Comprehensive evaluation of a pea co-product for piglet nutrition: fibre content, protein digestion, and intestinal barrier function

In pig production, weaning is a critical period associated with digestive intestinal disorders, due to the diet and environmental changes. The incorporation of transitional diets with high fibre and protein content represents a promising nutritional strategy to support piglets during the weaning period. This study examined the in vitro protein digestion and physicochemical properties of a co-product of interest for piglet at weaning: pea cream. The main objectives were i) to characterise pea cream in detail, focusing on its dietary fibre content, ii) to investigate in vitro the hydrolysis of its proteins, and iii) to examine the effect of pea cream digesta on intestinal barrier function using intestinal porcine epithelial cell lines (IPEC-J2). The composition in polysaccharides and the degradation of the pea cell wall were evaluated using biochemical and biophysical methods. The pea proteins from the pea cream were digested using an in vitro model of digestion simulating the upper gastrointestinal tract of pigs (based on the INFOGEST protocol). The obtained digesta were detoxified and then applied to IPEC-J2 cells. The results showed that pea cream was rich in dietary fibres, mainly insoluble, and contained approximately 4.6% protein (on an as fed-basis - 76.9% moisture). The in vitro protein digestibility of pea cream was high, with a significant release of proteins into the aqueous phase of the digesta earlier on during the digestion process. Microscopy revealed that some proteins remained encapsulated within cell wall fragments even after 6 h of digestion. The exposure of IPEC-J2 cells to detoxified pea cream digesta did not compromise the intestinal barrier integrity, as assessed by the passage of labelled molecules (FD4 and lucifer yellow) and the analysis of tight junction proteins (ZO-1 and occludin). In conclusion, pea cream presents several characteristics that make it a promising candidate for improving piglet weaning. It is a potential source of easily hydrolysable proteins, and its dietary fibres appear to maintain intestinal barrier function in the small intestine.