Expression of chicken epidermal growth factor (cEGF) in Escherichia coli regulates the microflora structure of the duodenum to improve growth performance and intestinal morphogenesis in broilers

ABSTRACT

1. A study used gene synthesis to obtain the functional domains of chicken epidermal growth factor (cEGF) and examined their impact on broiler growth performance, small intestinal morphology, digestive enzyme activities in the intestinal contents and the structure of duodenal microflora.

2. The pET-32a-cEGF recombinant expression vector was constructed. The specific band at 26 KDa was shown by SDS-PAGE analysis and WB results. The purified protein content was shown to be 1687 μg/ml by assay.

3. A total of 180 healthy, one-day-old Arbor Acres male, white-feathered broilers were randomly divided into three dietary treatment groups (six replicate pens, 10 birds per replicate): A control diet (ND); cEGF diet (cEGF), control supplemented with 250 mg/kg cEGF and the control diet (CD) supplemented with 250 mg/kg chlortetracycline.

4. The results showed that feeding the cEGF and CD diet reduced FCR of broilers aged 1–21 d, average daily feed intake (ADFI) at 22–42 d, and the FCR in the whole period (1–42 d; p < 0.05). Compared with the ND group, the cEGF diet increased duodenal α-amylase and alkaline phosphatase activities in the 1–21 d, duodenal lipase, alkaline phosphatase, and ileal alkaline phosphatase activities in the post-period and increased villus height in the duodenum and ileum (p < 0.05). In addition, the ACE and Chao1 index for the birds fed cEGF were higher than the ND group (p < 0.05). At the phyla level, Firmicutes and Proteobacteria were dominant in all groups. At the genus level, the dominant genus was Lactobacillus. The LEfSe analysis showed that the cEGF group was enriched by 11 species including Brevibacillus, Eisenbergiella, Cloacibacterium, Butyricoccus spp.

5. The addition of 250 mg/kg cEGF to the diet can increase growth performance by improving intestinal development and digestive enzyme activity, which may be related to the duodenal intestinal microflora. Therefore, cEGF is an effective alternative to antibiotics in broiler farming.

KEYWORDS:

• cEGF
• growth
• duodenum microflora
• enzyme activity
• broiler
• small intestinal morphology

Author contributions

The authors CS, QL, JL and EL designed the experiments and reviewed the manuscript. Samples were collected at CS, QL, HY, JL, EL and CL. CS and QL conducted experiments. CS and CL analysed the data and completed the manuscript. CS, CL, GJ, YL and JT prepared images and edited the manuscript. All authors reviewed the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The datasets provided in this study can be found in the online repository. The name and login number of the repository are as follows: NCBI SRA Bioproject, login number: PRJNA1001146.

Additional information

Funding

This research work was supported by Liaoning Province ‘Xingliao Talents Plan’ project [Project NO. XLYC1803014].