DEVELOPMENT OF AN IN VITRO ASSAY TO EVALUATE ANTIMICROBIALS

Abstract

In vitro assays were developed using small intestinal contents from broilers fed maltodextrin in preparation for shipping. This was done to establish an effective bactericidal dose of allicin or lysozyme as ingredients in maltodextrin-based feed. The antimicrobials were added to overnight cultures of gut material bacteria from maltodextrin fed broilers and a pure culture of Salmonella. Following this, lysozyme was incorporated into maltodextrin feed at 0, 10 and 20 g.kg-1 of feed and offered for 9 h to 4 pens of 20 birds per treatment. Bacterial numbers were analyzed using Proc Mixed of SAS. Allicin and lysozyme inhibited Enterobacteriaceae and Clostridium perfringens, respectively, in vitro. Lysozyme showed the most promise; it reduced bacterial numbers in nutrient broth. Feeding lysozyme-enriched maltodextrin for 9 h inhibited bacilli growth (P<0.05) when evaluated using next generation sequencing. Lysozyme was effective in reducing specific bacterial numbers in the gut of market-aged broilers