Free and Microencapsulated Essential Oils Incubated In Vitro: Ruminal Stability and Fermentation Parameters

Abstract

Essential oils (EOs) are generally considered as an alternative to antibiotics because of their antimicrobial properties. Despite their vast variety, their volatile nature poses hindrance on their use in animal feeds, which demands a high degree of stability. This study aimed at testing the susceptibility of three EOs (mixtures of EOs based on cinnamaldehyde, named Olistat-Cyn, Olistat-G, and Olistat-P) in two forms (free: fEOs; and microencapsulated: mEOs) to in vitro ruminal degradation using the Ankom DaisyII technique. The microencapsulation was made using a matrix based on vegetable hydrogenated fatty acids. Compared to the fEOs, which were completely degraded within 48 h of in vitro incubation, the mEOs showed a low ruminal disappearance. In comparison to the fermentation profile at 0 h, Olistat-G significantly decreased the pH and the total protozoa number after 48 h, while the total VFAs increased. However, the other EOs (Olistat-Cyn and Olistat-P) had no effect on the rumen fermentation parameters. In conclusion, the protection of EOs from ruminal degradation by microencapsulation was found to be very effective to ensure rumen by-pass. Among the EOs, Olistat-G was capable of changing rumen fermentation, potentially reducing methane emissions.

Effect of essential oils and aqueous extracts of plants on in vitro rumen fermentation and methane production

“…Negligible changes in pH due to GEO (Mateos et al 2013), REO (Castillejos et al 2008), and EEO (Cobellis et al 2016) have previously been reported. Decreases of pH were previously observed for CEO in vivo (Chaves et al 2008) and in vitro (Amin et al 2021). However, decreases are often related to VFA increases, not observed in the present study.…”

Effects of Essential Oil Blends on In Vitro Apparent and Truly Degradable Dry Matter, Efficiency of Microbial Production, Total Short-Chain Fatty Acids and Greenhouse Gas Emissions of Two Dairy Cow Diets

“…Essential oils (EOs) have been known to have varying chemical structures and bioactive compounds as they are extracted from different plants [ 1 ]. Essential oils are also known for their antiprotozoal and antimicrobial properties [ 2 , 3 ]. Due to their broad range of antimicrobial activities, EOs are commonly regarded as potential antibiotic replacements [ 4 ].…”

“…The inclusion of EOs in ruminant diets has been reported to have significant influence in ruminant digestion and fermentation, as well as microbial populations and methanogenesis [ 5 , 6 , 7 , 8 ]. The use of EO blends (EOBs) over single EOs has been reported to be more advantageous [ 3 ]. Friedman et al [ 9 ] reported that by combining cinnamaldehyde with eugenol, cinnamaldehyde can be preserved from heat-induced degradation.…”

“…Friedman et al [ 9 ] reported that by combining cinnamaldehyde with eugenol, cinnamaldehyde can be preserved from heat-induced degradation. The use of EOBs is often preferred as it is unlikely that a single EO has all the attributes or properties to be as effective as an antibiotic [ 3 ]. However, few studies have been carried out to evaluate the effects of different blends of EOs on in vitro rumen fermentation parameters.…”

Effects of essential oil mixtures on nitrogen metabolism and odor emission via in vitro simulated digestion and in vivo growing pig experiments

“…Owing to the highly volatile nature of EOs, they are usually microencapsulated to protect from digestion in the upper digestive tract and thus maintain their efficacy in the lower bowel 22‐24 . The concept for EO microencapsulation is to provide a physical barrier for bioactive compounds from the environment and ensure a slow and progressive intestinal release 25 .…”