Effects of dietary thymol–formic acid blend on production metrics, carcass characteristics and meat quality in turkeys

With increasing consumer demand for safe and high-quality animal protein, poultry producers are shifting towards alternative species such as turkeys to complement the chicken production and diversify the protein source. Organic acids and essential oils have been widely evaluated as sustainable growth promoters in chicken production, replacing conventional antimicrobials that pose risks of antibiotic residues and antimicrobial resistance. This study evaluated the effects of a dietary blend of thymol (crystal powdered) and formic acid on final market live weight, feed conversion ratio (FCR), carcass traits, meat quality, and sensory attributes of turkey meat. A total of 240-day-old turkey poults were randomly assigned to six dietary treatment groups (5 replicates each) with male: female ratio kept as 1:1 per replicate and reared up to 16 weeks of market age: T1 (basal diet, BD), T2 (BD + chlortetracycline, 50 mg/kg), T3 (BD + thymol 240 mg/kg + formic acid 2.5 ml/kg), T4 (BD + thymol 360 mg/kg + formic acid 2.5 ml/kg), T5 (BD + thymol 240 mg/kg + formic acid 7.5 ml/kg), and T6 (BD + thymol 360 mg/kg + formic acid 7.5 ml/kg). Production metrics dictated a significant ( p ≤ 0.001) improvement in pre-slaughter body weight and final FCR in dietary thymol-formic acid blend treatment groups (T5 and T4) over control group. Post-slaughter evaluation revealed that thymol–formic acid supplementation ( p ≤ 0.05) improved carcass yield and cut-up parts compared to the control groups (T1 and T2). Meat quality indices, including pH, water-holding capacity, extract release volume, and drip loss, were enhanced ( p ≤ 0.05) in supplemented groups. Notably, T4 and T5 exhibited superior oxidative stability ( p ≤ 0.05), reflected by the lowest TBARS values and increased antioxidant activity (ABTS + and DPPH+ assays). Sensory evaluation further demonstrated ( p ≤ 0.05) improved juiciness and overall acceptability in the T4 and T5 groups relative to the control. In conclusion, the dietary blend T5 (Thymol 240 mg/kg + Formic acid 7.5 ml/kg) was practically most effective in enhancing carcass yield, oxidative stability, and sensory quality of turkey meat, while significantly attaining heaviest market weight with improved FCR.