Effects of Oral Myrtus communis L. Extract on Serum IgG, Growth Hormone, Oxidative Status, and Serum Biochemistry in Weaned Ramlıç Lambs.

This study evaluated the effects of Myrtus communis L. extract on growth performance, growth hormone (GH), humoral immune response, oxidative stress indicators, and serum biochemical parameters in weaned Ramlıç lambs. Forty-five clinically healthy male lambs were allocated to three groups: control (n = 9), 0.5 mL/kg extract (n = 18), and 1 mL/kg extract (n = 18). The extract was administered orally once daily for 45 days. Body weight measurements and blood sampling were performed on days 0, 15, 30, and 45. Serum samples were analyzed for GH, IgG, total antioxidant status (TAS), total oxidant status (TOS), and selected biochemical parameters, whereas oxidative stress index (OSI) was calculated from TAS and TOS values. Longitudinal effects of dose, sampling day, and their interaction were evaluated using a linear mixed-effects model. Although body weight increased in all groups, no significant differences were detected among the groups (p > 0.05). A significant day × dose interaction was observed for GH (p = 0.004). IgG concentrations were significantly higher in the 1 mL/kg group on day 30 and in both extract-treated groups on day 45 than in controls. Extract administration did not cause significant changes in TAS, TOS, OSI, liver enzymes, renal function parameters, glucose, or lipid profile. In conclusion, M. communis extract was biochemically well tolerated and was associated with increased serum IgG concentrations but did not exert a marked effect on growth performance or systemic oxidant-antioxidant balance. Further studies under different physiological conditions and with longer administration periods are needed to clarify its mechanisms of action and potential use in ruminant husbandry.