Pullorum disease, which is one the most serious intestinal diseases in poultry production, is generally treated by adding antibiotics to the feed of infected chickens. Although antibiotics are generally quite effective against the disease, they can harm small intestinal flora and mucosa. The objective of this experiment was to determine if antimicrobial peptides (AMPs) from housefly (Musca domestica) larvae can be used to treat pullorum disease. The study included AMPs extracted from Salmonella enteric serovar Pullorum-infected larvae as well as non-infected ones (referred to as induced-AMPs and non-induced AMPs, respectively). Tests were then conducted determine (i) the activity of these AMPs against S. pullorum and (ii) the effects of the AMPs on intestinal Lactobacillus acidophilus and mucosa epithelial cells in S. pullorum-infected chicks. The results showed that S. pullorum-induced AMPs and non-induced AMPs both exhibited antimicrobial activity against S. pullorum. Small intestinal L. acidophilus populations in convalescent chicks that had been treated with induced AMPs showed similar patterns to those in healthy chicks. Induced AMPs also had relatively little effect on the number of mast cells, lymphocyte cells, and goblet cells in the small intestine of convalescent chicks compared with healthy chicks. In contrast, treatment with antibiotics generally reduced the number of all three cell types, especially in the duodenum. In conclusion, AMPs from housefly larvae offer potential for effective treatment of S. pullorum-infected chickens without the harmful side effects of antibiotics.
