Medicinal plants exhibit colossal impact on poultry industries by improving its performance and productivity. However, some of these plants show adverse influence too by decreasing egg production percentage, egg mass, and microbiota counts. Green tea, nettle, pennyroyal, yarrow, and alfalfa in the form of seed, powder, and extract had vast potentiality to improve immunity, reduce the growth of pathogenic microbes, and improve the viable counts of lactic acid bacteria. Lavender, Alfalfa, and Nettle powder were able to improve egg yolk color. Furthermore, ginger reduced fat content in meat and increased color intensity. Flax seed increased alpha linolenic acid content in tissue, and increased n-3 fatty acid content in breast as well as thigh tissue. Physiological assessment showed that green tea, lavender, nettle, pennyroyal, and yarrow improved poultry immunity. Lavender and nettle improved internal organ traits. Interestingly, the use of flaxseed improved quail egg hatchability. Plants metabolites, particularly carvacrol and thymol showed its pivotal role as natural growth promoters by affecting growth performances, nutrient bioavailability, and immunity of broiler chickens. Additionally, in recent years, micro-encapsulation or nano-encapsulation of plant extracts and its metabolites improved growth performances of broiler chickens, thereby suggested wide utilization of this technique as a potential alternative to antibiotic growth promoters in future. This review sheds a light on beneficial as well as no adverse effects of some of the direct-fed important medicinal plants and its metabolites in poultry nutrition in order to suggest its key role in future poultry enterprise.

药用植物通过提高其性能和生产力对家禽业产生巨大影响。然而，其中一些植物也通过降低产蛋率、产蛋量和微生物群数量而显示出不利影响。种子、粉末和提取物形式的绿茶、荨麻、蓍草、蓍草和苜蓿在提高免疫力、减少病原微生物的生长和提高乳酸菌的活菌数方面具有巨大的潜力。薰衣草、苜蓿和荨麻粉能够改善蛋黄颜色。此外，生姜减少了肉中的脂肪含量并增加了颜色强度。亚麻籽增加了组织中的 α 亚麻酸含量，并增加了乳房和大腿组织中的 n-3 脂肪酸含量。生理评估表明，绿茶、薰衣草、荨麻、茴香、西洋蓍草提高了家禽的免疫力。薰衣草和荨麻改善了内脏器官的特征。有趣的是，亚麻籽的使用提高了鹌鹑蛋的孵化率。植物代谢物，尤其是香芹酚和百里酚，通过影响肉鸡的生长性能、营养生物利用度和免疫力，显示出其作为天然生长促进剂的关键作用。此外，近年来，植物提取物及其代谢物的微胶囊化或纳米胶囊化改善了肉鸡的生长性能，因此建议将该技术广泛用作未来抗生素生长促进剂的潜在替代品。