Construction of strain engineered for expression of porcine β-defensin-2/cecropin P1 fusion antimicrobial peptides and its growth-promoting effect and antimicrobial activity.

Objective: To generate recombinant () engineered for expression of porcine β-defensin-2 (pBD-2) and cecropin P1 (CP1) fusion antimicrobial peptide and investigate their anti-bacterial activity and their growth-promoting and disease resisting activity .

Methods: The pBD-2 and CP1 fused gene was synthesized using the main codons of and inserted into plasmid pMK4 vector to construct their expression vector. The fusion peptide-expressing was constructed by transformation with the vector. The expressed fusion peptide was detected with Western blot. The antimicrobial activity of the expressed fusion peptide and the recovered pBD-2 and CP1 by enterokinase digestion was analyzed by the bacterial growth-inhibitory activity assay. To analyze the engineered on growth promotion and disease resistance, the weaned piglets were fed with basic diet supplemented with the recombinant B. subtilis. Then the piglets were challenged by enteropathogenic (). The weight gain and diarrhea incidence of piglets were measured after challenge.

Results: The recombinant engineered for expression of pBD-2/CP1 fusion peptide was successfully constructed using the main codons of the . Both expressed pBD-2/CP1 fusion peptide and their individual peptides recovered from parental fusion peptide by enterokinase digestion possessed the antimicrobial activities to a variety of the bacteria, including gram-negative bacteria (, , and ) and gram-positive bacteria (). Supplementing the engineered to the pig feed could significantly promote the piglet growth and reduced diarrhea incidence of the piglets.

Conclusion: The generated strain can efficiently express pBD-2/CP1 fusion antimicrobial peptide, the recovered pBD-2 and CP1 peptides possess potent antimicrobial activities to a variety of bacterial species . Supplementation of the engineered in pig feed obviously promote piglet growth and resistance to the colibacillosis.