Barley grain varieties adapted to grow under different climates of Iran (16 cultivars named Bahman, Makoeei, CB-79-10, Sahand, Reyhan03, Reyhan45, Fajer, Nosrat, Valfajer, Kavir, MB-82-12, AB-23-14, Nimrooz, Jenob, Dasht and Sahra) were provided (10 samples per each cultivars). Samples were assessed for bulk density (BD), chemical composition including organic matter (OM), crude protein (CP), ether extract (EE), acid detergent fiber (ADF), neutral detergent fiber (NDF), and soluble sugar. An in vitro gas production technique was also used to examine the effect of the cultivars evaluated on gas production parameters of the barley grains evaluated. Approximately, 200 mg of each sample was weighed into a 120-ml serum vial (n=4). Gas production was recorded at 2, 4, 6, 8, 12, 24, 36, 48, 72, and 96 h after the incubation. Data of 24 h gas production were also used to estimate the organic matter digestibility and metabolizable energy of the cultivars. Crude protein, soluble sugar, EE, ash, NDF and ADF concentrations of the barley samples investigated was on average of 108, 35, 30, 24, 238.4 and 72 g/kg, respectively; while the difference was significant (P< 0.001) among the cultivars. Dasht had the highest crude protein (CP) and the lowest NDF; while Makooei and Sahra showed the highest NDF and BD, respectively. The average of bulk density was 679 kg/m3 (from 615 to 720); there was a negative correlation between the bulk density and ADF (r = -0.77 and P< 0.001), while the correlation between the bulk density and metabolizable energy was positive (r = 0.69 and P< 0.05). Organic matter digestibility of the samples evaluated ranged from 75 to 81% (mean= 78%) and there was a significant differences (P< 0.01) among the cultivars.

Keywords