Immunization of broiler chickens with recombinant alpha-toxin protein for protection against necrotic enteritis

Abstract

Necrotic enteritis ( NE ), caused by Clostridium perfringens ( CP ), has been reported in a wide variety of avian species including chickens. Necrotic enteritis has been reported in most parts of the world with acute outbreaks occurring sporadically and most often in broiler chickens after maternal immunity declines with bird age. This study was conducted to develop computer-aided design of a recombinant CP protein vaccine in an experimental model of necrotic enteritis. A synthetic rCPA which has been designed using predictive tools expressed and obtained through cloning, used to immunize and assess intestinal lesion scores, antibody levels, growth performance, and CP reduction in vivo. Broilers were immunized on days 7, 14, and 21 (V groups) with the purified recombinant clostridium alpha-toxin. On days 24, 25, and 26, the birds were orally challenged with CP (1.0 × 10 9 CFU/bird). Increased body weight (BW), clearance of CP, increased antibodies, and intestinal lesion scores were measured as protection parameters after oral co-infection with CP. Birds immunized and challenged with recombinant protein (CHV) experienced significantly less body weight loss and less intestinal lesions compared to the positive control group (PC). Higher anti-recombinant anti-rCPA antibody titers were observed in the challenged vaccinated (CHV) and only vaccinated (V) groups with an increased level CP clearance of intestinal contents in immunized birds. Based on these results, vaccination with computer-aided clostridial recombinant proteins, particularly rCPA toxin, enhances protective immunity against experimental necrotic enteritis in broiler chickens.