Oxidized β-Carotene Is a Novel Phytochemical Immune Modulator That Supports Animal Health and Performance for Antibiotic-Free Production

Abstract

Oxidized β-carotene (OxBC), a phytochemical that occurs naturally in plants, is formed by the spontaneous reaction of β-carotene with ambient oxygen. Synthetic OxBC, obtained by full oxidation of β-carotene with air, shows considerable promise as an in-feed antimicrobial alternative additive that enhances health and performance in livestock. OxBC is predominantly composed of β-carotene-oxygen copolymers that have beneficial immune-modulating effects that occur within the innate immune system by priming it to face microbial challenges and by mitigating the inflammatory response. OxBC does not have any direct anti-bacterial activity. Further, unlike traditional immune stimulants, OxBC modulates but does not stimulate and utilize the animal's energy stores unless directly stress-challenged. These immune effects occur by mechanisms distinct from the provitamin A or antioxidant pathways commonly proposed as explanations for β-carotene's actions. Trials in poultry, swine, and dairy cows with low parts-per-million in-feed OxBC supplementation have shown performance benefits over and above those of feeds containing regular vitamin and mineral premixes. Through its ability to enhance immune function, health, and performance, OxBC has demonstrated utility not only as a viable alternative to in-feed antimicrobials but also in its ability to provide tangible health and performance benefits in applications where antimicrobial usage is precluded.

Keywords: antibiotic alternative; growth and health performance; metaphylaxis; oxidized β-carotene; sustainability.

Figure 1

Formation of OxBC by spontaneous oxidation of β-carotene produces mainly a β-carotene oxygen copolymer compound and minor amounts of many apocarotenoid breakdown products.

Figure 2

Geronic acid is an apocarotenoid product characteristic of OxBC that is used as a proxy marker compound for estimating OxBC.

Figure 3

Formation of geronic acid as β-carotene is oxidized in dried, powdered carrot exposed to air. Measurements at time 0 used freshly dehydrated carrot purée. The dried purée was immediately ground to powder, spread thinly on a tray, and exposed to air and ambient light. Values at subsequent time points were determined using the powder.