE + 0.75 ml/kg diet BLC. The 4th group
(T4) was fed the basal diet supplemented with 12 ml/kg diet OLE + 1 ml/kg BLC. A total of nineteen active
components in OLE were identified. The highest components were Rosemarinic acid (15.590 mg/L), Hesperidin
(8.175 mg/L) and Myricetin (4.14 mg/L). The oregano BLC was mainly composed of carvacrol (14.6%), thymol
(12.7%), β-fenchyl alcohol (12.9%), and δ-terpineol (7.6%). Supplementation of different levels of OLE and its
BLC significantly improved dry matter, crude protein, and ether extract digestibility compared to the control
group. Regarding the total digestible nutrients (TDN), rabbits fed the T4 diet recorded the highest value
(78.73%), followed by the groups of T3, then T2. However, the control group had the lowest TDN (77.23%).
Final live body weight, total weight gain, average daily weight gain, and feed conversion ratio were significantly
improved with the dietary inclusion of OLE and its BLC compared with the control group. No significant
differences between the treatment and control groups in liver, heart, lung, trachea, and leg weights were
identified. However, T4 had significantly (P |
