Influence of myrtle extract supplementation via drinking water on performance, blood hematology, biochemistry, and intestinal morphology in Wistar albino rats

This study aimed to evaluate the effects of <i>Myrtus communis</i> extract added to drinking water on performance parameters, blood physiology, selected biochemical parameters, and small intestinal histomorphology in rats. A total of 80 healthy 30-day-old Wistar albino rats (40 female and 40 male) were randomly assigned to control or treatment groups, each further divided into eight subgroups. The experimental groups received <i>Myrtus communis</i> extract in drinking water at concentrations of 0% (control), 2.5, 5, 7.5, and 10% for a period of 35 days. Body weight and feed intake were recorded weekly, while water consumption was measured daily. At the end of the experiment, all animals were anesthetized and euthanized; blood samples were collected by cardiac puncture, liver tissues were sampled for cytokine and heat shock protein analyses, and small intestinal tissues were collected for histopathological evaluation. Supplementation with <i>Myrtus communis</i> extract did not affect the body weight, water consumption and feed consumption. While the serum glucose level was lower in the 2.5% group; addition of the extract at the 10% concentration decreased the serum urea and blood urea nitrogen levels. The blood physiological parameters were not influenced by the treatment except for increased basophil counts in the treatment groups. Expression levels of proinflammatory cytokines, HSP70 and HSP90 were similar among the groups. The treatment significantly increased the villus length, crypt depth and Proliferating Cell Nuclear Antigen (PCNA) scores in the small intestine. In conclusion, supplementation of <i>Myrtus communis</i> extract via drinking water improved intestinal morphology and epithelial proliferative activity and modulated serum glucose levels, while exerting limited effects on systemic inflammatory markers and performance parameters. These findings suggest that <i>Myrtus communis</i> may serve as a functional phytogenic additive supporting intestinal health without compromising growth performance.