Changes of chemical composition to high altitude results in Kobresia littledalei growing in alpine meadows with high feeding values for herbivores

Relationships between changes of chemical composition of Kobresia littledalei growing at different altitudinal gradients on alpine meadows of the Tibetan Plateau and its nutritive values to local herbivores were investigated. Fresh herbages were sampled from altitudes of 3980, 4582 and 5100 m. Changes (P<0.05) in concentrations of malondialdehyde, chlorophyll and carotenoids in the fresh K. littledalei occurred due to growth altitude. Metabolic changes and physiological processes in the grass to the cooler environment at high altitudes resulted in increases (P<0.05) of its crude protein, amino acid, total lipid, soluble carbohydrate, protein fractions of A, B1, B2 (according to the Cornell Net Carbohydrate and Protein System), α-linolenic acid concentrations as well as in vitro dry matter digestibility by the herbivores, and decreases (P<0.05) in neutral and acid detergent fibers, lignin(sa), and some fatty acids (i.e., palmitinic, palmitoleic, stearic, oleic, linoleic acids). Physiological adaptation of K. littledalei to the harsh environment of higher altitudes results in pronounced changes of its chemical components which confers a higher nutritive value to local herbivores.