In Vitro Evaluation of Brown Seaweed <i>Laminaria</i> spp. as a Source of Antibacterial and Prebiotic Extracts That Could Modulate the Gastrointestinal Microbiota of Weaned Pigs

Abstract

Laminaria spp. and their extracts have preventative potential as dietary supplements during weaning in pigs. The first objective of this study was to evaluate increasing concentrations of four whole seaweed biomass samples from two different Laminaria species harvested in two different months in a weaned pig faecal batch fermentation assay. Particularly, February and November whole seaweed biomass samples of L. hyperborea (LHWB-F and LHWB-N) and L. digitata (LDWB-F and LDWB-N) were used. In the next part of the study, the increasing concentrations of four extracts produced from L. hyperborea (LHE1–4) and L. digitata (LDE1–4) were evaluated in individual pure-culture growth assays using a panel of beneficial and pathogenic bacterial strains (second objective). The LHE1–4 and LDE1–4 were obtained using different combinations of temperature, incubation time and volume of solvent within a hydrothermal-assisted extraction methodology (E1–4). In the batch fermentation assay, the L. hyperborea biomass samples, LHWB-F and LHWB-N, lowered Bifidobacterium spp. counts compared to the L. digitata biomass samples, LDWB-F and LDWB-N (p Enterobacteriaceae counts (p Salmonella Typhimurium and Enterotoxigenic Escherichia coli with LDE1 having a similar effect on both of these pathogenic strains, albeit to a lesser extent (p B. thermophilum counts (p p Bifidobacterium thermophilum and Lactiplantibacillus plantarum counts (p Laminaria spp. were identified in vitro with the potential to alleviate gastrointestinal dysbiosis in newly weaned pigs.

Keywords

• brown macroalgae
• bifidogenic
• antibacterial
• seaweed polysaccharides
• weaned pig
• gastrointestinal microbiota