Author:
Soliva Carla R.,Amelchanka Sergej L.,Duval Stéphane M.,Kreuzer Michael
Abstract
Ruminants represent an important source of methane (CH4) emissions; therefore, CH4mitigation by diet supplementation is a major goal in the current ruminant research. The objective of the present study was to use a rumen simulation technique to evaluate the CH4-mitigating potential of pure compounds in comparison with that achieved with garlic oil, a known anti-methanogenic supplement. A basal diet (15 g DM/d) consisting of ryegrass hay, barley and soyabean meal (1:0·7:0·3) was incubated with the following additives: none (negative control); garlic oil (300 mg/l incubation liquid; positive control); allyl isothiocyanate (75 mg/l); lovastatin (150 mg/l); chenodeoxycholic acid (150 mg/l); 3-azido-propionic acid ethyl ester (APEE, 150 mg/l); levulinic acid (300 mg/l); 4-[(pyridin-2-ylmethyl)-amino]-benzoic acid (PABA, 300 mg/l). Fermentation profiles (SCFA, microbial counts and N turnover) and H2and CH4formation were determined. Garlic oil, allyl isothiocyanate, lovastatin and the synthetic compound APEE decreased the absolute daily CH4formation by 91, 59, 42 and 98 %, respectively. The corresponding declines in CH4emitted per mmol of SCFA were 87, 32, 40 and 99 %, respectively, compared with the negative control; the total SCFA concentration was unaffected. Garlic oil decreased protozoal numbers and increased bacterial counts, while chenodeoxycholic acid completely defaunated the incubation liquid.In vitro, neutral-detergent fibre disappearance was lower following chenodeoxycholic acid and PABA treatments ( − 26 and − 18 %, respectively). In conclusion, garlic oil and APEE were extremely efficient at mitigating CH4without noticeably impairing microbial nutrient fermentation. Other promising substances were allyl isothiocyanate and lovastatin.
Publisher
Cambridge University Press (CUP)
Subject
Nutrition and Dietetics,Medicine (miscellaneous)