Effect of oregano essential oil supplementation on performance, biochemical, hematological parameters and intestinal histomorphometry of Japanese quail (Coturnix coturnix Japonica)

This study was performed to evaluate the efficacy of two levels of dietary oregano essential oil (OEO) on growth performances, biochemical, hematological parameters and intestinal histomorphology in Japanese quail. A total of 99 quail chicks were divided into three groups (33 quails/ group); control, OEO 150 mg kg-1 and OEO 300 mg kg-1 treated groups for 42 days (d). Feed conversion ratio (FCR), feed intake, weight gain and edible organs weight were recorded. Biochemical and some hematological parameters were determined. Histomorphological examination of hepatic and intestinal tissues was performed. FCR was improved and feed intake was decreased (P<0.05) in OEO 150 mg kg-1 group than control. No detectable changes were observed in lipid profile. Meanwhile, total protein, albumin, globulin and H/L ratio were significantly (P<0.05) increased in OEO 300 mg kg-1 at 21 d. Uric acid and creatinine significantly (P<0.05) increased in OEO 300 mg kg-1 group at 42 d. A significant (P<0.05) increase in the whole thickness of small intestine in OEO 150 mg kg-1 group beside significant (P<0.05) increase in villi length, width and crypt depth. Vacuolar and fatty degeneration of the hepatocytes along with Kupffer cell hypertrophy were observed in OEO 300 mg kg-1 group. It was concluded that OEO 150 mg kg-1 improved the quail`s performance, intestinal histomorphometry as well as hematological parameters, with no negative impacts on biochemical parameters.