Vitamins play a crucial nutritional and health-promoting role in the metabolism of livestock and poultry, making them essential feed additives in modern animal husbandry. They are used in large quantities, often imported, and tend to be expensive. Generally, factors affecting the stability and efficacy of single vitamin formulations are relatively few and well-studied. However, the widespread use of multi-vitamin premixes—homogeneous mixtures of multiple vitamin preparations with carriers or diluents—has made quality control more complex due to the varying physical, chemical, and biological properties of each vitamin. Effective quality control requires strict adherence to the following key points:
Formula Design
Overall, designing vitamin premix formulas is more complex than for trace element premixes or balancing energy, protein, and amino acids in animal diets. It is essential to accurately determine the vitamin needs of different livestock and poultry types and to set appropriate supplementation levels accordingly. In China, recommended vitamin needs are based on minimum levels to prevent deficiencies, as defined in both the national and NRC standards. Given processing and storage losses and other factors affecting vitamin potency, recommended dosages should include a safety margin above minimum requirements. However, excessive supplementation can be economically inefficient. Appropriate dosages should consider livestock health, production level, feed composition, environmental temperature, feeding practices, and processing techniques.
For economic efficiency in Chinese livestock production, moderate vitamin levels (about 10% above minimum) generally yield the best returns. Additionally, the unique physical and chemical characteristics of each vitamin must be taken into account to avoid compatibility issues. For instance, choline chloride has strong alkalinity and hygroscopic properties, which can significantly reduce the bioavailability of vitamins A, K3, and B6 and should be added separately. Vitamin C has strong reducing properties and is acidic in solution, causing vitamins B1, B2, B12, and folic acid to break down upon interaction. Furthermore, certain combinations, such as calcium pantothenate and niacin or organic acid preservatives and coccidiostats with vitamin B2, exhibit antagonistic effects. To increase the stability of multiple vitamins and other easily oxidized substances, antioxidants like ethoxyquin or BHT can be added to the premix; however, the total amount of oxidants in the final diet should not exceed safe limits (e.g., ethoxyquin below 150 mg per kg).
Ingredient Selection
There is a wide variety of vitamin preparations, differing significantly in quality, efficacy, formulation, and price. Selection should consider the intended use and production process, with priority given to high-potency, stable, and cost-effective products that meet feed-grade standards. Domestic products, though generally fresher and quality-assured, vary in stability, particularly with certain vitamins like A, D3, and E, which degrade faster in summer. Notable international vitamin manufacturers include Germany's BASF and Switzerland's Roche, with substantial imports to China; however, caution is required to avoid counterfeits and expired or near-expiration products.
For both domestic and imported vitamin raw materials, sample testing is essential. Regulatory authorities require premix producers to install UV monitoring equipment to verify the quality of most vitamin ingredients. Since vitamins are prone to degradation, they must be dosed according to their actual effective content. For example, vitamin A may come in concentrations of 500,000 IU/g or 200,000 IU/g, requiring careful distinction. Feed-grade products should be used as medical-grade vitamins are significantly more expensive.
To maintain potency, vitamin ingredients should be stored in a light-protected, sealed container immediately after opening, kept dry, and used promptly. Air conditioning should be used in storage and processing areas during summer, while dehumidifiers are recommended during the rainy season.