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Binding Bacterial and Fungal Toxins

Calibrin-Z logo with chickens in background.

Source: Poultry World, February 25, 2022

One of the biggest challenges for the poultry industry, especially after the removal of in-feed antibiotics, is bacterial enteritis, and in particular, necrotic enteritis caused by pathogenic Clostridium perfringens. Add production losses associated with mycotoxin-contaminated feed, and you have two industry challenges that need a natural control solution.

Calibrin-Z from Amlan International provides natural protection against field challenges, optimizing animal performance and boosting your bottom line. It is a highly efficacious, mineral-based feed additive that adsorbs a broad spectrum of bacterial toxins and mycotoxins in the intestinal tract of chickens. Unlike comparable products, Calibrin-Z binds both polar and nonpolar mycotoxins as well as bacterial toxins like alpha-toxin and NetB toxin that are produced by C. perfringens.

Read more here.

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Intestinal Health Is Key for Maximizing Production Value and Efficiency

Computer-generated illustration of gut bacteria.

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.

Illustration of a healthy intestine.
Figure 1: Anatomy of a healthy intestine

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.

Illustration of an unhealthy intestine.
Figure 2: A weakened intestinal barrier where bacteria and toxins have overcome the cellular defense mechanisms and weakened enterocytes cannot effectively function.

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

Varium®: An Effective Alternative to AGPs for Poultry Immunity and Intestinal Integrity

Computer-generated illustration of intestinal bacterial activity in poultry.

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 (

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,