Triterpenes from Olea europaea modulate in vitro ruminal fermentation

Area of Science:

• Rumen microbiology and fermentation
• Animal nutrition and feed additives
• Natural product chemistry

Background:

• Olive triterpenic acids (TT), including oleanolic acid (OA), ursolic acid (UA), and maslinic acid (MA), exhibit antimicrobial properties.
• These compounds are explored as alternatives to conventional coccidiostats in animal feed.
• Understanding their impact on in vitro ruminal fermentation is crucial for evaluating their efficacy.

Purpose of the Study:

• To evaluate the effects of OA, UA, and MA on in vitro ruminal fermentation parameters.
• To compare the efficacy of OA, OA-NA, and OA-PHYT against monensin (MON) as a positive control.

Main Methods:

• Two experiments using randomized complete block designs with bahiagrass hay or a high-concentrate diet.
• Experiment 1: Batch cultures with increasing doses of OA, UA, or MA.
• Experiment 2: Batch cultures with OA-NA or OA-PHYT at various doses to assess solubility effects.

Main Results:

• OA reduced methane (CH4) concentration in high-concentrate substrate (Exp. 1).
• OA-NA linearly decreased total gas production and in vitro organic matter digestibility in bahiagrass substrate (Exp. 2).
• OA-NA and OA-PHYT reduced digestibility similarly to MON, but CH4 reduction required higher OA-NA doses. No significant effects on total volatile fatty acids (VFA) or VFA profile were observed, except for a decreased A:P ratio with OA-NA.

Conclusions:

• Oleanolic acid (OA) and its derivatives (OA-NA, OA-PHYT) can modify ruminal fermentation parameters in vitro.
• The magnitude of these effects was generally lower compared to monensin.
• Further in vivo studies are needed to confirm if these in vitro findings translate to improved animal production efficiency and reduced carbon emissions.