Lipid matrix microencapsulation for effective delivery of essential oils and organic acids to improve gut health in weaned piglets
Essential oils (EO) are considered as one of the most promising antibiotic alternatives in the swine industry due to their gut health-promoting effects. However, EO are very volatile, evaporate quickly during feed processing and storage, and are rapidly absorbed in the upper gastrointestinal tract in pigs. Micro-encapsulation (e.g., lipid matrix micro-encapsulation) has been popularly used to deliver bioactive compounds (e.g., EO and vitamins) to the animal’s gut. However, there is a lack of information on the stability of EO during feed processing and storage, and the intestinal release of EO from the lipid matrix microparticles in weaned piglets. More studies are still needed to comprehensively understand the mechanisms behind the protection of micro-encapsulated EO against pathogens in weaned piglets. Therefore, the purposes of the thesis were to 1) evaluate the stability of thymol microencapsulated in combination with organic acids (OA) in commercially available lipid matrix microparticles during feed pelleting process and storage; 2) determine the intestinal release of thymol from the lipid matrix microparticles with in vitro and in vivo approaches; and 3) investigate the effects microencapsulated OA and EO on growth performance, immune system, gut barrier function, nutrient absorption, and microbiota in weaned piglets challenged with enterotoxigenic Escherichia coli (ETEC) F4. The lipid matrix microparticles were able to maintain the stability of thymol during a feed pelleting process and storage (12 weeks) and allow a slow and progressive intestinal release of thymol in the weaned piglets. Moreover, the supplementation of micro-encapsulated OA and EO alleviated diarrhea and inflammation response, and improved gut barrier integrity, intestinal morphology, enzyme activities, and nutrient transport in the weaned piglets experimentally infected with ETEC F4. In conclusion, micro-encapsulated OA and EO can improve gut health in weaned piglets with physiological challenges and can be used as an alternative to antibiotics for swine production.
Essential oils, Micro-encapsulation, Pigs, Organic acids, Escherichia coli