European Journal of Nutrition & Food Safety

The increasing demand for sustainable, functional, and health-promoting ingredients in pet nutrition has stimulated growing interest in marine macroalgae (seaweeds) as alternative feed resources for dogs and cats. India, with a coastline exceeding 7,500 km, harbours rich seaweed biodiversity and represents an abundant yet underutilised source of nutritionally valuable biomass. Seaweeds contain diverse bioactive compounds, including polysaccharides such as laminarin, fucoidan, alginate, and agar-derived oligosaccharides, as well as proteins, essential minerals, vitamins, polyphenols, carotenoids, and polyunsaturated fatty acids. These components have been associated with improvements in gastrointestinal health, immune function, antioxidant capacity, and overall physiological well-being. Seaweed-derived polysaccharides exhibit prebiotic properties by promoting beneficial gut microbiota and enhancing the production of short-chain fatty acids, while antioxidant compounds help mitigate oxidative stress and maintain cellular homeostasis. In addition, various seaweed bioactives demonstrate immunomodulatory and anti-inflammatory activities that may enhance disease resistance and support healthy ageing. Reported benefits also include improved nutrient utilisation, favourable modulation of blood biochemical parameters, enhanced skin and coat condition, better oral health, and increased feed palatability. However, certain seaweed species may accumulate excessive iodine, heavy metals, or other naturally occurring antinutritional factors, necessitating appropriate species selection, processing methods, quality control measures, and optimised dietary inclusion levels. Despite these promising attributes, evidence from companion animal studies remains limited, with much of the current knowledge derived from livestock and laboratory animal models. Overall, this review highlights the considerable potential of seaweeds as sustainable functional ingredients in dog and cat nutrition. Strategic utilisation of India's abundant seaweed resources could support the development of innovative pet foods while contributing to environmental sustainability and the blue economy. Further species-specific research is required to establish standardised products, optimal inclusion rates, long-term safety, and efficacy in companion animals.