An updated review on alternative strategies to antibiotics against necrotic enteritis in commercial broiler chickens

The significant surge in poultry production observed in recent years has compelled scientists to devise strategies for more secure and cost-effective output. However, due to complete or gradual restrictions on the use of antimicrobial growth promoters (AGPs), enteric diseases that were formerly contained with success have now resurfaced, posing difficulties for the global poultry industry. Necrotic enteritis (NE) is a highly significant enteric bacterial disease that causes significant economic losses (2–6 billion annually) to the poultry industry worldwide. The disease is caused by an anaerobic spore-forming bacterium, Clostridium perfringens type A, C and G strains. Several factors predispose the disease, including coccidiosis, poor management and biosecurity. Necrotic enteritis is distributed worldwide in both clinical and subclinical forms. The clinical form causes ruffled feathers, diarrhoea, weight loss, pseudomembrane formation, Turkish towel-like appearance of the intestinal mucosa, foul-smelling gases, and high mortality. The subclinical form has less noticeable symptoms, such as poor nutrient digestion and absorption, poor FCR and cholangiohepatitis. Poultry researchers are continuously seeking for novel and viable antibiotic alternatives to prevent and control this important disease. Several non-antibiotic alternatives, including prebiotics, probiotics, synbiotics, postbiotics, organic acids, enzymes, phytogenic substances, bacteriophages, egg yolk antibodies, and vaccines have been utilised, with varying degrees of success and limitations. Choosing the most optimal alternative method to combat NE is challenging due to the variable influence on disease control and potential effects on cost-efficiency. However, an integrated approach that takes into account the utilisation of suitable alternatives to antibiotics, the composition of the diet and effective husbandry practices may yield highly promising outcomes. The current review provides comprehensive details of the concept, effects and mechanisms associated with the application of different non-antibiotic alternatives that have been employed for the management of NE in broilers.