Calcium Montmorillonite-Based Dietary Supplement Attenuates Necrotic Enteritis Induced by Eimeria maxima and Clostridium perfringens in Broilers

Abstract

Necrotic enteritis (NE) is a poultry disease caused by Clostridium perfringens and characterized by severe intestinal necrosis. The incidence of avian NE has been progressively increasing following the removal of antibiotics from poultry feed. We evaluated the effect of diets supplemented with the thermally-processed clays, calcium montmorillonite (CaMM) on clinical signs, immunopathology, and cytokine responses in broiler chickens using an experimental model of NE consisting of co-infection with Eimeria maxima and C. perfringens. In Trial 1, Ross/Ross chickens were fed from hatch with a normal basal diet or a CaMM-supplemented diet with or without a fermentable fiber, an organic acid, and/or a plant extract, and co-infected with E. maxima and C. perfringens under conditions simulating clinical infection in the field. Chickens fed a diet supplemented with CaMM plus a fermentable fiber and an organic acid had increased body weight gain, reduced gut lesions, and increased serum antibody levels to C. perfringens α-toxin and NetB toxin compared with chickens fed the basal diet alone. Levels of transcripts for interleukin-1β (IL-1β), IL-6, inducible nitric oxide synthase, and tumor necrosis factor-α superfamily-15 were significantly altered in the intestine and spleen of CaMM-supplemented chickens compared with unsupplemented controls (p<0.05). In Trial 2, Cobb/Cobb chickens were fed an unsupplemented diet or a diet supplemented with CaMM or Varium^®, each with a fermentable fiber and an organic acid, and co-infected with E. maxima and C. perfringens under subclinical infection conditions. Compared with unsupplemented controls, broilers fed with CaMM plus a fermentable fiber and an organic acid had increased body weight gain, and reduced feed conversion ratio, mortality, and intestinal lesions, compared with chickens fed an unsupplemented diet (p<0.05). Dietary supplementation of broiler chickens with CaMM plus a fermentable fiber and an organic acid might be useful to control avian NE in the field.

Keywords: Clostridium perfringens; Eimeria maxima; calcium montmorillonite; coccidiosis; necrotic enteritis; organic acid.

Fig. 1.

Schematic illustration of the experimental protocol. Ab, antibody; CP, C. perfringens; DCPI, days following C. perfringens infection; EM, E. maxima.

Fig. 2.

Levels of transcripts for proinflammatory cytokines and iNOS in intestinal jejunum IELs. Intestinal IELs were collected at day 2 following C. perfringens infection and the levels of transcripts for IL-1β, IL-6, iNOS, and TNFSF15 were measured by quantitative RT-PCR. Individual transcript levels were normalized to GAPDH transcript levels. Each bar represents the mean normalized transcript level±SEM (n=5). Bars with different superscripts are statistically different according to the Duncan's multiple range test (p<0.05).

Fig. 3.

Levels of transcripts for proinflammatory cytokines and iNOS in spleen cells. Spleen cells were collected at day 2 following C. perfringens infection and the levels of transcripts for IL-1β, IL-6, iNOS, and TNFSF15 were measured by quantitative RT-PCR. Individual transcript levels were normalized to GAPDH transcript levels. Each bar represents the mean normalized transcript level±SEM (n=5). Bars with different superscripts are statistically different according to the Duncan's multiple range test (p<0.05).