Effect of Garlic Oil and Four of its Compounds on Rumen Microbial Fermentation

Abstract

Different concentrations (3, 30, 300, and 3000 mg/L of culture fluid) of garlic oil (GAR), diallyl sulfide (DAS), diallyl disulfide (DAD), allicin (ALL), and allyl mercaptan (ALM) were incubated for 24 h in diluted ruminal fluid with a 50:50 forage:concentrate diet (17.7% crude protein; 30.7% neutral detergent fiber) to evaluate their effects on rumen microbial fermentation. Garlic oil (30 and 300 mg/L), DAD (30 and 300 mg/L), and ALM (300 mg/L) resulted in lower molar proportion of acetate and higher proportions of propionate and butyrate. In contrast, at 300 mg/L, DAS only increased the proportion of butyrate, and ALL had no effects on volatile fatty acid proportions. In a dual-flow continuous culture of rumen fluid fed the same 50:50 forage:concentrate diet, addition of GAR (312 mg/L), DAD (31.2 and 312 mg/L), and ALM (31.2 and 312 mg/L) resulted in similar changes to those observed in batch culture, with the exception of the lack of effect of DAD on the proportion of propionate. In a third in vitro study, the potential of GAR (300 mg/L), DAD (300 mg/L), and ALM (300 mg/L) to decrease methane production was evaluated. Treatments GAR, DAD, and ALM resulted in a decrease in methane production of 73.6, 68.5, and 19.5%, respectively, compared with the control. These results confirm the ability of GAR, DAD, and ALM to decrease methane production, which may help to improve the efficiency of energy use in the rumen.

In vitro–in vivo study on the effects of plant compounds on rumen fermentation, microbial abundances and methane emissions in goats

“…This was also observed for the gas production rate and might suggest that at that level of dosage the fermentation was not compromised. Indeed, the DNDF was only significantly affected by CAR and PTS with a reduction of 28% in both cases, which is consistent with values reported using other garlic compounds and essential oils in vitro (Busquet et al, 2005). Although a possible overestimation of the in vitro method to estimate digestibility based on NDF residue has been reported (Getachew et al, 2004), this method is accepted for comparative purposes; nevertheless, these results need to be confirmed in vivo in producing animals with faster passing digesta rates than the 72 h used in this in vitro assay.…”

“…Animals were cared for by trained personnel in accordance with the Spanish guidelines for experimental animal protection (Royal Decree No. 1201/2005 and the European Convention for the Protection of Vertebrates used for Experimental and other Scientific Purposes (European Directive 86/609). All the experimental procedures involved in this study were approved by the Animal Welfare Committee at the Institute of Animal Nutrition (CSIC, Spain).…”

“…The increase in this ratio has been reported previously for different essential oils such as EUG, CIN and CAR (Macheboeuf et al, 2008;Mateos et al, 2013), whereas the lowered acetate to propionate ratio observed here for PTS and PTSO has been reported for different organosulphour compounds such as allicin, diallyl disulphide and allyl mercaptan (Hart et al, 2008). This different effect on the fatty-acid profile might be a consequence of the distinct modes of action exhibited by each compound: essential oils seem to have a broader antimicrobial activity by affecting the membrane integrity and disturbing energy metabolism in the cell, wherea organosulphour compounds such as thiosulphinates specifically inhibit the growth of archaea by affecting the synthesis of their glycerol containing lipids in membranes (Busquet et al, 2005). In Experiment 2, as discussed above, the selection of doses was made trying to cover the dosage window to maximize the effects without compromising overall fermentation.…”

Feeding Raw Garlic to Dairy Goats: Effects on Blood Metabolites and Lactation Performance

“…Bergman [17] estimated that 27% to 55% of the glucose metabolized by ruminants originates from propionate (as an energy precursor). Previous studies documented the lower acetate, the greater propionate and butyrate proportions and resulting lower acetate to propionate ratio in garlic supplemented diet suggested that garlic constituents might help to improve the efficiency of energy utilization in the rumen [3,4,18] . This may explain to some extent how garlic can improve serum glucose concentration.…”

“…defaunation, decreased methane production, decreased ruminal degradation of dietary proteins, reducing the proportion of acetate and increasing that of propionate) and consequently on animal production and performances [2][3][4][5] . The hypothesis addressed in this paper was that dietary addition of raw garlic would lead to efficacy of food utilization and improving in energy related blood metabolites, which would be reflected by increases in milk production and changes in milk composition.…”