Ameliorative Effects of Anti-Clostridial Egg Yolk Antibodies (IgYs) in Experimentally-Induced Avian Necrotic Enteritis

SIMPLE SUMMARY: Necrotic enteritis (NE) is an important enteric infection in poultry. Since the ban on the use of antimicrobials growth promoters, NE has re-emerged significantly in commercial poultry. The current study aimed to evaluate the ameliorative effects of anti-clostridial egg yolk antibodies (EYAs) in NE. Passively immunized birds showed improved behavioral signs and gross and microscopic lesions. Although EYAs showed ameliorative potential in our study, studies regarding safe production and reliable application remain overdue. ABSTRACT: The present study was planned to evaluate the ameliorative effects of egg yolk antibodies (EYAs) in broiler chicken. For this purpose, 80-day-old broiler chickens were divided into four groups (A–D), where group A was kept as negative control. Experimental infection with C. perfringens (1 × 10(8) cfu/mL) was induced via oral route on days 17, 18 and 19 of the experiment in groups B, C and D. Groups C and D were passively immunized by anti-clostridial IgYs @ 1 mL per bird via oral and oral and intramuscular (I/M) routes respectively, on days 21 to 24, and on days 22 and 24 of the experiment, respectively. Two necropsies were performed (the first on day 26th and the second on day 35th). Birds in group B showed behavioral signs e.g., laziness, depression and diarrhea, gross post-mortem lesions e.g., increase in the relative weights (RW), due to acute swelling and congestion of liver and kidneys and ballooning and hemorrhages of jejunum and microscopic lesions e.g., congestion and necrosis in liver and kidneys’ parenchyma and disrupted epithelium with fewer goblet cells in jejunum, compared to the group A. Birds in groups C and D, showed significant improvements in clinical and behavioral signs, RW of liver, kidneys and jejunum, swelling, congestion and mononuclear cells’ infiltration in liver and kidneys and damages in the jejunal-wall, compared to group B. The most significant changes were found in birds of group C. Our study revealed ameliorative effects of EYAs on certain biological parameters however, further studies would be needed to justify a safer production and a reliable application of EYAs in NE outbreaks.