Abstract: To further explore the impact of antimicrobial peptides on broiler performance, we conducted a comparative study between a group receiving 150 mg/kg of antimicrobial peptides and another group supplemented with neomycin sulfate. The results demonstrated that broilers in the antimicrobial peptide group exhibited slightly superior performance compared to those in the antibiotic group. Specifically, their average daily gain increased by 5.49%, while feed conversion efficiency improved by 5.47%. Additionally, mortality rates decreased by 39.84%, and elimination rates dropped by 33.76%. This study was supported by the China Feed Industry Information Network, which focuses on feed solutions and animal husbandry services.
Keywords: antibacterial peptide; broiler; production performance
With the growing global demand for green, pollution-free poultry products, the limitations of antibiotics have become increasingly evident. The European Union banned the use of antibiotic growth promoters in animal feed starting in January 2006. As a result, the development of antibiotic alternatives has become essential.
The main component of antibacterial peptides is cecropin, a cationic peptide first discovered by Swedish scientists in 1980. It is part of the innate immune system and exhibits broad-spectrum antibacterial activity, including effectiveness against fungi, viruses, and protozoa. Its unique mechanism of action makes it less prone to resistance and enhances overall immunity. Our company has successfully synthesized and expressed cecropin antibacterial peptides in Bacillus subtilis. These peptides exhibit unique antibacterial properties and nutritional benefits, effectively inhibiting harmful bacteria like Escherichia coli, Staphylococcus aureus, and Salmonella in vitro. Furthermore, they are non-toxic, leave no harmful residues in animals, and align with the trend toward green, eco-friendly food production, meeting both domestic and international market demands.
This experiment aimed to investigate the effect of adding cecropin antibacterial peptides to broiler diets on their performance. We carefully designed the study to include appropriate amounts of antibacterial peptides.
Materials and Methods:
1.1 Test Animals and Design
The study involved 2346 healthy Rose 308 broiler chickens, which were evenly divided into two groups based on body weight, with 1172 chickens per group. The control group received neomycin sulfate, while the experimental group was given cecropin antibacterial peptides. The details of the test design are outlined in Table 1.
Table 1: Experimental Design
| Group | Treatment | Addition Amount (mg/kg) |
|-------|-----------|------------------------|
| Antibiotic Group | Neomycin Sulfate | 250 (0-21 days), 250 (22-41 days), 300 (42-47 days) |
| Antibacterial Peptide Group | Cecropin Antibacterial Peptide | 150 (0-21 days), 150 (22-41 days), 150 (42-47 days) |
1.2 Feeding Management
The trial took place at the broiler breeding base of Hebei Health Feed Co., Ltd. The chickens were raised on the ground with free access to feed and water. Lighting was set at 24 hours/day for the first three days and reduced to 23 hours/day from day four onwards. The house temperature was maintained at 35°C for the first two days, gradually decreasing to 30°C in the second week and stabilizing at 23°C in the third week to ensure healthy growth.
Immunizations followed the company's standard protocol, with twice-daily disinfections three days before and after chick arrival.
1.3 Test Diet
Diets were formulated according to the Chinese broiler feeding standards outlined in the Chicken Feeding Standards (2004). The basic diet composition and nutritional levels are detailed in Table 2. Antimicrobial peptides were sourced from the National Feed Engineering Technology Research Center, while other ingredients came from Health Feed Company.
Table 2: Basic Diet Composition and Nutritional Levels (%)
| Ingredient Composition | 0-21 Days Old | 22-41 Days Old | 42-47 Days Old |
|------------------------|---------------|----------------|----------------|
| Corn | 61.70 | 63.50 | 67.45 |
| Cardamom | 20.50 | 19.00 | 16.00 |
| Cottonseed Meal (43%) | 2.50 | 2.50 | 4.00 |
| Peanut Meal | 1.50 | 2.00 | 0 |
| Secondary Powder | 4.00 | 5.00 | 5.00 |
| Domestic Fishmeal | 2.00 | 1.50 | 0 |
| Stone Powder | 1.30 | 1.20 | 1.20 |
| Calcium Hydrogen Phosphate | 0.80 | 0.70 | 0.60 |
| Oil | 1.00 | 1.40 | 2.50 |
| Salt | 0.15 | 0.15 | 0.02 |
| DDGS | 3.50 | 2.00 | 2.00 |
| Choline | 0.05 | 0.05 | 0.05 |
| Premix | 1.00 | 1.00 | 1.00 |
| Total | 100.00 | 100.00 | 100.00 |
Nutritional Levels:
| Metabolic Energy (Mcal/kg) | 2.90 | 3.00 | 3.10 |
| Crude Protein (%) | 18.18| 17.33| 15.22|
| Lysine (%) | 0.89 | 0.84 | 0.71 |
| Methionine (%) | 0.30 | 0.28 | 0.25 |
| Calcium (%) | 0.84 | 0.75 | 0.63 |
| Available Phosphorus (%) | 0.34 | 0.30 | 0.23 |
*Premix provides per kilogram of full price: Vitamin A, 14400 IU; Vitamin D, 1800 IU; Vitamin E, 20 mg; Vitamin K, 1.5 mg; Vitamin B1, 2.25 mg; Vitamin B2, 9 mg; Calcium Pantothenate, 15 mg; Niacin, 30 mg; Vitamin B6, 3 mg; Vitamin B12, 0.025 mg; Folic Acid, 0.75 mg; Choline, 1000 mg; Manganese, 60 mg; Zinc, 40 mg; Iron, 80 mg; Copper, 8 mg; Iodine, 0.35 mg; Selenium, 0.15 mg.
This comprehensive approach ensures that the study accurately evaluates the potential of cecropin antibacterial peptides as a sustainable alternative to traditional antibiotics in broiler farming.
Circular Machine Needle,Circular Knitting Machine,Circular Knitting Machine Needles,Knitting Machine Needles
Changzhou Longfu Knitting Co., Ltd. , http://www.circularmachine.com