Ruminal methane inhibition potential of various pure compounds in comparison with garlic oil as determined with a rumen simulation technique (Rusitec)

• Published in: British journal of nutrition 2011-07, Vol.106 (1), p.114-122
• Main Authors: Soliva, Carla R., Amelchanka, Sergej L., Duval, Stéphane M., Kreuzer, Michael
• Format: Article
• Language: English
• Subjects: additives; Allyl Compounds - pharmacology; allyl isothiocyanate; Animals; Bacteria - drug effects; barley; Biological and medical sciences; chenodeoxycholic acid; diet; Dietary supplements; emissions; Feeding. Feeding behavior; Fermentation; Fermentation - drug effects; Fundamental and applied biological sciences. Psychology; garlic; hay; Incubation; levulinic acid; Lolium; lovastatin; Methane; Methane - metabolism; methane production; Microbiology; Models, Biological; neutral detergent fiber; Nutrition research; Oils & fats; plate count; rumen; Rumen - physiology; ruminants; Simulation; soybean meal; Sulfides - pharmacology; Vertebrates: anatomy and physiology, studies on body, several organs or systems
• ISSN: 0007-1145; 1475-2662
• DOI: 10.1017/S0007114510005684

Ruminants represent an important source of methane (CH4) emissions; therefore, CH4 mitigation 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 H2 and CH4 formation were determined. Garlic oil, allyl isothiocyanate, lovastatin and the synthetic compound APEE decreased the absolute daily CH4 formation by 91, 59, 42 and 98 %, respectively. The corresponding declines in CH4 emitted 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 CH4 without noticeably impairing microbial nutrient fermentation. Other promising substances were allyl isothiocyanate and lovastatin.