Potential of selected plant extracts to control severe subacute ruminal acidosis in vitro as compared with monensin.

Abstract

BACKGROUND: In recent years, researchers have become increasingly interested in developing natural feed additives that can stabilize ruminal pH and thus prevent or eliminate the risk of severe subacute rumen acidosis. Herein, 3 experiments were conducted using a semi-automated in vitro gas production technique. In the experiment (Exp.) 1, the efficacy of 9 plant extracts (1.5&#x2009;mg/ml), compared to monensin (MON; 12&#x2009;&#x3bc;g/ml), to counteract ruminal acidosis stimulated by adding glucose (0.1&#x2009;g/ml) as a fermentable carbohydrate without buffer was assessed for 6&#x2009;h. In Exp. 2, cinnamon extract (CIN) and MON were evaluated to combat glucose-induced acidosis with buffer use for 24&#x2009;h. In Exp. 3, the effect of CIN and MON on preventing acidosis when corn or barley grains were used as substrate was examined. RESULTS: In Exp. 1, cinnamon, grape seeds, orange, pomegranate peels, propolis, and guava extracts significantly increased (P&#xa0;<&#x2009;0.05) pH compared to control (CON). Both CIN and MON significantly increased the pH (P&#xa0;<&#x2009;0.001) but reduced cumulated gas production (P&#xa0;<&#x2009;0.01) compared to the other treatments. In Exp. 2, the addition of CIN extract increased (P&#xa0;<&#x2009;0.01) pH value compared to CON at the first 6&#x2009;h of incubation. However, no significant differences in pH values between CIN and CON at 24&#x2009;h of incubation were observed. The addition of CIN extract and MON decreased (P&#xa0;<&#x2009;0.001) lactic acid concentration and TVFA compared to CON at 24&#x2009;h. The CIN significantly (P&#xa0;<&#x2009;0.01) increased acetate: propionate ratio while MON reduced it. In Exp. 3, both CIN and MON significantly increased (P&#xa0;<&#x2009;0.05) ruminal pH at 6 and 24&#x2009;h and reduced lactic acid concentration at 24&#x2009;h compared to CON with corn as substrate. However, CIN had no effect on pH with barley substrate at all incubation times. CONCLUSIONS: It can be concluded that CIN can be used effectively as an alternative antibiotic to MON to control ruminal acidosis when corn is used as a basal diet.