In young pigs, the challenge of weaning frequently leads to dysbiosis. This predisposes pigs to intestinal infection such as post-weaning diarrhoea (PWD). Dietary interventions to reduce PWD have centred on dietary inclusion of antibiotic growth promoters (AGP) and antimicrobials in pig diets, or high concentrations of zinc oxide. These interventions are under scrutiny because of their role in promoting multidrug resistant bacteria and the accumulation of minerals in the environment. There are significant efforts being made to identify natural alternatives. Marine polysaccharides, such as laminarin and fucoidan from macroalgae and chitosan and chito-oligosaccharides from chitin, are an interesting group of marine dietary supplements, due to their prebiotic, antibacterial, anti-oxidant, and immunomodulatory activities. However, natural variability exists in the quantity, structure, and bioactivity of these polysaccharides between different macroalgae species and harvest seasons, while the wide range of available extraction methodologies and conditions results in further variation. This review will discuss the development of the gastrointestinal tract in the pig during the post-weaning period and how feeding marine polysaccharides in both the maternal and the post-weaned pig diet, can be used to alleviate the negative effects associated with weaning.
Keywords: dietary supplement; marine polysaccharides; pig; weaning.