Diarrhea is a serious issue in raising livestock, especially in weaned piglets. Overusing of antibiotics leads to a severe environment pollution. Therefore, our objective was to determine whether engineered antimicrobial peptide KR-32，a 32-residue peptide，display high antimicrobial activity with minimal hemolytic activity and cytotoxicity. Results of Minimum inhibitory concentration (MIC), transmission electron microscopy (TEM), indicated that antimicrobial peptide KR-32 exerts antimicrobial activity by destroying cell membrane integrity. Piglets with clinical diarrhea were divided into three groups (8 piglets each group) and treated with saline (control), KR-32 or Ciprofloxacin Lactate for 3 days.The diarrheal index was scored according to a fecal consistency scoring system (0, normal; 1, soft feces; 2, mild diarrhea; and 3, severe diarrhea) as previously described (
Bhandari et al., 2008;
Yi et al., 2016). The diarrheal index showed that all piglets were diarrhea. Comparisons were made by one-way ANOVA or Student's t-test with SPSS 16.0 software (SPSS Inc., Chicago, IL, USA). Effects were considered significant at P < 0.05. We found that the treatments of both AMP KR-32 and Ciprofloxacin Lactate were effectively attenuated diarrheal rate (P < 0.05) and diarrhea index（P<0.05） compared with the control group.Pro-inflammatory cytokines such as IL-6 and TNF-α were the important indicators for intestinal inflammation during weaning. It has been demonstrated that low levels of IL-6 and TNF-α are beneficial for controlling diarrhea of piglets (
Yi et al., 2017). Here, we found that KR-32 treatment significantly reduced levels of the IL-6 (P<0.05)and TNF-α(P<0.05) in serum indicating KR-32 regulates inflammation and diarrhea. In conclusion, we defined a novel role of antimicrobial peptide KR-32 in regulating infectious disease and gut health in livestock.
Keywords: antimicrobial peptide, Diarrhea, weaned piglets, antibacterial activity,
Reference
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