Effects of Muco-defen® on Clostridium perfringens-induced necrotic enteritis in broilers

Necrotic enteritis (NE) prevalently occurs in broilers aged from two to six weeks that mainly caused by Clostridium perfringens C. perfringens can rapidly proliferate and produce toxins in intestine that contribute to losses in productivity, raising mortality, and contamination products. A variety of approaches were explored to prevent the incidence of NE in poultry. Among these, probiotics shows promise as an alternative to antibiotics in inhibiting growth of gastrointestinal pathogens.

Muco-defen® (Life Rainbow Biotech Co., Ltd. Taiwan) is the product composed of selected Bacillus strains via patent solid-state fermentation process to ensure the 2nd metabolites production, and formulated with essential oil, that can prevent colonization of pathogens by competition exclusion and a specified 2nd metabolites were identified and proof showing the bactericidal activity on intestinal pathogens. The purpose of this feeding experiment was conducted to evaluate the effects of C. perfringens -challenged broilers with probiotics diet on growth performance, intestinal morphology, and changes in cytokines of immunity.

The study was a 35-d trial with broilers housed in cages, with 3 replicates per treatment, and 4 chicks per cage. A total of 48 one-day-old male broilers (Avian) were randomly assigned into four groups, including (1) basal diet (control) plus oral administration of Clostridium perfringens (1 × 10⁸CFU/ml), (2) basal diet plus oral administration of Clostridium perfringens (1 × 10⁸CFU/ml) and 2 g/kg of bacitracin methylene disalicylate (BMD, 2kg/ton), (3) basal diet plus oral administration of Clostridium perfringens (1 × 10⁸CFU/ml) and Muco-defen® (3kg/ton). The birds were orally challenged with Clostridium perfringens (1 × 10⁸ CFU/ml) on 18, 19 and 20 d of age.

The individual body weight, average daily gain, average daily feed intake and feed conversion ratio (FCR) were recorded every week. Broilers were sacrificed on 22d and 35 d of age. The small intestine from birds was examined for degree of Clostridium perfringens-induced necrotic lesions, villus length and crypt depth. Pro-inflammatory mRNA expression levels in the spleen and Bursa of Fabricius of broilers under Clostridium perfringens challenge were determined.

After feeding with the diets for 5 weeks, no significant difference was found in the growth performance according to body weight and food intake among the groups. Compared with the control group, Muco-defen®-diet caused a trend in improving FCR in broiler chickens between d1 and d21 (Figure 1).

As shown in figure 3, histological examination showed remarkable differences in Muco-defen®-diet group compared to control group. The ratios of villus height to crypt depth were compared, significant higher ratios were observed in the jejunum of chickens fed with BMD and Muco-defen®-diet (Figure 4). These findings indicate that Muco-defen® could improve morphology and inhibit the –induced necrotic lesions in the small intestines of broilers.

The mRNA expression of IFN-γ and IL-1β in bursa was significantly up-regulated by C. perfringens challenge after feeding with antibiotics or Muco-defen® on d22 and d35 compared to the control group (Figure 5). The result demonstrated that Muco-defen® feeding would alter levels of transcripts encoding proinflammatory cytokines.

This study was conducted to investigate the effects of Muco-defen® on broiler growth performance, intestinal villus and crypt morphometry, and immunomodulation of cytokines. The results demonstrated that dietary supplementation of Muco-defen® improved the morphology of small intestine and alleviated the intestinal necrotic lesions of C. perfringens-challenged birds. Cytokines are immunoregulatory peptides that participate in innate and adaptive immunity responses. Muco-defen® affect the mRNA expression of IFN-γ and IL-1β that can be expected to trigger the cellular immunity responses in broiler challenged by C. perfringens. Thus, Muco-defen® may be an alteration to intensify protective immunity against enteric pathogens in poultry.