Development of Microencapsulation Technology for Targeted Delivery of Enzymes in The Gastrointestinal Tract of Ruminants

In ruminant nutrition, enzymes such as beta-glucosidase (BG) hold potential for enhancing fibre digestion post-rumen in the hindgut of ruminants. Enhancing fibre digestion in the hindgut is crucial for improving feed utilisation efficiency and increasing energy availability from fibrous feed sources. However, protecting enzymes from rumen degradation remains a major challenge. To address this challenge, this study investigated the use of alginate-based microencapsulation as a protective delivery strategy designed to protect BG during ruminal and gastric transit and enable their targeted release in the hindgut. A range of formulations incorporating chitosan, sucrose, maltodextrin, pectin, and shellac were produced using a Buchi Encapsulator B-390 and assessed for encapsulation efficiency (EE), structural integrity, and resistance to degradation. Initial trials with alginate alone yielded low EE (3 ± 1.0%) due to leakage and syneresis, whereas the addition of 0.1% chitosan to the gelling solution increased EE to 49 ± 2.64% by reducing bead porosity. Incorporating enzyme stabilizers such as sucrose (4%) and maltodextrin (2%) further improved EE significantly to near 100± 2.16%. However, in vitro rumen fermentation showed a dry matter degradation of 42–54%, underscoring the need for more robust microcapsules. To improve ruminal stability, a Design of Experiments (DoE) approach identified shellac and chitosan as key ingredients that influence the structural integrity of the beads. The optimized formulation (1.5% alginate, 0.25-16% shellac, 4% sucrose, external 0.5-2% chitosan coating) reduced dry matter disappearance (DMD) from 51.3% in uncoated beads to as low as 0%. The final formulation (1.5% alginate, 4% shellac, 4% sucrose, external 2% chitosan coating) achieved 88% EE and maintained structural integrity after simulated ruminal and abomasal incubation, followed by visible matrix disintegration in the intestinal phase. Although direct measurement of enzyme release was hindered by spectrophotometric interference from shellac-dye binding and feed particle interactions, surrogate indicators including swelling behaviour, dry matter disappearance, calcium ion release, and sucrose retention confirmed that the beads protect entrapped actives in the rumen and gastric phases and undergo targeted disintegration and release of their cargo in the intestine. The use of this approach would potentially enable the protected delivery of feed digesting enzymes to the hindgut of ruminants to enable enhanced fibre degradation and improved feed utilisation efficiency. The novelty of this study lies in the integration of hydrophobic (shellac) and polyelectrolyte (chitosan) modifiers into alginate-sucrose matrices to create a novel rumen-bypass encapsulation system. Beyond BG, this formulation offers promise for the post ruminal delivery of probiotics, vitamins, and other bioactives. Future in vivo studies are recommended to validate these findings under the complex conditions of the ruminant gastrointestinal tract.