PEA PROTEIN-BASED CAPSULES FOR DELIVERY OF PROBIOTICS IN ANIMAL FEED

Abstract

Probiotics have been used as a prophylactic antibiotic alternative to improve health and growth performance in animals. However, the selection of probiotic strains is limited due to the lack of stability during storage, processing and passage through the upper gastrointestinal tract. In the current study, pea protein isolate-alginate based capsules (PPC) were made by extrusion and their efficacy to improve probiotic viability during storage, feed processing and delivery to the distal intestine were investigated. Encapsulation protected against loss of Bifidobacterium adolescentis viability during freeze-drying compared to non-encapsulated bacteria. Capsules also improved the viability of freeze-dried B. adolescentis during long-term (335 d) storage at -80 °C. In contrast, encapsulation did not improve viability of B. adolescentis or Lactobacillus reuteri when stored above 0 ºC. Loss of viability during short duration (up to 180 s) heat challenge (up to 90 °C) was reduced by encapsulation. Encapsulation also protected against loss of viability during heat challenge up to 90 °C with a pressure of 95 MPa for 30 s, however, encapsulation did not protect bacteria added to feed and subject to commercial pelleting. A naturally selected antibiotic resistant L. reuteri, was selected to facilitate strain-specific tracking of viable bacteria in the gastrointestinal tract. Supplementation of pigs with encapsulated antibiotic resistant L. reuteri in feed did not increase bacterial counts in upper tract compared with non-encapsulated bacteria, however, the counts of viable antibiotic resistant L. reuteri in the distal gastrointestinal tract and feces of pigs was increased. In conclusion, pea protein isolate-alginate based encapsulation improved bacteria viability during freeze-drying and provided limited benefit during cold storage of sensitive bacteria. Improved resistance to environmental challenge (heat and pressure) was observed, but was insufficient to protect against conditions found during commercial feed pelleting. Encapsulation may improve the shelf life of probiotic bacteria during cold storage and this work is the first work to show improved delivery of bacteria to the distal digestive tract of the pig. However, post-pellet application technologies and improved methods of viability protection during storage above 0 ºC are required to broaden the commercial application of probiotics in the feed industry.