Chemical composition and in vitro digestibility of Sesbania sesban using gas production technique during various weeks of growth in ruminant nutrition

Sesbania is a perennial legume that grows mostly in the tropics of Asia, Africa and Australia. This plant tolerates different type of soils, especially saline soils. Due to appropriate protein percentage and relatively low fiber, this plant can be used in ruminant diets. This study was conducted to determine the chemical composition and digestibility of sesbania (Sesbania sesban) using gas production technique and to evaluate the trend of changes in these parameters from the third week to ninth week of growth. The samples from whole plant, leaves and stems were collected separately at third, fifth, seventh and ninth week of planting, to measure chemical composition (dry matter, protein, ash, neutral detergent fiber and acid detergent fiber) and also in vitro digestibility by gas production technique. The results of this experiment showed that the percentage of NDF and ADF increased significantly with the growth in the whole plant, leaves and stems, so that in the whole plant the amount of NDF increased from 35.66% in the third week to 46.08% in ninth week, and ADF ranged from 22.90 in the third week to 35.43 in the ninth week. Protein concentration decreased with aging in all parts of the plant. The amount of protein in the ninth week of growth was approximately 17.38% and 21.01% in the whole plant and leaves, respectively. With increasing plant age, along with increasing the concentration of structural carbohydrates and protein reduction in all three samples (whole plant, leaves and stems), the production of cumulative gas after 48 hours, total gas production, metabolisable energy, short chain fatty acids and organic matter digestibility decreased. The results of this study showed that according to the amount of dry matter and other measured compounds, the most appropriate time to harvest this plant as a whole plant is the seventh week of cultivation and the whole sesbania or its leaves can be a good source of livestock fodder after about two months of cultivation.