Induction Of Maggot Antimicrobial Peptides And Treatment Effect Of Curing Salmonella Pullorum Infected Chicken

Antimicrobial peptides (AMPs) are important components of the host innate immune responses by exerting broad-spectrum antimicrobial activity against pathogenic microbes. The AMPs help housefly larva (maggot) live in the harsh environment filled with pathogenic bacteria. In this study, maggot AMPs was induced by inactivated Salmonella enterica and extracted crudely. The concentration and antimicrobial activity of maggot AMPs induced by Salmonella enterica (S. Enterica) was measured. In the animal experiment, chicken was artificially infected by S. Enterica. Then maggot AMPs extraction was used to cure infected chicken. The results showed that the expression level of AMPs was significant enhanced by induction, compared with control group (P<0.05). In addition, antibiotic activity of induced AMPs was significant stronger than non-induced AMPs, especially for S. Enterica. Minimal inhibition concentration (MIC) value of induced AMPs for S. Enterica was0.5mg/mL, which was lower than Staphylococcus (1.5mg/mL) and E. Coli (2mg/mL).For the animal experiment result, survival rate, blood indicators and intestinal bacterial changes showed that maggot AMPs and antibiotics had similar successful treatment effect. Animal experiments showed that:maggot antimicrobial peptides chicks diarrhea has a good therapeutic effect. The cure rate of no-induced AMPs group and induced AMPs group were28.33%and33.33%, there is no significant difference (p>0.05) between them, which were higher than the control group (16.67%)(p<0.05), lower than antibiotic group (48.33)(p<0.05). The number of intestinal bacteria in control group were relatively stable, maintaining at5×108CFU/g, while the umber of intestinal bacteria in treatment group showed a downward trend with significant difference, compared with control group., the number of bacteria in the induced AMPs group were significantly lower than the un-induced AMPs group, but higher than antibiotic group(p<0.05). The change of white blood cells and red blood cells were similar with the change of intestinal bacterial number.It is, therefore, indicated that maggot AMPs has potential for further development as a convenient antibiotic-alternative strategy to reduce the abuse of antibiotics and disease resistance.