The Effect of Adding Mountain Mint ( Ziziphora clinopodioides Lam.) to Diet of Laying Japanese Quails on Productive Performance, Egg Quality Traits, Blood Metabolites and Immune Response

BACKGROUND: Mountain mint (MM), a traditional herbal remedy, has garnered attention for its potential benefits on poultry health and productivity. OBJECTIVES: This experiment aimed to evaluate the effects of dietary supplementation with MM on the immune response, productive performance, egg quality traits and blood metabolites of laying Japanese quails. METHODS: A total of 375 quails, aged 6 weeks, were used in a 14-week trial in a completely randomized design with 5 treatments and 5 replicates of 15 birds each. The treatments included five levels of MM powder: 0% (control), 0.2%, 0.4%, 0.6% and 0.8% of the diet. RESULTS: Adding MM to the diet had no significant effects on egg production, egg mass and weight, feed intake or feed conversion ratio. Increasing MM levels significantly decreased egg-shape index (p < 0.05). The highest egg-shape index was observed in control and 0.2% MM groups (79.9%), whereas the lowest was observed in 0.8% treatment (75.1%). MM significantly increased blood high-density lipoprotein cholesterol (HDL-C) and decreased low-density lipoprotein cholesterol (LDL-C) concentrations (p < 0.05). Highest HDL-C concentration was observed in 0.8% MM, which was significantly (p < 0.05) higher than that in the control and other treatments. Lowest LDL-C was observed in 0.4%-0.8% MM, which was significantly (p < 0.05) lower than that of control and 0.2% MM. MM linearly decreased LDL-C (p < 0.05). Dietary MM improved primary immune responses, as evidenced by higher immunoglobulin M (IgM) titres, whereas immunoglobulin G (IgG) and total anti-sheep red blood cells (SRBC) titres remained unchanged. CONCLUSIONS: Adding MM to the diet had no significant effect on productive performance, resulted in the production of elongated eggs and improved blood lipid profiles and primary immune responses in laying quails.