Effect of Defaunation on In Vitro Fermentation Characteristics and Methane Emission When Incubated with Forages

Abstract

An in vitro study was conducted to determine the effects of defaunation (removal of protozoa) and forage sources (rice straw, ryegrass and tall fescue) on ruminal fermentation characteristics, methane (CH4) production and degradation by rumen microbes. Sodium lauryl sulfate, as a defaunation reagent, was added into the mixed culture solution to remove ruminal protozoa at a concentration of 0.375 mg/ml. Pure cellulose (0.64 g, Sigma, C8002) and three forage sources were incubated in the bottle of culture solution of mixed rumen microbes (faunation) or defaunation for up to 24 h. The concentration of ammonia-N was high under condition of defaunation compared to that from faunation in all incubations (p<0.001). Total VFA concentration was increased at 3, 6 and 12 h (p<0.05~p<0.01) but was decreased at 24 h incubation (p<0.001) under condition of defaunation. Defaunation decreased acetate (p<0.001) and butyrate (p<0.001) proportions at 6, 12 and 24 h incubation times, but increased propionate (p<0.001) proportion at all incubation times for forages. Effective degradability of dry matter was decreased by defaunation (p<0.001). Defaunation not only decreased total gas (p<0.001) and CO2 (p<0.01~0.001) production at 12 and 24 h incubations, but reduced CH4 production (p<0.001) at all incubation times for all forages. The CH4 production, regardless of defaunation, in order of forage sources were rice straw > tall fescue > ryegrass > cellulose (p<0.001) up to 24 h incubation. (Key words : Defaunation, Forages, Effective degradability, Total gas, Methane emission). INTRODUCTIONThe forages make up a large proportion of the diet in ruminant production systems. The feeding of forages as energy sources to ruminants is highly depended on rumen fermentation of the fiber such as cellulose and hemicelluloses by rumen microbes (Wina et al., 2006). Rumen protozoa are metabolically active and serve a multifunctional role in metabolizing dietary nutrients through several ways (Morgavi et al., 2010). Protozoa are well known to secrete hydrolytic enzymes (Coleman, 1986) and positively contributed to 20% of fiber degradation (Dijkstra and Tamminga, 1995). In addition to their role in fiber degradation, rumen protozoa are positively related to methane (CH4) production in the rumen. Finlay et al. (1994) described a symbiotic relationship of ruminal ciliate protozoa with methanogens, which has been proved to allow an interspecies H2 transfer from ciliate protozoa to methanogens for CH4 synthesis, and the symbiotic methanogens associated with rumen ciliate protozoa may account for 37% of the total CH4 production. Some studies have shown that defuanation (removal of protozoa in the rumen) decreased CH4 production up to 10.8% (Kreuzer et al., 1986) or 24.1% (Morgavi et al., 2008) when the cattle were fed forage diets. Furthermore, it is well known that ruminants fed forage-based diets produce more CH4 than those fed high level of concentrate diets (Johnson et al, 2000).Since CH4 emission from ruminants has increasingly caused widesprea...

Nutrient composition and in vitro fermentability of corn grain and stover harvested at different periods in Goesan, a mountainous area

“…The low total VFA concentration of corn grain could be attributed to its low EDDM. As Qin et al [28] reported, VFA concentration is positively related to EDDM. Furthermore, the diet fed to Hanwoo might have changed the microflora in the rumen.…”

Sodium dodecyl sulfate improves the treatment of waste paper with rumen fluid at lower concentration but decreases at higher condition

“…3b). Eliminating protozoa from rumen fluid using SDS decreased methane production and increased carbon dioxide production from forage sources [25]. In rumen, protozoa have symbiotic relationships with methanogens.…”

Evaluation of the Nutrient Composition, In Vitro Fermentation Characteristics, and In Situ Degradability of Amaranthus caudatus, Amaranthus cruentus, and Amaranthus hypochondriacus in Cattle

“…A. cruentus and A. hypochondriacus showed increased pH values, total gas production, and ammonia-N concentration. Finally, the volatile fatty acid (VFA) concentration which reflects the major energy content of the feed or forage as the energy source for ruminants was not affected by different amaranth forages at any incubation time except at 12 h. The A. caudatus showed a higher total VFA concentration than A. cruentus and A. hypochondriacus at 12 h; however, this increase in total VFA concentration was not supported by other fermentation parameters, such as pH, gas production, ammonia-N concentration, and EDDM, which is positively related to VFA concentration [ 31 ]. Regardless of the species of the amaranth forages, the total VFA concentrations of the amaranth forages were all closely comparable with the total VFA concentration of the locally produced forages in Chungcheong province of Korea.…”