Intercurrent coccidiosis and necrotic enteritis of chickens: rational, integrated disease management by maintenance of gut integrity

Abstract

Coccidiosis and necrotic enteritis (NE) are globally common, sometimes intercurrent, diseases of poultry. The risk of NE, due to the Gram-positive bacterium Clostridium perfringens, has increased in recent years because of the voluntary or legally required withdrawal of the use of certain in-feed antibiotic growth promoters with anticlostridial activity. In-feed ionophorous anticoccidial drugs incidentally also possess anticlostridial activity. Such ionophores, although not banned, are usually precluded when live anticoccidial vaccines are used, potentially increasing yet further the risk of NE. This review provides information for the design of rational, integrated management strategies for the prevention and control of coccidiosis and NE in chickens by maintaining gut integrity. Because of differences in local availability of feed ingredients and national legislations regarding antibiotic growth promoters and anticoccidial vaccine licensing, no universal strategy is applicable. The diseases and their interactions are described under the headings of forms of disease, diagnosis, sources of infection, pathophysiological effects, predisposing factors, and control methods. Elements of gut integrity, which influences host predisposition and clinical responses to disease, include physical development, immune competence, gut enzyme activity, mucin production, gut flora and epithelial damage. Experimental studies of coccidiosis and NE are compared, and where possible reconciled, with field observations. Gaps in knowledge and necessary further experiments are identified. Insights are provided regarding interactions between coccidiosis, NE, and the use of live anticoccidial vaccines. Recent changes in NE prevalence in commercial flocks, and their possible causes, are discussed. The necessarily wide range of topics reviewed emphasizes the enormous complexity of this disease combination, and indicates the importance of a multidisciplinary approach in order to reduce its harmful impact on the world's poultry industry.

Efficacy of early treatment with toltrazuril in prevention of coccidiosis and necrotic enteritis in chickens

“…a varying mortality rate occurs (Williams, 1996). It has been shown to increase the risk of NE occurrence (Al-Sheikhly & Al-Saieg, 1980) by damage of epithelia (Williams, 2005), protein leakage and increase of mucus secretion allowing C. perfringens to replicate and produce toxins (Van Immerseel et al, 2004, 2009Collier et al, 2008;Cooper & Songer, 2010). NE was effectively prevented by mixing antimicrobial growth promoters in the broiler feed (Elwinger et al, 1998;Lanckriet et al, 2010).…”

“…However, due to the emergence of bacterial resistance, the use of antibiotics is and will be further diminished. Various methods for NE prophylaxis have been investigated; for example, treatment with ionophorous anticoccidial drugs (Williams, 2005) or a so far experimental approach of vaccination with a C. perfringens toxoid vaccine (Mot et al, 2013). The effect of anticoccidials in a subclinical NE model was tested by Lanckriet et al (2010) and narasin, maduramicine and salinomycine showed a certain efficacy.…”

“…Accordingly, netB-negative strains did not induce NE in experimental infection models (Keyburn et al, 2008(Keyburn et al, , 2010. Chicken coccidiosis is the predisposing disease that is most commonly associated with NE and therefore co-infection models involving coccidia and clostridia may be employed to induce NE lesions (Williams et al, 2003;Williams, 2005).…”

Natural plant extracts and prebiotic compounds as alternatives to antibiotics in broiler chicken diets in a necrotic enteritis challenge model

“…Necrotic enteritis (NE) is an acute or chronic enterotoxaemia caused by Clostridium perfringens (van der Sluis 2003;Williams 2005). C. perfringens is a Gram-positive, obligate anaerobic, spore-forming bacterium readily found in soil, dust, used poultry litter and as a normal inhabitant of the gut microflora of healthy birds (Dahiya et al 2006).…”

HSV (Herpes Simplex Virus)

“…Since the ban of using antibiotics as growth-promoters in the animal feed, the concept of digestive flora and the management of bacterial balance of digestive tract have become more important. Digestive disorders have increased in parallel to this withdrawal (Van Immersel et al, 2004) and are often sources of under performances due to healthy problem as necrotic enteritis or coccidiosis (Williams, 2005).…”