• Journal of Life Science
• /
• v.18 no.4
• /
• pp.515-521
• /
• 2008

This experiment was conducted to investigate effects of non-ionic or zwitterionic (+/-) surfactants on digestibility of rice straw, and changes of growth of rumen mixed microbes, pH, and gas production during in vitro fermentation. Also, during in vitro ruminal fermentation, microbial attachment on rice straw was investigated using scanning electron microscopy (SEM). Tween 80 or SOLFA-850 for non-ionic surfactant (NIS), and 3-(Dodecyldimethylammonio) propanesulfanate (DDAP) for zwitterionic surfactant (ZIS) was supplemented by 0.05% and 0.1% in Dehority's artificial medium containing Holtein rumen fluid, respectively, and the substrate for fermentation was rice straw passed through 1 mm screen. The experiment was composed of 7 treatments (two levels of two NISs, two levels of a ZIS) including the control, and 6, 12, 24, 48 and 72 hr of fermentation time with 3 replications per treatment. Treatment of Tween 80 increased in vitro DM digestibilities during 48 hr and 72 h post fermentations compared to the other treatments, whereas treatment of DDAP as a ZIS resulted in decreased DM digestibility than that of the control from 24 hr post fermentation (P<0.05). Gas production in vitro was greater (P<0.05) with addition of NIS than the control or ZIS, and increased as fermentation time elapsed. Rumen mixed microbial growth was greatest with addition of Tween 80 as NIS, and lowest when DDAP as ZIS was supplemented to the fermentation tube (P<0.05). In SEM observation, rumen microbial population attached on rice straw particle was greater with addition of NIS, but was less with addition ZIS compared with the control. In conclusion we could not found any positive effects of ZIS surfactants on rumunal fermentation characteristics and rumen microbial growth rates.