Vitamin C (L-ascorbic acid) is one of the most essential yet challenging micronutrients in animal nutrition. Its potent antioxidant properties and role in immune function, growth performance, and stress resistance make it indispensable across poultry, swine, aquaculture, and livestock production. However, its well-documented instability during feed processing, storage, and gastrointestinal passage has driven decades of innovation in stabilization technologies.

This article provides procurement professionals and formulators with a comprehensive overview of vitamin C stability challenges, emerging delivery technologies, and application considerations across species — with a focus on the latest research developments in 2025-2026.

I. The Stability Challenge: Why Vitamin C Needs Protection

Vitamin C is inherently unstable. Its chemical structure — particularly the enediol group at the 2- and 3-carbon positions — makes it highly susceptible to degradation by heat, light, oxygen, moisture, and alkaline conditions.

Processing and Storage Losses Are Significant

In feed manufacturing, the losses can be substantial. Research shows that during feed processing:

• Vitamin C and Vitamin K3 losses can reach up to 40% during pelleting due to thermal degradation.
• High-temperature processing (>70°C) significantly reduces vitamin stability, with some heat-sensitive nutrients losing up to 90% of activity.
• In aquaculture, approximately 75% of supplemented vitamin C in shrimp feeds can be lost during processing at room temperature.

Application Environment Matters

The challenge is particularly acute in aquaculture. Studies have demonstrated that:

• After two hours in seawater at 20°C, conventional vitamin C experiences substantial leaching losses.
• Water-soluble nutrients like vitamin C are particularly vulnerable to leaching from feed particles in aquatic environments.

Industry Consensus: Protection Is Essential

These challenges have driven the animal nutrition industry to rely on stabilized vitamin C forms. According to the European Food Safety Authority (EFSA), which conducted a comprehensive assessment of vitamin C feed additives in October 2025, the authorized forms include ascorbic acid, sodium ascorbate, calcium ascorbate, ascorbyl palmitate, sodium calcium ascorbyl phosphate, and sodium ascorbyl phosphate.

The EFSA FEEDAP Panel concluded that these additives remain safe for target species, consumers, and the environment, with ascorbic acid and sodium ascorbyl phosphate confirmed as non-irritant to skin and eyes.

II. Emerging Innovation: The "New Vitamin C" – Tetraacetyl Vitamin C Ester (TVCE)

In April 2026, researchers from the Chinese Academy of Agricultural Sciences (CAAS) Feed Research Institute published a breakthrough study in the Journal of Animal Science and Biotechnology on a novel vitamin C derivative: Tetraacetyl Vitamin C Ester (TVCE).

A "Single Molecule, Two Nutrients" Approach

TVCE is designed to address two limitations simultaneously: vitamin C's instability and sodium acetate's hygroscopicity and short duration of action. By acetylating all oxidizable hydroxyl groups of vitamin C, researchers created a compound with:

• High lipophilicity (improved cell membrane penetration)
• Remarkable thermal stability (withstanding up to 160°C)
• Controlled release via enzymatic hydrolysis in the intestine

Key Findings from In Vivo Studies

Zebrafish trials: TVCE enhanced systemic antioxidant capacity (increased superoxide dismutase activity and total antioxidant capacity, decreased malondialdehyde levels) comparably or superiorly to traditional vitamin C-2-phosphate, even at lower vitamin C-equivalent dosages.

Tilapia trials: Dietary inclusion of 0.1% TVCE significantly improved weight gain rate and survival rate (P < 0.05) compared to a physical mixture of vitamin C-2-phosphate and sodium acetate — despite providing only 48% of the acetate equivalent.

Gut health benefits: TVCE supplementation improved intestinal morphology, reduced serum alanine aminotransferase and diamine oxidase levels, and optimized gut microbiota composition with increased Bacteroidota abundance.

Significance for Procurement and Formulation

TVCE represents a potential "upgrade and replacement" solution for vitamin C and organic acid supplementation in aquaculture feeds. Its successful synthesis through a simple, green, one-step acetylation reaction (yield >90%, purity >95%) suggests commercial viability.

III. Advanced Delivery Systems: Microencapsulation and Nanoencapsulation

Beyond chemical modification, encapsulation technologies are gaining traction as a strategy to enhance vitamin C stability and bioavailability.

Microencapsulation: Proven Results

Research has demonstrated that microencapsulated forms of vitamin C offer significantly better stability than conventional forms. Studies on feed premixes stored at 37°C and 12% moisture found that:

• Losses of microencapsulated vitamin C were significantly lower than those of conventional forms (P < 0.01)
• Under high-stress conditions, the difference between encapsulated and conventional forms was "very relevant"

The technology involves using micro-adhesion and microencapsulation techniques to "double reinforce" the VC molecule structure, protecting it from metal ions, light, moisture, heat, and compression during feed processing, storage, and transportation.

Nanoparticles: The Next Frontier

Chitosan-based nanoencapsulation represents a promising novel delivery system for vitamin C administration, particularly in aquaculture.

Key features of chitosan-cyclodextrin nanoparticles:

• Positively charged complexes (30–35 mV) in a nanosize range (< 300 nm)
• Encapsulation efficiency higher than 15%
• High stability — at least 90% of loaded vitamin C remains within nanoparticles after 2 hours in seawater

In vitro and in vivo results:

• Nanoparticles were able to penetrate fish intestinal epithelium in post-metamorphic sole larvae
• Rotifers fed with vitamin C-loaded nanoparticles increased their ascorbic acid levels up to 2-fold compared to control groups
• Total antioxidant capacity of nanoparticle-treated cells showed a statistically significant increase

IV. Application Considerations Across Species

Aquaculture

Aquaculture presents unique challenges due to water exposure and the inability of most fish species to synthesize vitamin C endogenously. Emerging technologies like nanoencapsulation and TVCE offer promising pathways to overcome traditional limitations. Research has shown that chitosan-based nanoparticles can penetrate fish intestinal epithelium and increase endogenous vitamin C content in rotifers used as live prey for fish larvae.

Poultry

In poultry nutrition, vitamin C plays multiple roles:

• Antioxidant protection: Reduces oxidative stress and protects against lipid peroxidation
• Immunity enhancement: Supports immune function and disease resistance
• Stress mitigation: Alleviates heat stress and other environmental stressors

Swine

For swine, vitamin C is essential for:

• Immune function: Particularly critical during weaning and disease challenge
• Stress resistance: Mitigates heat stress and transport stress effects
• Growth performance: Supports overall health and feed efficiency

Research has demonstrated that stabilized forms of vitamin C (such as microencapsulated products) can effectively address the instability issues that otherwise lead to deficiency during stress periods.

V. Implications for Procurement Professionals

What to Look for When Sourcing Vitamin C

1. Form Selection: Determine whether crystalline, phosphate-esterified, encapsulated, or novel forms (such as TVCE) best suit your application requirements and processing conditions
2. Stability Data: Request accelerated stability data at relevant processing conditions. EFSA's October 2025 assessment confirmed that authorized additives meet strict specifications with batch-to-batch variation within acceptable limits
3. Bioavailability Evidence: Look for in vivo studies demonstrating comparative performance
4. Regulatory Compliance: Verify compliance with applicable standards. EFSA's 2025 renewal authorization confirms the safety and efficacy of ascorbic acid and its derivatives for all animal species

The Importance of Third-Party Verification

Regular testing and third-party verification of vitamin C content in feed additives are critical to ensure product quality, regulatory compliance, and animal health. Under-dosing may lead to deficiencies, while over-dosing can result in economic losses or potential adverse effects.

Future-Proofing Your Supply Chain

Emerging technologies like TVCE and nanoencapsulation represent next-generation solutions that may offer superior performance compared to traditional stabilized forms. Procurement professionals should:

• Monitor commercial availability of these innovations
• Evaluate cost-benefit ratios for their specific applications
• Engage with suppliers who invest in R&D and offer technical support for new formulations

For technical specifications, batch data, or sample requests, please contact the Henan Liyin Biotech technical team.

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yolanda@liyinbio.com

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