This review provides a comprehensive overview of seaweed use in animal feed, tracing how perceptions have shifted from a low-value ingredient to a functional additive. Early studies suggested seaweeds had limited nutritional value, largely due to their low energy content and reduced performance at high inclusion rates. However, more recent research highlights that their real value lies in bioactive compounds rather than traditional nutrients.
Seaweeds - particularly Ascophyllum nodosum - contain complex polysaccharides, antioxidants, and phenolic compounds that deliver prebiotic and immune-supporting effects. At low inclusion levels, these compounds can improve gut health, enhance nutrient digestibility, reduce pathogen load, and support overall animal performance, with a prebiotic potential at least five times that of inulin, a well-known commercial prebiotic.
The authors conclude that seaweeds are best used as functional feed additives rather than bulk ingredients. Their benefits depend heavily on inclusion rate and processing, with small amounts delivering measurable improvements in health, productivity, and food safety outcomes.
Evans and Critchley