Utilization of steam treated agricultural by-product as ruminant feed

Shortage of animal food is a burning issue of the recent time, whereas the agricultural by-products are readily available to be used as ruminants feed. However, the low protein and digestibility are the hindrances in utilization of these low quality crop residues as a feed. In order to utilize rice straw as animal feed this study was conducted to investigate the influence of steam explosion treatment on its composition and in vitro degradability. The samples, I (untreated rice straw), II (rice straw exposed to 15.5 kgf/cm2 steam pressure for 90 sec) and III (rice straw exposed to 15.5 kgf/cm2 steam pressure for 120 sec) were prepared. The results revealed that the crude protein (CP), ether extract (EE) and acid detergent lignin (ADL) contents of rice straw were improved after treatment with steam explosion in time dependent manner (P less than 0.05). The neutral detergent fiber (NDF), acid detergent fiber (ADF) and organic matter (OM) were higher, while dry matter (DM) and ash contents were lower (P less than 0.05) in II as compared to group I and III; however, after increasing the time at same pressure these parameters decreased. Furthermore, group III showed higher concentration of propionate, acetate, butyrate, and total VFA (P less than 0.05). While, group I exhibited higher concentration of iso-butyrate and iso-valerate (P less than 0.05). The concentration of valeric acid and acetate to propionate ratio were not affected by steam explosion treatment. Moreover, group III showed the higher in vitro DM degradability, OM degradability, DNDF and gas production (P less than 0.05); while, lower DADF and pH (P less than 0.05) compared with groups I and II. These findings suggest that the steam explosion treatment at 15.5 kgf/cm2 pressure for 120 sec, may be used to enhance the nutritive value and digestibility of rice straw.