Feeding additive <i>Mosla chinensis</i> Maxim. essential oil modifies the growth performance, antioxidant indices, and meat quality of yellow-feathered chickens

Phytogenic essential oils are increasingly recognized as feed additives capable of enhancing performance and physiological resilience in poultry. This 52-d study evaluated the effects of dietary supplementation with graded levels of Mosla chinensis Maxim. essential oil (EO) on growth performance, antioxidant status, immune-related indices, meat quality, and cecal microbiota in yellow-feathered chickens. A total of 1,008 one-day-old chicks were randomly assigned to 7 treatments with 6 replicate pens per treatment (24 birds/pen): a basal diet (negative control), a basal diet supplemented with 200 mg/kg oregano essential oil (positive control), and basal diets supplemented with EO at 40, 80, 160, 320, or 640 mg/kg. Data were analyzed by one-way ANOVA, with orthogonal polynomial contrasts used to assess linear and quadratic dose-response relationships; significance was declared at P < 0.05. During d 1-21, dietary EO at moderate levels (80-160 mg/kg) increased body weight (BW) at d 21 from 312.2 g (control) to 334.9 g (EO80) and 347.6 g (EO160), and reduced F/G from 1.74 (control) to 1.62 (EO80-EO160) (P < 0.05). Over the entire 52-d period, F/G was lower in EO groups than in the control (control: 2.36 vs. EO160: 2.25; P < 0.01). At d 52, plasma MDA was lower in EO80 than in the control (1.21 vs. 2.24 nmol/mL; P < 0.05) and T-AOC was higher (11.65 vs. 8.11 U/mL; P < 0.05). T-SOD and GSH-Px activities were also improved at moderate doses in both plasma and jejunal mucosa (P < 0.05). Breast meat quality was improved at d 52: shear force was reduced (control: 24.15 vs. EO320: 18.01 N; P < 0.05) and TVB-N was lower (control: 11.81 vs. EO80: 9.79 mg N/100 g; P < 0.05). Drip loss was also reduced at moderate doses (P < 0.05). Furthermore, EO supplementation modulated cecal microbiota composition, notably enriching genera associated with beneficial fermentation at intermediate doses. Dietary EO at 80 to 160 mg/kg was associated with improved feed efficiency, antioxidant defense, meat quality, and gut microbial profiles in yellow-feathered chickens under the present experimental conditions.