Natural antioxidants from sea: a potential industrial perspective in aquafeed formulation

Aquaculture is set to grow amidst threats of new stressors and diseases. The increasing awareness on nutrition and feeding has led a paradigm shift towards therapeutic nutrition, an alternative aquaculture management strategy that can create a balance between productivity and long-term sustainability. The core objective behind this approach was to minimize the impact of stressors via neutralization of free radicals, repair of oxidative damage to biomolecules and membrane systems, immune augmentation and maintenance of normal physiological homoeostasis. The eventual shift of balance between oxidants and antioxidants leads to oxidative stress and subsequently immune suppression, pathological symptoms and slow growth. Therefore, in aquaculture the use of supplemental antioxidants and augmentation of endogenous cellular antioxidants becomes essential. Lipid rancidity is the major concern, which determines feed stability and storage time, besides the cellular antioxidant homoeostasis. As observed, ethoxyquin (EQ), the widely used synthetic antioxidant in animal feed industry, has growing human health hazard concerns. Efficient and cost-effective natural antioxidants are a real need of time. The most diverse marine ecosystem opens a new horizon for extraction and development of natural antioxidants from sea. The antioxidants such as vitamin E, vitamin C, peptides, amino acids, chitooligosaccharide derivatives (COS), astaxanthin, carotenoids, sulphated polysaccharides (SPs), phlorotannins, phenolic compound and flavones had shown a great potential to be used in feed formulation, as an additive for feed quality maintenance and shelf life. Therefore, new industrial perspectives and novel approaches are required for isolation and development of bioactive substances with antioxidative property for cost-effective feed.