Effect of water supplementation with Eurycoma longifolia (Tongkat Ali) root extract on growth performance, carcass characteristics, antioxidant responses, and gene expression in brown and white Japanese quails

The impact of varying doses of water-soluble E. longifolia root extract was evaluated on growth performance, blood biochemistry, antioxidant enzymes, histology, and expression of some related genes in brown- and white-feathered Japanese quails. Seven hundred and twenty 2-wk old quails (360 brown- and 360 white-feathered quails, 180 males and 180 females each) were randomly assigned to 8 treatments with 3 replicates having 30 quails per replicate (15 females and 15 males from the same quail’s variety). The E. longifolia was incorporated in drinking water at 0, 125, 250, and 500 mg E. longifolia/L for treatment 1, 2, 3, and 4, respectively. This experiment lasted for 4 wk. Drinking water with E. longifolia, especially at 125 mg E. longifolia/L increased body gains and feed consumption as well as gain-to-feed ratio (linear; quadratic, cubic, P < 0.05) with brown females, compared to brown males and both sex of white-feathered quails, displayed greater improvement. Growth-related genes: growth hormone receptors and insulin growth factor-1, and ghrelin mRNA concentrations were upregulated while leptin mRNA copies were reduced with E. longifolia (linear; quadratic, cubic, P < 0.001). Increasing the dose of E. longifolia reduced water consumption (linear, P < 0.001). The brown-feathered quails drank more water compared to the white-feathered ones, especially with increasing the E. longifolia supplementation rate (P = 0.004). E. longifolia also caused distinct improvement of quails’ immunity manifested by a reduced heterophils-to-lymphocytes ratio (quadratic, P = 0.005) and increases in the superoxide dismutase (cubic, P = 0.015), catalase and glutathione peroxidase enzyme activities and their mRNA copies (linear; quadratic, cubic, P < 0.001). Additionally, E. longifolia supplementation caused increases in cholesterol concentrations in white-feathered females and males and brown females while increased triglycerides concentrations, particularly at 125 mg/L in all quails except in brown female, E. longifolia reduced its concentration (quadratic, cubic, P < 0.05). Increasing supplementation dose to 500 mg E. longifolia/L lowered these concentrations compared to the lower doses. Incorporating E. longifolia also caused increases in the intestinal villi lengths (linear, P < 0.001; quadratic, P < 0.05) with fat vacuolation in hepatic tissue. Moreover, reduction in estrogen (linear, P < 0.001) and changes in testosterone concentrations (quadratic, P < 0.05) were measured with E. longifolia treatment. In conclusion, E. longifolia root extract could be used as a potential alternative osteogenic herbal additive to enhance bird’s performance. Its impacts in quail’s drinking water significantly depended on quail variety, and sex. `