Antibacterial peptides are a class of peptides produced by the biological defense system against foreign pathogens. They have anti-bacterial, fungal, and
Mold, virus, protozoa, cancer cells and other activities, and not easy to produce drug resistance, has broad application prospects (An Chunju et al, 2003). Since the approval of antibiotics as a feed additive, the problems of drug residues and drug resistance that have emerged have not been fundamentally resolved. The EU has completely banned the use of growth-promoting antibiotics for feed since January 2006. The cecropin antibacterial peptide was first discovered by the Swedish scientist Boman (Boman HG et al., 1995), which was found in 1980 after the use of C. vaginalis and Escherichia coli to induce the sirloin, and it was found that it not only has a broad-spectrum antibacterial effect, but also It has a certain killing effect on viruses, fungi, tumors, etc. Cecropin antibacterial peptide is also one of the most thoroughly studied and most effective antibacterial peptides.
The company has been researched by experts and scholars to produce cecropin antibacterial peptides, which are artificially designed and synthesized and successfully expressed in Bacillus subtilis (Xiang Chen et al., 2010). In vitro tests have proven to be effective in inhibiting harmful bacteria such as Escherichia coli, Staphylococcus aureus, and Salmonella. Moreover, the cecropin antibacterial peptide preparation has no toxic and side effects, no harmful residue in the livestock and poultry body, conforms to the development direction of green environmentally friendly food, and meets the needs of domestic and foreign markets, and is an ideal way to develop green feed additives. Therefore, it is an excellent choice for antibiotic replacement. At present, cecropin antibacterial peptide has achieved successful fermentation of fermenter. Therefore, it can be directly applied to the diet of weaned piglets to explore the effect of cecropin antibacterial peptide on the growth performance of weaned piglets, which will promote its production in animal production. Applications.
1 Materials and methods
1.1 Test Animals A total of 240 healthy weaned piglets of Duoc × Landrace × Yorkshire with an initial body weight of 11.64 ± 2.30 kg were used for the test.
1.2 Test Design The weaned pigs selected according to the principle of similar body weight and similar genetic basis were completely randomly divided into 4 treatments, 6 replicates per treatment, and 10 pigs per revolution (circle) (test and female). The experimental design was : control group, ie antibiotic group (basic diet + 200 mg / kg 10% sulfuric acid antibiotics + 1000 mg / kg 10% bacitracin zinc); test group (basic diet + 250 mg / kg of silkworm Antibacterial peptide); test group 2 (basic diet + 500 mg / kg cecropin antimicrobial peptide); test three groups (basic diet + 750 mg / kg cecropin antimicrobial peptide). The trial period is 28 days, managed and recorded by a dedicated person, and other daily management is carried out as normal.
1.3 Test diet The corn-soybean-based basal diet was used to prepare porcine experimental basal diets and premixes in accordance with NRC (1998) porcine nutritional requirements. The basic diet formula and nutritional level of the test are shown in Table 1. The formulation of 4% premix of the diet of each test group is shown in Table 2. The cecropin antibacterial peptide was provided by Beijing Zhongnong Yingtai Biotechnology Co., Ltd.
Table 1 Basic diet formula and nutritional level
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