Grapes are rich in phenolic compounds with many health-promoting properties for animals
and humans. Grape seed extract, grape skin extract and their mixture belong to the
registered feed additives in the EU. The aim is to give a brief overview of the most
important findings from in vitro and in vivo studies and to emphasise the beneficial
impact of grape phenols on intestinal health in pigs.
A total of 13 (2013-2023) studies were included in the analysis. In addition to the
antioxidant, wound healing and anti-inflammatory properties, supplementation with
GSP (Grape seed extract) also significantly reduced the incidence of diarrhoea in
piglets. Studies in pigs showed that grape phenols have modulatory properties on the
gut microflora by increasing the levels of beneficial bacteria and exhibiting antimicrobial
activity against various pathogenic bacteria. They improve the morphology of the small
intestinal mucosa, promote the growth of the small intestinal villi, and show promising
properties regarding intestinal integrity and reduction of permeability, due to expression
of genes encoding epidermal growth factor receptor, insulin-like growth factor 1 (IGF-1)
and IGF-1 receptor in the duodenum, as well as an increased expression of TJ proteins.
GSE has been also found to have dose-dependent positive and negative effects on the
gut, although it is generally considered safe.
In conclusion supplementation with grape extracts showed potential for intestinal
health in pigs and is recommended for further investigation in relation to specific
intestinal disorders and under various challenging factors.
