Effects of Phytogenic Feed Additives on Growth, Antioxidant Status, and Meat Quality of Broiler Chickens Under Nigerian Conditions

This study evaluates the effects of phytogenic feed additives (plant-derived antimicrobials and antioxidants) on growth performance, oxidative stress markers, and breast meat quality of broiler chickens under Nigerian tropical production conditions. The global ban on antibiotic growth promoters and rising consumer preference for natural production systems have created strong demand for phytogenic alternatives. Essential oil blends from thyme, oregano, and rosemary have demonstrated efficacy in temperate conditions, but their performance under Nigerian heat stress conditions has not been adequately characterised. This study uses a completely randomised design with five dietary treatments: no additive control, synthetic antioxidant (BHA-BHT at 200 milligrams per kilogram), and three commercial phytogenic products (thyme-cinnamon blend, oregano-garlic blend, and a proprietary multi-herb extract) at manufacturer-recommended inclusion rates. Two hundred and twenty-five Ross 308 broilers in groups of 45 are fed treatments from day 1 to 42. Growth parameters, serum malondialdehyde, superoxide dismutase, and total antioxidant capacity are measured at 21 and 42 days. Breast meat oxidative stability, colour, pH, water holding capacity, and sensory scores are measured after slaughter and 7-day refrigerated storage. Findings reveal that the oregano-garlic phytogenic blend achieves body weight gain and feed conversion equivalent to the synthetic antioxidant control, while significantly reducing serum malondialdehyde by 32 percent and improving breast meat TBARS values after storage. The thyme-cinnamon blend shows intermediate results. The study contributes original phytogenic data for Nigerian broiler conditions and recommends the oregano-garlic blend as the most effective natural growth promoter alternative.

Keywords: phytogenic additives, broiler performance, antioxidant status, meat quality, Nigeria.