A natural feed additive that yields performance results comparable to AGP use? It really does exist. Varium® supports a healthy intestinal tract AND can help provide production economics similar to antibiotic-fed birds.
Necrotic enteritis is a common infectious disease that costs the poultry industry billions of dollars each year. With more and more poultry production systems moving toward the global objective of reduced in-feed use of antibiotics for growth promotion, maintaining a healthy intestinal environment now relies more heavily on other management methods to reduce the risk of necrotic enteritis development. Keep reading to learn more about the origins of necrotic enteritis, the relationship between necrotic enteritis and coccidiosis, and management of the disease risk in ABF production systems.
C. perfringens: The Cause of Necrotic Enteritis
Necrotic enteritis is caused by Clostridium perfringens types A and C: gram-positive, spore-forming anerobic bacteria. C. perfringens can be found throughout the poultry house environment and has spores which, under the right environmental conditions, can survive for long periods outside the bird. The normal microbiota of the bird contains C. perfringens, so its presence alone doesn’t necessarily indicate an issue. Instead, disease occurs when predisposing conditions in the bird cause overgrowth of the pathogen. There are multiple factors that can contribute to C. perfringens overgrowth including diet changes, immune status and stress, intestinal pathophysiology and concurrent infection with coccidiosis.
Multiple exotoxins can be produced by C. perfringens, including alpha-toxin and necrotic enteritis toxin B-like toxin (NetB). Alpha-toxin is cytotoxic to endothelial cells, red blood cells, white blood cells and platelets, whereas NetB toxin forms pores in cell membranes that allows electrolytes to rupture cells, causing cell death and necrotic lesions in the small intestinal mucosa. These two toxins are known to have a role in necrotic enteritis development.
Impaired Nutrient Adsorption
In healthy birds, the epithelium and mucus layer of the intestine form a selective barrier between internal tissues and the external environment (the intestinal lumen). The natural barrier allows nutrients through the intestinal wall but not pathogens and their biotoxins. When there is an overgrowth of C. perfringens, there is a breakdown of the defensive barrier. The damage to the intestinal wall hinders nutrient digestion and absorption and can allow toxins to enter the circulatory system.
Necrotic enteritis can present as either clinical or subclinical disease. The clinical form is characterized by high mortality, whereas subclinical disease causes decreased weight gain and increased feed conversion ratio (FCR). The increased FCR is due to the reduced nutrient digestibility and adsorption, resulting in compensatory feed intake.
Coccidiosis Can Increase Necrotic Enteritis Incidence
Coccidiosis is another common disease in poultry that causes a significant negative economic impact on production. It is an enteric disease caused by parasitic protozoa in the Eimeria genus. Part of the Eimeria life cycle includes invading intestinal epithelial cells, damaging the intestinal wall barrier. The damage that coccidia cause to intestinal epithelial cells promotes invasion by C. perfringens (as well as other pathogens), increasing the incidence of necrotic enteritis.
Necrotic Enteritis in Antibiotic-Free Production
Managing necrotic enteritis in an ABF production system requires detailed strategies including the use of vaccinations, diagnostic tools and natural feed additives. In some production systems, ionophores used to control coccidiosis may also be eliminated, which further heightens the importance of other management practices that keep birds free of diseases like coccidiosis and necrotic enteritis.
Management practices, such as biosecurity, sanitation, water quality and air quality, also require increased planning and monitoring in ABF systems. Reduced ventilation, increased litter moisture and poor husbandry can increase the incidence of necrotic enteritis. The quality and sanitation of eggs in the hatchery also needs to be managed well in ABF systems, so that birds have a healthy start to life.
Necrotic Enteritis Control Solutions
Along with management best practices, natural feed additives such as Varium® and Calibrin®-Z are available to help reduce the incidence of necrotic enteritis. Varium, a natural patented mineral-based feed formulation, can reduce challenges from pathogenic bacteria and their toxins, strengthen the intestinal barrier and activate the innate immune system to naturally defend against disease. In high challenge environments, Calibrin-Z, a broad spectrum biotoxin control feed additive, can be used on top of Varium to reduce the level of pathogens in the intestines that cause mortality, wet droppings, reduced feed efficiency and damage the integrity of the intestine.
Necrotic enteritis is a challenging disease for poultry producers, particularly those using an ABF production system. However, with best practice management strategies and inclusion of feed additives that promote intestinal health and function, poultry flock health can be improved, thereby reducing the risk of disease and maximizing production efficiency. To learn more about necrotic enteritis, keep checking the Education Center for other posts in the necrotic enteritis series.
A healthy, functional gastrointestinal tract that defends against pathogens and their toxins is essential for achieving peak performance in poultry and livestock. Intestinal diseases in protein production cause billions of dollars in economic loss each year, so finding effective methods to proactively protect the intestinal environment is an important task for producers, particularly for antibiotic-free (ABF) systems. Understanding how intestinal function affects the production efficiency and overall health of poultry and livestock is the first step in finding solutions to support a healthy intestinal environment. Watch our educational animated video here or read below to learn more.
Intestinal Function and Anatomy
The intestines are covered with finger-like structures called villi that increase the surface area of the intestine and whose primary function is nutrient absorption (Figure 1). The villi and the underlying tissue are also home to vast numbers of immune cells. Lining the villi are enterocytes: cells that use microvilli to absorb nutrients from the intestinal lumen into the circulatory system.
Between the enterocytes are tight junctions that regulate intestinal permeability. The enterocytes form the one-cell-thick intestinal wall which, together with a mucus covering, act as a barrier between the lumen contents and the rest of the body. To function correctly, the enterocytes need to be healthy, properly nourished and energized.
Defend Against Pathogen Invasion
The intestine does more than aid digestion and absorption; it acts as a gatekeeper, protecting the body against harmful pathogens and their toxins. The mucus and enterocytes that line the intestine form a barrier and are the first line of defense against the external environment. Therefore, if the intestinal environment is unhealthy and not functioning correctly, it can have a negative impact on multiple systems in the body.
In normal production settings, birds and livestock are exposed to pathogens through feed and the environment. Some pathogens are destroyed by the acidic environment of the stomach; however, some survive and establish within the microbiota of the small intestine. An imbalanced intestinal environment can result in an overgrowth of pathogens, which triggers the response that can lead to enteric disease (e.g., necrotic enteritis) or prevents animals from reaching their maximum production potential.
Once established, virulent strains of bacteria can secrete potent toxins during rapid cellular growth and metabolism. Lipid-like toxins can also be released from bacterial cell walls when bacteria die, either naturally, from antibiotic use or due to the immune response. The toxins disrupt the tight junctions and trigger enterocyte death, causing breakdown of the protective intestinal barrier (Figure 2). The barrier breakdown impedes nutrient digestion and adsorption, limits organ function and allows toxins to enter the circulatory system.
Natural Solutions to Maintain Intestinal Health
With the increase in antibiotic-free production systems, maintaining a healthy intestinal environment now requires a natural method to reduce the levels of pathogens in the intestinal environment. Amlan’s patented, natural mineral-based formulations, Varium® for poultry and NeoPrime® for swine, modify the intestinal environment by reducing pathogenic bacteria and their toxins, stimulating innate immune function and energizing enterocytes to create a strong intestinal barrier.
When Varium or NeoPrime are added to diets, pathogens and their toxins in the intestinal lumen are bound by Amlan’s proprietary, thermally activated mineral technology. The bound pathogens are then safely presented to the immune system via intestinal microfold (M) cells. Immune cells process these antigens and create more immune cells to naturally defend against invasion.
By presenting the bound antigens safely to the immune system before it is overwhelmed by high levels of pathogenic challenge, the immune system is thermally activated and prepared to mount a proper defense. After the pathogenic or toxin challenge is reduced, strengthening the epithelial cells that line the intestinal tract and keeping pathogens and toxins outside the body helps provide additional protection.
Maintaining a healthy intestinal environment is key to helping livestock and poultry perform to their maximum potential. Amlan can help, with next-generation mineral technology that reduces pathogenic challenges, strengthens the intestinal barrier and primes the immune system to naturally defend against disease. For more information, visit https://amlan.com/products/
Protecting gut health, maximizing feed efficiency and increasing growth rates in poultry has traditionally been achieved with antibiotic growth promoters (AGPs). But with the rise of antibiotic-resistant bacteria and consumer demand for antibiotic-free (ABF) protein, the worldwide poultry industry is migrating toward ABF production systems. Poultry producers today need viable, profitable and natural alternatives to AGPs that can help maintain gut health, support efficient feed use and promote growth.
Varium® is a natural performance additive that enhances multiple aspects of the intestinal environment, creating production results consistent with those observed with AGP use. In the intestinal lumen, Varium reduces levels of pathogenic bacteria and their toxins, protecting the intestinal lining from attack. Varium also acts an enterocyte energy source, fostering healthy and strong enterocytes that can better absorb nutrients and support growth. Additionally, Varium stimulates the innate immune system to help birds naturally defend against pathogens. Continue reading to view the research demonstrating the beneficial effects Varium has on poultry immunity and intestinal integrity.
Improved Immune Competence
Birds with a healthy gut have a competent immune system that responds appropriately and is less susceptible to disease-causing bacteria and viruses. In a study conducted with Salmonella-challenged broilers at Imunova Análises Biológicas (Curitiba, Brazil), Varium helped restore immune competence and ultimately favored the development of appropriate defenses against the pathogen. The improved immune competence was demonstrated by the apparent prevention of cytotoxic T cell terminal activation (CD8+CD28– phenotype) which, when it occurs in large numbers, can render the immune system less responsive and competent in fighting against pathogen infections. Varium also restored major histocompatibility complex class II (MHC II) expression, essential for the stimulation of an antigen‑specific immune response, and increased monocyte phagocytic activity compared to the Salmonella-challenged control group. For further details of this study, contact Amlan (email@example.com).
Responsive to Immune System Stimuli
The ability of the immune system to prevent pathogens from establishing a successful infection is vital to keeping birds healthy and productive. The immune response to various stimuli was assessed in two Varium field trials by measuring the antibody titer from two common vaccines and assessing the prevalence of bacteria in the small intestines and digesta.
In a field trial conducted at a commercial farm in Vietnam, broilers were fed a basal diet and coccidiostat with either enramycin (at the manufacturer’s recommended dose) or Varium (0.1%) for the first 28 days. From day 29 to the end of study (either day 35 or 42), the control broilers were fed the basal diet only and the Varium group was fed the basal diet plus Varium (0.1%). Sub-samples from randomly selected birds were obtained and the data analyzed at Nong Lam University, Ho Chi Minh City.
In this trial, the infectious bronchiolitis virus (IBV) antibody titer of Varium-fed broilers was significantly increased on day 15 (P < 0.05 vs. antibiotic-fed control) and similar on day 35 to the antibiotic-fed control. Newcastle disease virus (NDV) titers were also similar on days 15 and 35 in the control and Varium groups. Antibody titers indicate the strength of the acquired immune response to vaccination. These results show that Varium can stimulate an antibody production response to vaccination that is the same as or better than broilers fed AGPs.
In another trial conducted at a university in Pakistan, broilers were fed either an AGP (zinc bacitracin, 0.01%) or Varium (0.10%) for 35 days. Varium fed birds had a higher (P < 0.05) concentration of the beneficial bacteria Lactobacilli and a lower concentration of the pathogenic bacteria Salmonella in the small intestine and digesta. This demonstrates that Varium in the diet was able to maintain a healthier intestinal microbiota. The antibody titer for NDV was also greater for Varium-fed broilers than control birds (Figure 1).
Figure 1: The Newcastle disease virus (NDV) antibody titer (by hemagglutination inhibition assay) was significantly higher (P < 0.05) in Varium-fed broilers than AGP-fed broilers on day 20 (14 days after first vaccination [intraocular and subcutaneous]) and day 35 (14 days after second vaccination [oral booster]). Different letters indicate significant differences (P < 0.05) between groups within day.
Improved Intestinal Integrity
Along with immune competence, the structure and functional integrity of the intestine is also key to reducing the risk of infection. A healthy intestinal tract and competent immune system improve the ability of the bird to block the invasion of pathogens into intestinal epithelial cells and the circulatory system.
In the Imunova Análises Biológicas study, use of a fluorescent marker demonstrated that on days 4 and 8, the increased intestinal permeability observed in the Salmonella-challenged control was mitigated with the addition of Varium to the diet (Figure 2). The reduced permeability confirmed that Varium helped maintain the structural and functional integrity of the intestinal barrier. Varium also effectively reduced excessive migration and infiltration of lymphocytes into the cecal wall, which helped dampen the inflammatory damage and improved intestinal integrity seen in Varium-treated broilers.
Figure 2: Intestinal integrity as measured by the passage of a marker. Salmonella infection resulted in increased passage of a marker from the intestine to blood on days 4 and 8 following bacterial challenge, indicating impaired mucosal integrity. Compared to the Salmonella-infected control, Varium effectively mitigated increased intestinal permeability on days 4 and 8 (P < 0.05 vs. infected control). Different letters indicate significant differences (P < 0.05) between groups within day.
Necrotic Enteritis Scores
The reduction in AGP use has triggered an increase in the occurrence of necrotic enteritis in poultry flocks. Necrotic enteritis is caused by Clostridium perfringens and can cause significant production losses. In the trials conducted in Pakistan and Vietnam, the intestinal lesion score was not different between the Varium and antibiotic-fed groups, indicating that Varium was able to reduce the occurrence of necrotic enteritis to the same extent as the AGP.
Figure 3: Necrotic enteritis lesion score (Day 35) was numerically lower in broilers fed Varium versus broilers fed AGPs.
Varium: Feed Efficiency for Poultry
These trials demonstrated that replacing AGPs in broiler diets with Varium can maintain the immune response and intestinal integrity observed with AGP use and can also potentially improve them. Varium also helped restore the immune response in pathogen-challenged broilers. The direct benefits of the immunity and intestinal integrity results in the field trials was confirmed with growth performance being similar or better than broilers fed AGP. For more information on how Varium improves productivity visit, amlan.com/varium.
Broiler growers worldwide are under pressure to reduce or eliminate growth-promoting antibiotics from bird diets. Promoting intestinal health through improved nutrition and immune system stimulation can help producers successfully replace or reduce antimicrobials without sacrificing bird health or performance.
BY DR HONGYU XUE, LIFE SCIENCES DIRECTOR, AMLAN INTERNATIONAL
Completely removing or significantly reducing the use of antibiotic growth promoters (AGPs) raises many issues for broiler producers. Their foremost concerns are whether their grow-out operations can remain competitive, profitable and free from performance-robbing intestinal diseases like necrotic enteritis.
Broiler growers moving to antibiotic-free poultry production now have the advantage of hindsight, unlike those who were impacted by the first antibiotic bans of 20-plus years ago.
Since then, many compounds have been studied for their ability to replace AGPs. Prebiotics, probiotics, enzymes, organ- ic acids, minerals and other additives can be used successfully to manage gut health instead of AGPs. But, and this is a big ca- veat, these products are often used in combination and in- crease feed costs. Formulated feed additives that combine the right ingredients to replace one or more other additives and help birds grow efficiently may be just what today’s broiler producers need. Certain formulated feed additives are de- signed to use different and (ideally) synergistic modes of ac- tion to achieve desired responses. Such products are typically tested by a team of specialists to determine the optimal for- mulation so growers don’t have to experiment. Those factors help formulated products deliver value.
Intestinal health is critical
A healthy gut is essential to a healthy bird. However, the gastrointestinal (GI) tract is the site of substantial disease challenges, including pathogens like Clostridium perfringens, Escherichia coli and Salmonella spp. An effective antibiotic alternative should demonstrate activity in three areas:
The intestinal lumen to reduce bacterial disease challenges,
The intestinal epithelium to strengthen the intestinal barrier,
The gut-associated lymphoid tissue (GALT) to stimulate immune function.
Varium is used worldwide in antibiotic-free poultry production to achieve equivalent outcomes as AGPs, often replacing one or more additional feed additives being used as replacements to AGPs. Multiple controlled studies and field trials demon- strate that Varium, a proprietary formulated feed additive, can replace some or all AGPs use in broiler diets. The components of the all-natural product work synergistically to provide a multifaceted approach to supporting intestinal health and im- munity, promoting efficient feed use and improving overall flock performance, see Figure 1. Those mechanisms of action support bird intestinal health and efficiency by:
Reducing total biotoxin load, which helps protect intestinal homeostasis,
Reducing pathogen load through type-1 fimbriae bacterial adhesion,
Providing enterocytes with a preferred energy source, which enhances the intestinal barrier,
Stimulating the innate and adaptive immune responses to help birds defend against pathogens.
Trials find comparable performance
For broiler producers seeking evidence-based options, pre- adoption trial data from commercial broiler producers in Brazil demonstrate how Varium performs alone or in combi- nation with other feed additives. In a 40-day feeding trial conducted under natural challenge, 2,400 day-old chicks were assigned to one of four treatments (Table 1).
In addition to the specified treatments, all diets included common anti- coccidial treatments. Captured and calculated data included body weight, feed intake, mortality, feed conversion ratio (FCR) and percent mortality. Broilers fed diets containing Varium alone or in combination with other additives had weight gain and FCR comparable to those fed a diet contain- ing two antibiotics, a mycotoxin binder and a probiotic. No significant differences in day-40 weight gain or FCR were de- tected among treatments. However, mortality at day 40 was substantially lower for broilers consuming Varium in their di- ets. Broilers fed diets containing Varium had higher produc- tion efficiency indices (PEI) than the control group. A second trial in Brazil compared the performance of Varium to Tylosin when fed to birds at a commercial broiler grow-out operation that produced about 170,000 birds per day for slaughter. Tylosin at a rate of 55 ppm was added to diets between August 2017 and July 2018. Tylosin and a an enzyme-based mycotox- in deactivator were then removed and Varium was added at a rate of 0.1% from August 2018 through July 2019.
Captured and calculated data included body weight and age at slaughter, average daily gain, FCR, PEI, mortality and liver quality. No significant differences were detected between treatments for FCR, average daily gain, average body weight, average age at slaughter, PEI or percent mortality. Interesting- ly, faeces from broilers fed diets containing the feed additive were firmer, resulting in better quality litter than those birds receiving Tylosin in their diets, see Table 2. Better litter quality means decreased incidence of foot pad dermatitis.
Table 1 – Trial results under natural challenge. Treatments investigated in a 40-day feeding trial with natural challenge
Varium + halquinol + mycotoxin binder + B. subtilis
Va + Vir
Varium + virginiamycin + mycotoxin binder + B. subtilis
Varium (1 kg/MT)
Table 2 – Averages of key performance parameters.
Body weight (kg)
Daily gain (g)
Liver quality (%)
Tylosin + mycotoxin binder
Profitable antibiotic-free production
Intestinal health becomes more important to profitable broiler production as AGPs are removed from bird diets. But it takes the right combination of feed ingredients and additives along with many other factors. Varium is helping commercial producers save money by replacing one or more feed addi- tives in broiler diets while maintaining or improving feed conversion and weight gain and decreasing mortality. Efficient broiler production without AGPs is possible.
CHICAGO, IL—A recent study found that Varium™, the natural growth promoter for poultry from Amlan International, performed better than antibiotics alone, delivering significant reductions in mortality, and improvements in feed conversion and intestinal health, for a 10:1 return on investment.
“As the reduction or elimination of antibiotics in broiler production continues to expand worldwide, Varium is proving to be an effective way to enhance the growth-promoting abilities of antibiotics, or, when used in antibiotic-free production, to achieve bird performance equivalent to flocks receiving sub-therapeutic levels of antibiotics,” said Dr. Ron Cravens, President of Amlan International, a Nevada Corporation.
“We’re very pleased our customers’ broilers receiving Varium, experienced improved villi height and a reduction in crypt depth indicating improved intestinal integrity,” said Cravens. “It’s quite notable that an improved European Efficiency Index (EEI) score was also seen, increasing from 350 to 400 points.”
Compared to the control diet that included antibiotics, feeding Varium decreased mortality by 40%, from 6.93% to 4.18%, with improvements seen throughout the growout period, not just in young birds. Feed conversion improved 15 points, from 1.64 to 1.49, with the majority of the gains seen after day 7 and a greater response seen in female broilers.
Varium is a registered product in a variety of countries, including China and Mexico. For a full list of registered countries and a complete study of the results and more information on Varium, please visit Amlan.com. Varium is sold outside the U.S.
MEDIA CONTACT Reagan Culbertson
ABOUT AMLAN INTERNATIONAL
Oil-Dri Corporation of America (NYSE: ODC), a Delaware corporation and doing business as “Amlan International,” has grown its product offering across the intestinal health and AGP-alternative market, driven largely by the research conducted in its laboratory campus in Vernon Hills, IL. In 2013, the company’s global reach expanded with the establishment of its China subsidiary in Shenzhen. Further information on Amlan International is available at amlan.com.