Necrotic enteritis is widely common and economically significant. It is caused by the proliferation of the Clostridium perfringens bacterium, associated and triggered by protozoans of the Eimeria genus, which preliminarily causes coccidiosis (Figure 1). This disease is present around the world, and the animal production market spends millions of dollars a year to fight it. Modern tools in the fields of molecular biology and immunology have been used to shed light on these pathogens and their harms, in an attempt to create more effective means to control coccidiosis and, consequently, necrotic enteritis.
The harms caused by coccidiosis and necrotic enteritis are known, and recent research shows that the metabolism of amino acids and energy also undergoes several intermediate changes, which reinforces the importance of controlling the disease.
In addition to modulating different physiological processes, including protective immune responses, nutrition, metabolism and pathogen elimination, the intestinal microbiota of animals can change the physiopathology of parasitic diseases, offering resistance or promoting enteric parasitic infections. Bacteria naturally found in the gut act as molecular adjuvants, providing indirect immunostimulation, helping the body protect itself from parasitic infections.
A recent study conducted by Huang et al. (2018) reported that Eimeria infection significantly increases the number of pathogenic bacteria and reduces the amount of Lactobacillus and Ruminococcus, which are considered beneficial.
Considering that broiler undergoes a fast breeding cycle, attention to the risk of infections must be intensified, and preventive actions have become indispensable, as coccidiosis can occur at any time and, if not properly controlled, can cause great production loss.
Today, the market offers different prevention methods like (attenuated and virulent) vaccines, and anticoccidial agents added to feed, with (synthetic and glycoside ionophores) or without (mono and divalent ionophores) antibacterial activity. However, the use of ionophore anticoccidial agents in animal production has been questioned, and it has already been restricted in some markets. Therefore, strict management, health, and nutritional plan are needed, combined with alternative compounds added to the diet to improve the intestinal integrity and immune response modulation, which will help animals respond to Eimeria proliferation more effectively.
ImmunoWall® is one of the solutions that can be helpful in pathogen control programs. This natural compound helps in reducing contamination and in preventing the problem. Therefore, ImmunoWall® has superior performance compared to other products because it is made of a thick Saccharomyces cerevisiae cell wall, with high concentrations of β-Glucans and MOS, resulting in an additive that ensures best results and great cost-effectiveness (Figure 2). MOS can trap pathogenic bacteria, like E. coli and Salmonella, preventing their colonization and proliferation in the gut. β-Glucans stimulate the production and activity of macrophages, defense cells that play an important role in the immune system and that can phagocytize and destroy microorganisms. Thus, supplementation with ImmunoWall® ensures broilers keep their intestinal microbiota balanced and improve their immune responses, resulting in decreased contamination and translocation of pathogenic bacteria to other organs in the body.
Figure 2. ImmunoWall® modes of action
A study (unpublished data) was conducted in Southern Poultry Research (Athens, GA, USA) by Charles L. Hofacre, MS, DVM, MAM, PhD, in 2013, with one-day chicks (start of diet treatments) contaminated with 5,000 oocysts of Eimeria maxima at 14 days and with 1x108 CFU of Clostridium perfringens per broiler at 19, 20 and 21 days old. No coccidiostat was used in the feed, and no vaccine against coccidiosis was administered. Results showed reduced intestinal lesion scores and mortality in the groups that received ImmunoWall® (0.5 kg/MT up to day 28 of the study). The group of challenged broilers not treated with any additive or AGP had 44% mortality and a 0.575 lesion score. Broilers treated with Virginiamycin (20 g/MT) had a 68% reduction in mortality and a 35% reduction in the lesion score compared to the control group. The group given ImmunoWall® had a 75% reduction in mortality and a 15% reduction in the lesion score (Table 1).
Table 1. Necrotic enteritis score and mortality of broiler chickens challenged with Eimeria maxima and Clostridium perfringens.
Necrotic enteritis (NE) score at 21 days (score based on a 0-3 scale, with 0 indicating normality and 3 indicating the most severe). Mortality was checked when broilers were 28 days old. 1AGP: Broilers infected, 20 gMT of Virginiamycin. 2IMW: Broilers infected, 0.5 kg/MT of ImmunoWall®. Except for Treatment 1, all broilers were challenged with ~5,000 oocysts of Eimeria maxima at 14 days and with 1x108 CFU per broiler of Clostridium perfringens at 19, 20 and 21 days. A study conducted at Southern Poultry Research, Athens, GA, USA
Another study recently conducted by Beirão et al. (2018) analyzed the effect of ImmunoWall® on the intestinal integrity of broilers. At two days old, broilers were orally challenged with Salmonella Enteritidis at 108 CFU per broiler and were fed with ImmunoWall® supplemented diets (0.5 kg/MT). Results show that at four days (two days after infection), ImmunoWall® reduced the marker passage to the blood in the challenged group, indicating that it had improved intestinal integrity.
Chart 2. Intestinal permeability of broilers challenged with Salmonella Enteritidis at 4 days old.
Treatments: Control+SE: Control, challenged; IMW: No challenge, treated with 0.5 kg/MT of ImmunoWall®; Control: Control, no challenge; IMW+SE: challenged, treated with 0.5 kg/MT of ImmunoWall®. Intestinal integrity (permeability) assessment. Higher values indicate higher permeability, which then indicates poorer mucosa integrity. Statistical relevance is indicated by different letters on each group. The differences indicated were calculated with one-way ANOVA, with Tukey’s range test (P < 0.05).
The intestinal microbiota is important for intestinal homeostasis and host responses to enteric pathogens. Understanding how bacteria respond to infection may broaden our knowledge regarding infectious diseases. A microbiome analysis was conducted in a study, and the results showed that supplementation with ImmunoWall® changed the microbiota population. At 14 and 21 days old, remarkable genera were found in broiler chickens, including Ruminococccus torques and Lactobacillus. Ruminococccus torques has mucolytic function and are associated with better productivity in broilers (TOROK et al., 2011). Lactobacillus, among other functions, produces short-chain fatty acids and bacteriocins that prevent pathogen growth. As mentioned earlier, Eimeria infection reduces the amount of both of these genera, which reinforces the use of ImmunoWall® as a preventive and beneficial solution to control coccidiosis.
Therefore, the more effective the coccidiosis control plan, the better the enteric quality, microbiota balance, and immune response. ImmunoWall® is a natural additive and a feasible solution to improve intestinal health and food safety at low dosages, providing excellent cost-effectiveness.