Influence of Dietary Curcumin on Rumen Fermentation, Macronutrient Digestion and Nitrogen Balance in Beef Cattle

Abstract: Problem statement: Previous studies have shown that curcumin has antibacterial activity. It was hypothesized that the feeding of curcumin to ruminants may disturb rumen function and affect macronutrient digestibility and nitrogen utilization. Approach: In an experiment with Latin-square design, beef cattle were fed rations consisting of urea-treated rice straw and concentrates without or with 0.1 or 0.2% added curcumin. Indicators of rumen function, apparent macronutrient digestibility and nitrogen balance were determined. Results: Voluntary feed intake was not influenced by the addition of curcumin to the ration. Dietary curcumin raised bacterial counts in the rumen fluid, but lowered the protozoa counts. Ruminal ammonia concentrations were decreased by curcumin. The intake of curcumin did not affect apparent digestibility of dry matter, organic matter, ether extract and neutral detergent fiber, but it reduced the digestibility of acid detergent fiber. Dietary curcumin diminished fecal nitrogen excretion and raised nitrogen absorption and retention. Conclusion: This study shows that the feeding of curcumin changes the ruminal flora and nitrogen metabolism in beef cattle. The curcumin-induced stimulation of nitrogen retention may be considered as a potentially positive effect, but the observed decrease in apparent digestibility of acid detergent fiber could limit the utilization of roughage.