Bacterial enteritis is an important disease in poultry, causing loss of performance. It is a multifactorial disease with several predisposing factors. The use of feed additives in combination with proper management and prevention of coccidiosis allows you to grow your flock to its maximum genetic potential.
Gut health is crucial for performance, health and welfare of production animals. Next to common pathogen-induced intestinal pathologies, more subtle digestive disorders are an increasing problem. These are often characterised by intestinal inflammation and villus shortening, which affect performance. The main infectious causes that impair gut health in poultry are mainly from bacterial origin. Although necrotic enteritis (Clostridium perfringens) outbreaks are becoming rare under EU farming conditions, bacterial enteritis or dysbacteriosis is emerging since 2000. Preventive additives for gut health issues range from antimicrobial growth promoters and anticoccidials to alternative gut health additives.
Figure 1 – The vicious circle of bacterial enteritis and the use of feed additives to interact at the different stages of the vicious circle, adapted from De Gussem, 2010.
Genetic selection for growth has increased feed intake as a consequence. Modern broilers eat almost twice their own body weight every day. Anti-nutritional compounds such as non-starch polysaccharides (NSPs) and mycotoxins in the feed could lead to bad digestibility, resulting in more undigested protein in the lumen on which pathogenic bacteria can be fed. NSPs present in the feed increase viscosity in the gut, decreasing the passage rate of digesta. This leads to decreased absorption of digesta and increased incidence of wet litter. The presence of mycotoxins in the feed harm the intestinal barrier functioning and is one of the predisposing factors for secondary diseases and dysbacteriosis.
The gut microbiome exists of more than 1012 bacteria from which the host benefits in different ways: they expand the digestive capacity, they produce essential nutrients, increase colonisation resistance against pathogenic intruders and assist in detoxification. The more diverse and rich the microbiome, the healthier the host. The microbial community depends on the microbial substrate preference coming from the host diet, but also from bacterial metabolites. Cross feeding occurs between microbiota, e.g. butyrate and lactate producers.
The main functions of the gut are digestion and absorption of nutrients and the interface between organism and the outer world. The efficiency of feed digestion and absorption is directly proportional to the healthy surface of the intestine. The longer the villi, the greater the surface for absorption and healthier the microvilli, the more production of enzymes to break down the complex molecules. Moreover, the enterocyte lining is the physical barrier between intestinal lumen and blood, tightly sealed together by tight junctions, preventing bacteria and toxic substances to enter the blood and to cause inflammation and leaky gut. Together with the gut associated lymphoid tissue, the intestine is the largest immune organ mounting an adequate immune response to pathogens, but also preventing inflammatory response and keeping a state of oral tolerance against commensals and dietary compounds.
Figure 2 – A trial was conducted on 1080 male Cobb broilers, divided over 27 pens of 40 animals each, during 39 days. Each pen was randomly assigned to one of the 3 treatments: 1. Control, 2. N-Force at 1.5 kg/T in the starter, 1 kg/T in grower and 0.5 kg/T in finisher phase or 3. An antibiotic growth promoter Flavimpex.