The use of steam treatment for improvincg the nutritive value of roughages

The aim of this study was to investigate the effect of steam treatment on nutritive value of sugar cane bagasse. Sugar cane bagasse (SCB) was obtained from Haft-Tappeh sugar cane plant and transported to Animal Science Research Institute of Iran in Karaj. A complete randomized design with 3×5 factorial arrangement was conducted in which SCB was treated with 3 levels of pressure (14, 17 and 20 atmosphere) and 5 levels of reaction times (120, 180, 240, 300 and 360 seconds) using three replications. Effect of the pressure and reaction times on chemical compositions and bioavailability of cell wall to rumen microorganisms was studied. The results showed that pressure and reaction time significantly (p0.05) affected all the chemical compositions except EE. The NDF content was changed from 88.57% in control sample to 80.67% in the sample treated at 14 atmosphere and 120 seconds (14-20) and to 54.67% in the sample treated at 20-360. The content of ADL changed from 10.83% in control to 12.00% in the sample treated at 20-360. An increasing trend was also observed in the content of total extractable phenolics (TEP). TEP was increased from 0.06% in the control to 5.86% in the sample treated at 20-360. Results of gas test showed that all treatments produced more gas as compared to the control. Gas production was also higher in the washed samples. This shows that higher gas production is not only due to more soluble sugars but bioavailability of cell wall carbohydrates were also higher. Degradability of all treated samples in the rumen was higher compared to the control and washing loss in the sample treated at 20-360 was 7 times higher compared to control (33.58% against to 4.51%). The insoluble but degradable fraction (b fraction) in treated samples was significantly (p0.05) higher. Among the 15 treated samples, the one treated at 20-180 conditions, was chosen as the best treatment because it had higher gas production, higher degradability, and higher (b) fraction. In vivo digestibility of DM and TDN were 55.22 and 55.49% which measured by sheep and digestible energy was 2383.2 Kcal/Kg. It is concluded that steam treatment can strongly affect chemical composition of SCB and improves its nutritive value.