ISSUE FOCUS 52 FEED & ADDITIVE MAGAZINE May 2024 Throughout its history, synthetic feed-grade Vitamin E acetate has been known for its (high) price volatility combined with a global supply chain prone to disruptions. Polyphenol-rich natural extracts, on the other hand, have a rather high stability in cost. However, not all types of polyphenolic antioxidants are readily bio-available to the animal and thus suited to partially substitute Vitamin E for feed cost reduction. Luckily, reliable assays become increasingly disposable to evaluate a product’s true antioxidant capacity in animal cells. Vitamin E (VE) is applied in feed for a dual purpose. Firstly, for its unique bio-essential functions for the animal regarding immunity, reproduction, preservation of cell membranes, etc. Secondly, as a standard antioxidant with a high biological activity in the animal, thanks to its phenolic structure (Figure 1) and beneficial reduction potential. The latter implies it’s an effective scavenger of oxidising agents (i.e. free radicals) in the animal’s body. The most widely used type of VE in premixes and compound feed is the synthetic form all-rac-DL-α-tocopheryl acetate 50% Adsorbate. This is an ester of α-tocopherol and acetic acid, being stable during storage and handling. Within the animal’s body, it is converted into highly bio-available free tocopherol via a necessary hydrolysis step. BIOACTIVE ANTIOXIDANT ALTERNATIVES TO VITAMIN E Vitamin E acetate is known for its typical price volatility and riskful global supply chain that can lead to supply disruptions. Consequently, more and more formulators are replacing the antioxidant part of synthetic VE’s dosage in the premix or compound feed by natural polyphenols. It is crucial to stress that, in the animal, polyphenols can only substitute the antioxidant properties of dietary VE and not its essential vitamin functions. Polyphenols are a diverse group of more than 8,000 phytobiotic compounds, occurring in almost every plant. Plants like tea, grapes, berries and nuts are rich in polyphenols. Thanks to their phenolic chemical nature like VE, polyphenols serve as good antioxidants able to capture unstable free radicals (like Reactive Oxygen Species). However, not all phenolic compounds have the same scavenging capacity (i.e. free radical affinity) due to intrinsic differences in their chemical structure. Next to capturing radicals, some polyphenols can also work as effective recyclers of used up antioxidants like oxidised COST-EFFECTIVE VITAMIN E REPLACEMENT BY A PROVEN HIGHLY BIO-AVAILABLE NATURAL ANTIOXIDANT Steven Beckers Global Product Manager Antioxidants Impextraco - Belgium Figure 1. Structure of α-tocopherol with its phenolic hydroxyl group, allowing an easy transfer of hydrogen (H) atom (great reducing power).
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