Necrotic enteritis is a major poultry disease leading to huge financial losses globally. The incidence and severity of this pathology have increased over the years. With the need to reduce antibiotic use, the market is asking for new solutions to alleviate the effect of necrotic enteritis while maintaining broiler performance.
Enteric diseases are a major concern for the poultry industry. They lead to production losses, higher mortality rates, reduced poultry welfare and an increased risk of contamination of poultry products for human consumption.
One of the most damaging diseases is necrotic enteritis, which is caused by the over-proliferation of Clostridium perfringens and usually occurs in broiler chickens at 3-4 weeks of age. Necropsy of infected birds reveals typical necrosis in the small intestines.
There are 2 forms of necrotic enteritis. Firstly there is the acute form, which is characterised by a sudden increase in mortality. In most cases, there are no clinical warning signs and it can lead to mortality rates of up to 50%. Clinical signs of diseased animals include depression, dehydration, ruffled feathers, inappetence and diarrhoea.
Conversely, the second form, which is sub-clinical necrotic enteritis often goes undetected and thus untreated by producers. This form of pathology represents 80% of cases and is the most costly for the industry. Difficult to diagnose, it can lead to significant production losses, decreased feed efficiency and negatively impact welfare.
Necrotic enteritis is typically managed with antibiotics, some in rotation programme systems. However, the use of antibiotics is being reduced in many regions of the world due to the emergence of antimicrobial resistance. Consumer acceptance of products from antibiotic-fed animals is also decreasing.
To meet the challenge of maintaining broiler performance and limiting necrotic enteritis impact without antibiotic use, producers are increasingly interested in alternative strategies, like feed additives.
Phytogenic molecules, such as eugenol and garlic compounds, have been identified as having interesting properties. Eugenol is a naturally occurring molecule in cloves that has demonstrated its ability to reinforce the gut physical barrier by increasing the thickness of the intestinal mucus layer and decreasing bacterial attachment in the intestinal epithelium.
Several poultry studies have also shown that garlic compounds support immunity parameters by limiting inflammatory processes and promoting optimal gut digestive functions, thereby reducing the number of available nutrients for Clostridium perfringens to grow.
In a recent trial performed in Virginia in the US, a blend of eugenol and garlic compounds was compared to Bacitracin Methylene Disalicylate (BMD) and was shown to promote broiler performance when under necrotic enteritis challenge conditions.
This 42-day trial was performed on 1,000 Cobb500 broilers split into 4 groups:
At 12 days of age, all birds except the negative control groups were inoculated via oral gavage by titrated Clostridium perfringens culture to mimic a sub-clinical necrotic enteritis challenge.