Abstract
Simple SummaryEssential oils are an alternative for replacing antibiotics in animal feeds, but their volatile nature demands a high degree of stability. The aim of this study was to test the in vitro ruminal degradation of two different forms (free and microencapsulated) of three commercial products (mixtures of essential oils based on cinnamaldehyde, named Olistat-Cyn, Olistat-G, and Olistat-P) using an in vitro technique. The products were incubated in filter bags using an inoculum (buffer plus rumen fluid) for 48 h at 39 °C. It was found that the microencapsulation (matrix based on vegetable hydrogenated fatty acids) was efficient to protect essential oils from ruminal degradation because of the low disappearance of the microencapsulated essential oils in comparison to the free ones that were almost completely degraded. Olistat-G caused not only a significant decrease in the pH and the total protozoa number but also a significant increase in the total volatile fatty acids. As a conclusion, microencapsulation was found to be effective to ensure rumen by-pass and to be used as an additive in ruminant feeding. Among the essential oils tested, Olistat-G (mixture of cinnamaldehyde and vitamins) was capable of changing rumen fermentation, potentially reducing methane emissions.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.
Highlights
The ban on antibiotics as growth promoters in animal feeds (1 January 2006) has resulted in an increase in demand for finding alternatives that could replace them
This study aimed at testing the susceptibility of three essential oils (EOs), namely, Olistat-Cyn, Olistat-G, and Olistat-P, in two different forms, to in vitro ruminal degradation using the Ankom DaisyII technique
The ruminal stability of the EO products was assessed on the basis of their in vitro dry matter disappearance (DMD) values calculated at six different incubation times (Table 1)
Summary
The ban on antibiotics as growth promoters in animal feeds (1 January 2006) has resulted in an increase in demand for finding alternatives that could replace them. Essential oils (EOs) are volatile, aromatic plant extracts, with several antimicrobial properties such as degradation of bacterial cell walls, increase in membrane permeability, coagulation of cytoplasm, and destruction of cytoplasmic membranes and membrane proteins [2,3,4,5,6,7]. Owing to their wide range of antimicrobial properties, EOs are generally considered as potential alternatives to antibiotics [3]. Among the various EOs studied, cinnamaldehyde, thymol, and eugenol are the most commonly used in animal feeds because of their well-reported antimicrobial properties [10]
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