Nutritional Value Determination of Five Plants Species in Darab Rangeland Using Gas Production Technique

 This investigation was conducted to determine the chemical composition and nutritional value of five dominant plant species in the vegetative stage, namely Artemisia herba-alba, Acer monspessulanum, Amygdalus lycioides, Amygdalus scoparia, and Atriplex leucoclada, in the pastures of Rustaq and Fedami areas, Darab in April, 2020. After collecting samples, the chemical compositions of plants including Dry Matter (DM), Organic Matter (OM), Crude Protein (CP), Ether Extract (EE), Ash, Neutral Detergent Fiber (NDF), and Acid Detergent Fiber (ADF) were determined according to the standard methods. Three 12-month-old Sistani bulls weighing 277±27 kg were used for the degradation test. The CP value ranged from 5.30 (Amygdalus scoparia) to 11.72% (Atriplex leucoclada) while NDF value ranged from 52.62 (Amygdalus lycioides) to 69.05% (Amygdalus scoparia) (P <0.01). After 96 hours of incubation, the highest and lowest gas productions with values of 54.83 and 38.66 (ml/200 mg DM) were related to Amygdalus lycioides and Amygdalus scoparia, respectively. The higher values of gas production were due to lower values of ADF (38.66%) and NDF (52.62%) in Amygdalus lycioides. The highest amounts of Ca (0.28%), P (0.15%), and Mg (0.12%) were recorded in Atriplex leucoclada. Through the gas production technique, the range of organic matter digestibility (OMD), digestible organic matter in dry matter (DOMD) and metabolisable energy (ME) were varied from 36.67 to 53.27%, 34.67 to 49.11%, and 5.57 to 8.08 (MJ/kg), respectively. The highest values of OMD (53.28%), DOMD (49.11%), and ME (8.08 MJ/kg) were recorded in Amygdalus lycioides, which were significantly higher than other studied plants (P<0.01). The nutritional value of Amygdalus lycioides, Atriplex leucoclada, Acer monspessulanum, and Artemisia herba-alba, respectively, were acceptable based on their composition and digestibility. The results of this experiment showed that range plants can meet a part of the livestock nutritional requirements.