Impact of supplementing meat-type chickens with peppermint water extract (Mentha piperita) on lymphoid organs and some blood parameters

This study aimed to investigate the effects of peppermint (Mentha piperita) water extract supplementation on hematological, biochemical, and antioxidative parameters in meat-type chickens. A total of 72 one-day-old Ross 308 broiler chicks were randomly assigned to three groups: a control group receiving a basal diet, and two treatment groups supplemented with 0.6% (6ml /l) and 0.8% (8 ml/l) peppermint extract in drinking water for 38 days. Each group had 3 replicate pens with 8 birds. Results showed that peppermint extract significantly increased hemoglobin content, and hematocrit levels compared to the control group (P < 0.05). The addition of 0.6% peppermint exhibited significant improvements in lymphocyte percentage, serum albumin, HDL, and antioxidant markers (GPx, GSH), along with a reduction in MDA and stress indicators (H/L ratio). The 0.8% group showed higher bursa percentage and glucose reduction, but increased liver and kidney function markers (AST, creatinine). In conclusion, water peppermint extract at 0.6% improved hematological parameters, antioxidant status, and metabolic parameters, suggesting its potential as a natural feed additive for enhancing poultry health.