Nutritional potential of four plant species (Arctium lappa, Verbascum thapsus, Althaea officinalis and Ferula hermonis) in Razavi Khorasan rangelands

Awareness of the nutritional value of different rangeland plants can help animal husbandries to prepare a suitable diet; hence some experiments were conducted to determine the chemical compositions, minerals, gas production and other fermentation parameters of four range plants that can be grown in Torbat-e Jam (including Arctium lappa, Verbascum thapsus, Althaea officinalis and Ferula hermonis), Iran. The above plants were randomly collected before flowering. The range of crude protein (15.85- 22.87%), ash (8.27-16.10%), crude fat (0.85-5.75%), neutral detergent fiber (19.27-37.53%), acid detergent fiber (15.53-26.53%), acid detergent lignin (3.83-5.43%), and crude fiber (12.49-21.74%) was different among four plant species. The highest amount of calcium (12.26 g/kg DM) was related to Althaea officinalis. The parameters of gas production and other fermentation parameters were also different among the plants, so that the maximum amount of gas production after 12, 24, and 48 h incubation (47.32, 61.64, 71.21 ml, respectively), potential gas production (75.70 ml), dry matter and organic matter digestibility (82.99 and 84.60 %, respectively), metabolizable energy (10.66 MJ/kg DM), net energy for lactation (6.51 MJ/kg DM), and total volatile fatty acids (36.62 mmol/L) were found in Verbascum olympicum. There was a negative correlation coefficient between the gas produced after 24 h incubation with ether extract, crude protein, and ammonia nitrogen. Comparison of the gas production, fermentation and degradability parameters among studied plants indicated that Verbascum thapsus had higher potential nutritive value.