Validation of Micro-Encapsulation Method to Protect Probiotics and Feed Enzyme from Rumen Degradation

We hypothesize that supplementation of live yeast or feed enzyme (FE) may improve intestinal digestion and gut health, but with ruminants, the challenge is to deliver additive with high activity post-ruminally due to the highly proteolytic environment of the rumen. The objective of this study was to develop a micro-encapsulation method by measuring ruminal stability of encapsulated yeast and FE, and its release in the intestine. Live yeast and liquid FE were encapsulated using barley protein hordein and glutelin as capsule material. The barley protein powders were hydrated at pH 11.0 to form a 15% (w/v) solution. The pH was then adjusted to 7.0 followed by an immediate mixing with yeast or FE to form a coarse emulsion using a homogenizer. Microcapsules were then formed by passing the premixed emulsion through a microfluidizer system. The mixtures were spray-dried using a laboratory scale spray dryer. The ratio of capsule to additive was 1:1. The stability of encapsulated products in the rumen was measured as DM disappearance (DMD) in batch culture. Briefly, the encapsulated products (100 mg) were weighed into Ankom bags and placed in 100-mL serum bottles. Rumen inoculant (15 mL) from beef heifer and buffer solution (45 mL) was added to each bottle and incubated at 39^oC for 0, 3, 6, 12 or 24 h. The residues in bags were digested in 1% pancreatin solution for 1 h to remove the encapsulation protection. Number of yeast colonies (cfu/g) was enumerated by spread plate method. Enzyme activity (EC 3.2.1.1) was assayed and expressed as μmol glucose equivalents/min/g FE. The DMD of encapsulated yeast were 3.1, 7.8, 9.1, 12.0 or 16.0%, and the cfu were 9.5, 2.2, 1.3, 1.1 and 0.6 (× 10⁹), respectively, for residues after 0, 3, 6, 12, and 24 h of incubation. The DMD of encapsulated FE were 5.1, 31.4, 33.8, 40.6 or 43.6%, and the enzyme activity in residue were 41.9, 33.8, 19.7, 12.7 and 10.2 µmol/min/g, respectively, at 0, 3, 6, 12 and 24 h of incubation. The results showed that the encapsulated yeast products were stable in the rumen. Subsequently, the encapsulated yeast was released by digesting in pancreatin solution and cfu counts demonstrated over 90% survival rates. It suggests that this encapsulation technique is applicable as a novel method for delivering active yeast to the intestine. However, this technique may be not efficacy to protect liquid enzyme from rumen degradation.