Abstract
The paper investigated the phytochemical content and antioxidant activity of poplar buds (Populus nigra L.), turmeric (Curcuma longa) and ginger (Zingiber officinale) extracts. Proximate composition, total polyphenols, ß-carotene, vitamin E, minerals and antioxidant capacity were tested for all selected plants. The proximate analysis of selected plants showed that poplar buds had a higher content of crude protein, fat and fiber than turmeric and ginger. The extract of poplar buds had a significantly higher content of total polyphenols (87.20 mg of gallic acid/g) and vitamin E (210.53 μg/g) than in the extract of turmeric and ginger. The polyphenol content was found to be in the order: poplar buds>turmeric> ginger. The beta carotene content was significantly higher in poplar buds (2.99 μg/g) than in turmeric (1.67 μg/g). Regarding mineral content, turmeric showed the highest content in iron and copper; ginger showed the highest content in manganese and poplar buds had the highest content in zinc. Moreover, poplar buds possessed the highest antioxidant capacity both on vitamin C and E calibration curve, evidencing the rich content in such antioxidants. Therefore, based on the valuable nutritional composition confirmed through this study, poplar buds, turmeric and ginger can be recommended as phytogenic feed additives for poultry nutrition.