Harnessing natural feed additives for sustainable production and economics: The role of Thymus vulgaris, L. oil as an antimicrobial agent and growth promoter in improving production and health of broiler chickens

Mahmoud M Alagawany^1*Ahmed M. Saied¹Adel I. Attia¹Fayiz M. Reda¹Mohamed El-Kholy¹Mohammed A. Al-Badwi²Mahmoud Azzam²Alessandro Di Cerbo³Khaled A. El-Tarabily⁴Ayman G. EL Nagar⁵

• ¹Zagazig University, Zagazig, Egypt
• ²King Saud University, Riyadh, Saudi Arabia
• ³Universita degli Studi di Camerino, Camerino, Italy
• ⁴United Arab Emirates University Department of Government and Society, Al Ain, United Arab Emirates
• ⁵Benha University, Banha, Egypt

Introduction: This study examined the effects of adding thyme oil (TO) in broiler diets on growth performance, intestinal health, immune organ indices, and blood biochemical parameters as well as economic feasibility. Methods: In a completely randomized block design, five groups of one-day-old broiler chicks (n=300) with five replicates, each consisting of 12 chicks: a basal diet (BD) was supplied to the control group, while a BD plus 75, 150, 225, and 300 mg/kg of TO was given to the other groups. Results and discussion: TO improved final BW and total BWG and FCR (P<0.05), without affecting FI. The groups fed 150, 225, and 300 mg/kg of TO showed higher levels of digestive enzymes than controls (P<0.05). Moreover, total protein, globulin, immunoglobulin (IgG and IgM), lysozyme, complement 3 were significantly higher by TO at 150, 225, and 300 mg/kg than 0 and 75 mg/kg diet; while, IgA did not exhibit any statistically significant changes due to the addition of TO. Lipid peroxidation was significantly decreased by TO supplementation (150, 225, and 300 mg/kg), while superoxide dismutase (SOD), total antioxidant capacity (TAC), catalase (CAT), reduced glutathione (GSH), glutathione reductase (GST) were significantly increased by 225 and 300 mg TO /kg compared to the controls. Lower levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), and very low-density lipoprotein (VLDL) were induced by 150, 225, and 300 mg TO/kg than 0 and 75 mg/kg (P<0.05), while higher high-density lipoprotein (HDL) levels were observed by 225 and 300 mg TO/kg than the control (P<0.05). The net revenue and economic efficiency of treated broilers were improved during the experiment (1-6 wks of age) with TO supplementation; the best value was observed in the group of receiving 150 mg/kg of diet. Collectively, supplementation with dietary TO enhanced growth performance, intestinal health, immune system development and function, liver and kidney function, and antioxidant capacity, and regulates the lipid profile as well as improved economic feasibility.