Effect of α‐cyclodextrin‐allyl isothiocyanate on ruminal microbial methane production in vitro

Abstract

The objective of the present study was to investigate the effects of α‐cyclodextrin‐allyl isothiocyanate (CD‐AI) on ruminal microbial methane production and rumen fermentation of corn starch, soluble potato starch or hay plus concentrate (1.5:1) by mixed rumen microorganisms. Diluted rumen fluid (30 mL) was incubated anaerobically at 38°C for 6 and 24 h with or without CD‐AI (0, 0.4, 0.8, 1.6 and 3.2 g/L). The pH of the medium was unchanged by CD‐AI in all substrates. The molar proportion of acetate was decreased and propionate was increased with a corresponding decrease in acetate : propionate ratio (P < 0.05). Total volatile fatty acids and butyrate were increased (P < 0.05). Ammonia‐N was decreased (P < 0.05). Except with soluble potato starch, numbers of protozoa were unchanged after 6 h. As concentration of CD‐AI increased from 0 to 3.2 g/L, fermentation of corn starch, soluble potato starch and hay plus concentrate resulted in decreased (P < 0.05) methane production of 49–100% (6 h) and 14–100% (24 h); 39–100% (6 h) and 16–100% (24 h); and 45–100% (6 h) and 17–100% (24 h), respectively. When hay plus concentrate was used as substrate, methanogenic bacteria were decreased (P < 0.05) with 0.8 g/L of CD‐AI after 6 h. Excluding the lower dose level (0.4 g/L) of CD‐AI, digestibility of neutral detergent fiber of hay plus concentrate was decreased (P < 0.05) after 24 h. A suitable level of CD‐AI could therefore be used as a supplement to inhibit methane production and improve rumen fermentation without detrimental effects on fiber digestion.

Factors affecting methane production and mitigation in ruminants

“…2005). A reduction in CH 4 production has also been observed with cyclodextrin‐allyl isothiocyanate (Lila et al. 2003), cyclodextrin‐iodopropane complex (Mohammed et al.…”

“…Organic acids such as fumarate and malate, and propionate precursor or substances acting as a sink for metabolic hydrogen have been studied extensively (Asanuma et al 1999;Lila et al 2004a;McGinn et al 2004;Newbold et al 2005). A reduction in CH4 production has also been observed with cyclodextrin-allyl isothiocyanate (Lila et al 2003), cyclodextrin-iodopropane complex , essential oils Tatsuoka et al 2008), condensed tannins (Animut et al 2008), live yeast cells and lactate-utilizing bacteria (Asanuma & Hino 2004) both in vivo and in vitro.…”

A new perspective on the use of plant secondary metabolites to inhibit methanogenesis in the rumen

“…The contribution of allyl isothiocyanate found in mustard was not known. Lila et al (2003b) reported that synthetic allyl isothiocyanate inhibited methane production. Addition of horseradish oil at 0.17-1.7 g/l in an in vitro incubation medium inhibited the methane production by 18-90% (Mohammed et al, 2004).…”

“…The synthesis of the isoprenoid units in methanogenic archaea is catalyzed by HMG-CoA reductase (Busquet et al, 2005). Another sulphurcontaining compounds, synthetic allyl isothiocyanate inhibited methane production and ruminal methanogenic archaea in vitro (Lila et al, 2003b). Feeding of cyclodextrin-horseradish oil (3.5% allyl isothiocyanate) complex to steers at 20 g/kg diet suppressed methanogens by 20% (Mohammed et al, 2004).…”

“…Tyagi and Singhal (1998) reported that mustard oil had a suppressing effect on methane production in vitro, and they explained that it was attributed to the presence of polyunsaturated fatty acids in mustard oil that acted as a hydrogen sink. Although saturation of double bonds may act as a hydrogen sink, this sink rarely accounts for a appreciable decrease in methane production (Lila et al, 2003b). The contribution of allyl isothiocyanate found in mustard was not known.…”