Restrictions on antibiotics are driving the search for alternative feed additives to promote gastrointestinal health and development in broiler chicken production. Proteins including antimicrobial peptides can potentially be applied as alternatives to antibiotics and are one of the most promising alternatives. We investigated whether the addition of MPX to the diet affects the production performance, immune function and the intestinal flora of the caecal contents of broiler chickens. One hundred one-day-old chickens were randomly divided into two groups: control (basal diet) and MPX (20 mg/kg) added to the basal diet. The results indicated that dietary supplementation with MPX improved the performance and immune organ index, decreased the feed conversion ratio, increased the villus length, maintained the normal intestinal morphology and reduced the IL-6 and LITNF mRNA expression levels of inflammation-related genes. In addition, MPX increased the mRNA expression of the digestive enzymes FABP2 and SLC2A5/GLUT5 and the tight junction proteins ZO-1, Claudin-1, Occludin, JAM-2 and MUC2, maintained the intestinal permeability and regulated the intestinal morphology. Moreover, MPX increased the CAT, HMOX1 and SOD1 mRNA expression levels of the antioxidant genes. Furthermore, a 16S rRNA microflora analysis indicated that the abundance of Lactobacillus and Lactococcus in the cecum was increased after addition of MPX at 14 d and 28 d. This study explored the feasibility of using antimicrobial peptides as novel feed additives for broiler chickens and provides a theoretical basis for their application in livestock.
Keywords: antimicrobial peptide mastoparan X; broiler chickens; immunity; intestinal health; performance.