Intestinal delivery of micro-encapsulated zinc oxide to manage postweaning diarrhea in piglets

The post-weaning period marks a two-week window that is a vulnerable time for piglets. During this period, they are at an increased risk for illness – particularly diarrhea, which can lead to a failure to thrive, and in the most severe cases, death. The cause of diarrhea is often due to Escherichia coli intestinal infection and interventions typically includes antibiotic use. However, because of the push to be less antibiotic-dependent, non-drug alternatives have gained more favour. One of these options include zinc oxide (ZnO), an inorganic compound found to have antibacterial properties. Its integrative use in the animal industry has already suggested its efficacy in managing post-weaning diarrhea. However, it has been subject to overuse which has lead to major downstream polluting effects and animal toxicity. Therefore, research advances are in effort to reduce the amount of ZnO delivered to piglets while maintaining a potent effect against E. coli. This research evaluates the encapsulation of ZnO within natural alginate and whey protein or a commercially purchased polymer, Eudragit L100, in order to achieve this goal. The purpose of the encapsulating ingredients is for the targeted delivery of ZnO to the infected intestinal location, allowing ZnO to act with specificity and in a concentrated dose. It was found that through in vitro studies using porcine digestive fluids, encapsulation of ZnO within Eudragit L100 was capable of delivering 70% of the total encapsulated ZnO to the intestinal region, while only 50% was delivered when ZnO was encapsulated in alginate and whey protein. The ability of the encapsulation materials to protect against premature release of ZnO during gastric transit can account for the difference in these results. Therefore, ZnO encapsulation within Eudragit L100 demonstrates greater prospect for a complete delivery of ZnO to the intestinal region with minimal loss. The broader implications of this suggest a possible solution to reduce the overuse of ZnO, while preserving its effective interventional use in the animal industry.

Key words: post-weaning diarrhea, zinc oxide, encapsulation.

Published in the proceedings of the Animal Nutrition Conference of Canada 2020. For information on the event, past and future editions, check out https://animalnutritionconference.ca/.