Effect of Antimicrobial Peptide Microcin J25 on Growth Performance, Immune Regulation, and Intestinal Microbiota in Broiler Chickens Challenged with Escherichia coli and Salmonella

Abstract

The purpose of this study was to investigate the effects of antimicrobial peptide microcin J25 (MccJ25) on growth performance, immune regulation, and intestinal microbiota in broilers. A total of 3120 one-day-old male Arbor Acres (AA) broilers were randomly allocated to five groups (12 replicates, 52 chickens per replicate). The treatments were control, challenge (0 mg/kg MccJ25), different dosages of antimicrobial peptide (AMP) (0.5 and 1mg/kg MccJ25), and antibiotic groups (20 mg/kg colistin sulfate). The MccJ25 groups increased the body weight gain (starter and overall) that was reduced in the challenge group. The overall (day 1 to day 42) feed-to-gain ratio (G:F) was significantly decreased in AMP groups compared with the challenge group. Birds fed AMP had a decreased population of total anaerobic bacteria (day 21 and day 42) and E. coli (day 21 and day 42) in feces, as well as a lower Salmonella infection rate (day 21 and day 42) compared with birds in the challenge group. The villus height of the duodenum, jejunum, and ileum, as well as the villus height/crypt depth of the duodenum and jejunum were greater in AMP groups than birds in the challenge group. Moreover, MccJ25 linearly improved the villus height of the duodenum and jejunum. The addition of MccJ25 decreased the concentration of TNF-α, IL-1β, and IL-6 compared with challenge group. At d 21, MccJ25 linearly reduced the level of IL-6. In conclusion, dietary supplemented MccJ25 effectively improved performance, systematic inflammation, and improved fecal microbiota composition of the broilers.

Keywords: Antimicrobial Peptide; Escherichia coli; Microcin J25; Salmonella.

Figure 1

Effects of MccJ25 on Escherichia coli (E. Coli), lactic acid bacteria (LAB), Bifidobacterium counts (log 10 cfu/g), and total aerobic bacteria in the feces, as well as the Salmonella infection rate in broilers on days 21 and 42. Bars represent means ± SEM for 12 broilers per treatment. Within the same day, bars with different letters differ significantly (p < 0.05).

Figure 2

Effect of MccJ25 on intestinal mucosal morphology of duodenum, jejunum, and ileum in broilers. Scale bars, 100 μm.

Figure 3

Effects of MccJ25 on immunomodulatory factors concentration in the serum on day 21 and day 42. Bars represent means ± SEM for 12 broilers per treatment. Bars with different letters differ significantly (p < 0.05).