Prevent the proliferation of Clostridial enteritis

By Dr Stefaan de Smet and Dr Tom Verleyen, Kemin Agrifoods Europa, Herentals, Belgium

Growth retardation associated with impaired intestinal health around the third week of age is a major problem in broiler production, fully recognised by farmers, veterinarians and nutritionists. This problem occurs so frequently that it is no longer considered as a disease by some veterinarians. Nevertheless, it has been proven that the pathogen Clostridium perfringens is involved. It causes Clostridial enteritis and is prevalent in the broiler industry in all regions throughout the world. C. perfringens associated Necrotic Enteritis (NE) may appear with varying degrees of severity. An overview of the impact of Clostridium on broiler performance is summarised in Table 1. Birds acutely infected with C. perfringens will show high mortality rates of up to 30% of the flock. The clinical form of C. perfringens is easily seen and can be treated quickly through medication. Clinical signs include depression, ruffled feathers, diarrhoea and evident macroscopically lesions in the small intestines. A typical example of necropsies in the gastrointestinal tract due a Clostridium infection is shown in Photo 1. The clinical form of NE is easily detected, seldomly occurs, and can be treated.

A serious profit killer

In the subclinical form of the disease, damage to the intestinal mucosa caused by C. perfringens leads to decreased digestion and absorption of nutrients, reduced weight gain, and higher feed conversion. As subclinical NE is not always detected in the broiler flock there is a serious risk that it can pass unnoticed and affect production costs. The disease is known to be a serious profit killer, leading the FCR to increase 6–9 points and final body weight to reduce between 3-5%. Annual losses to producers in the US and Canada due to subclinical NE are estimated to be $5 cent per bird, according to a study reported in World Poultry (2000).

The same study showed that the subclinical form of NE is a worldwide problem with an average of 80% of the flocks having had Clostridium diagnosed (Figure 1). A follow-up study in 2005 indicated an increased incidence of Clostridial enteritis in all regions of the world, while recent European surveys confirmed the severity as well as the scale of the problem.

Typical signs of subclinical NE seen by poultry producers are specific growth retardation around 23 days of age (Figure 2). Litter quality diminishes as it becomes wet, leading to moisture levels above 40%. Undigested feed particles are often found in the litter (Photo 2). Consequences of poor litter quality are obvious, as it leads to increased issues of foot pad lesions, hock lesions, and breast blisters resulting in higher levels of rejections at the processing plant.

Preventing Clostridial proliferation

There are clear indications that Clostridial enteritis is under-diagnosed and treated too late. When watery intestinal content and wet litter are observed, Clostridium has already had the chance to proliferate. Preventive actions, through products such as CloSTAT™, with selected activity against C. perfringens before the first symptoms are observed, are a valuable solution to maintain a healthy gut flora. The heat stable product is safe and non-toxic to mammals, compatible with common antibiotics, coccidiostats and acid-based products used in the feed industry.

CloSTAT™ contains a unique strain of Bacillus subtilis PB6 that has been isolated and selected from the gut of healthy chickens that naturally coped with Clostridia challenge. Consequently it has a targeted effect against Clostridium. As a natural solution to maintain a balanced gastrointestinal tract, this bacillus isolate has demonstrated efficacy to raise poultry in a natural environment, reducing mortality and lesions score caused by NE.

Intestinal colonisation of beneficial bacteria is important to keep animals healthy. In poultry, beneficial gut bacteria include Lactobacillus spp., Bifidobacterium spp. These “good” bacteria help maintain the intestinal health by competing with “harmful” bacteria like C. perfringens for limited intestinal nutrients that are necessary for all. In numerous international animal trials, CloSTAT™ has proven to be an effective supplement for bird health. It suppresses Clostridium (Figure 3) and stimulates beneficial bacteria such as Lactobacillus spp. And Bifidobacterium spp to support the creation of a healthy balance.

Necrotic enteritis challenge trial

The most obvious way to check the anticlostridial effects of CloSTAT™ is through a NE challenge test, where the disease is artificially induced to the animals. A 27-day experiment was conducted to determine the effect of the product’s active microbial in an experimentally induced NE challenge test. All birds were infected on day 14 with a mixed coccidial inoculum and afterwards received an infection with C. perfringens to induce the disease. In the control group the infection caused mortality levels of 36%, confirming the challenge stress exposed to the birds (Figure 4). The addition of CloSTAT™ to the diet reduced mortality towards 9.4%, whereas Zn bacitracin (50 g/t) only lowered the mortality towards 17.2%. Supplementation of the bacillus isolate to the feed was also effective to restore animal performance parameters and compensate for the negative effects of the challenge. As subclinical NE is continuously present and will affect animal performance criteria, the beneficial effects of CloSTAT™ are directly seen under regular conditions in the field. Numerous broiler trials conducted over recent years have confirmed its efficacy to suppress subclinical NE, improve litter quality, and improve animal performance parameters (Figure 5). Since there are clear indications that Clostridial enteritis is under-diagnosed and treated too late. It is of utmost importance to take preventive action. Natural solutions can help maintain a balanced gastrointestinal tract and has demonstrated efficacy in reducing mortality and lesions score caused by NE.