Garlic oil reduces ruminal fatty acid biohydrogenation in vitro

Abstract

Nutritional policies recommend that animal products should be made to contain more polyunsaturated FA, especially n‐3 FA. This means finding ways to limit ruminal lipolysis and/or biohydrogenation. In pursuit of this goal, we performed an in vitro study to test the ability of four feed additives, typically used for other purposes, to reduce ruminal biohydrogenation of a linolenic acid‐rich substrate. The four additives tested were cinnamon essential oil, brown algae (Ascophyllum nodosum), synthetic vitamin E, and garlic essential oil. The first three additives had no effect on ruminal fermentation and biohydrogenation. Garlic essential oil led to a decrease in methane production (P < 0.001), an increase in propionate (P = 0.002) and butyrate (P < 0.001) production at the expense of acetate (P < 0.001), and a decrease in biohydrogenation evaluated by the disappearance of linolenic acid (P = 0.083) and linoleic acid (P = 0.008). Stearic acid proportion in FA decreased, while biohydrogenation intermediates such as C18:2t11c15 and vaccenic acid proportion increased (P < 0.001).Practical applications: Garlic essential oil emerges as a promising additive for decreasing biohydrogenation, but its efficiency needs to be confirmed in vivo in different dietary conditions, and possible side effects of the incorporation of garlic oil in diets will have to be evaluated.When garlic oil is added to a control substrate in an incubator containing rumen contents, biohydrogenation of linolenic acid (18:3c9c12c15) is reduced, and proportion of different unsaturated FA increases at the expense of stearic acid (18:0) which decreases from 71.8 to 62.2%. If this is confirmed in vivo, this may contribute to reduce saturated FA in milk and meat from ruminants.