Substrate-Dependent Enzymatic Depolymerization of Palmaria palmata Xylan and Wheat-Bran Arabinoxylan

Seaweed Palmaria palmata has gained attention recently as a potential feed ingredient for livestock due to its high nitrogen content and higher digestibility. However, P. palmata has a high fiber content, which can be difficult to digest by monogastric animals. The aim of this experiment was to determine the optimal dose of xylanase for maximum release of potential prebiotics (xylooligosaccharides (XOS)) from the fiber matrix of P. palmata. Five xylanase dosages were tested: no xylanase (NX), the manufacturer-recommended dosage (1X), and two times (2X), three times (3X), or four times (4X) the manufacturer-recommended dosage in a simulated in vitro digestion experiment. Samples were analyzed for fiber as non-starch polysaccharides (NSP), and the oligosaccharide profiles were determined by high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). P. palmata contained high levels of total NSP (44.0%), primarily as soluble xylan, while wheat bran contained mainly insoluble arabinoxylan. Increasing xylanase dose beyond 1X increased XOS release, with the highest concentration observed at 3X (p < 0.001). In conclusion, xylanase improved degradation and promoted generation of potentially prebiotic XOS from P. palmata, highlighting its potential as a functional ingredient in pig diets.