Álvaro García
There’s an increasing interest in probiotics as a viable substitute for antibiotics in beef and dairy cattle diets. These live microorganisms—like Lactobacillus spp., Saccharomyces cerevisiae, Bifidobacterium spp., and especially Bacillus spp.—are gaining attention for their potential health benefits. Gram-positive, spore-forming, aerobic, and facultative anaerobic, Bacilli have drawn focus due to their observed benefits in monogastric animals. Recent reviews have highlighted their potential in pathogen inhibition, immune system stimulation, and improvements in nutrient utilization. Additionally, certain Bacillus spp. produce enzymes aiding digestion, potentially enhancing animal performance.
These probiotics, comprising beneficial bacteria, offer an interesting alternative to antibiotics. They help maintain a balanced gut microbiome, enhancing digestion and fostering growth. Some studies even suggest their role in reinforcing the animals’ immune systems, potentially reducing the incidence of illnesses. Incorporating probiotics can establish a strong population of beneficial gut bacteria, reducing gastrointestinal issues. Current research is exploring Bacillus subtilis and licheniformis combinations, showing promise in balancing gut bacteria and promoting growth. Notably, research hints at the potential of B. subtilis in boosting the immune system and aiding in vital vitamin production.
Enhancing Immunity
Recent studies suggest that Bacillus subtilis and licheniformis may influence macrophages by potentially aiding in the formation of Macrophage Extracellular Traps (METs) and modulating specific components critical for this process. Macrophage Extracellular Traps, like Neutrophil Extracellular Traps (NETs), are composed of chromatin (DNA and histones), and antimicrobial proteins, serving as a defense mechanism to trap and neutralize pathogens, thus hindering their spread and facilitating elimination from the body.
When a macrophage encounters a pathogen, it can deploy METs, ejecting their chromatin and antimicrobial contents into the surrounding environment. These traps entangle and immobilize pathogens, impeding their spread and facilitating their elimination from the body. The release of METs is a crucial immune response, providing an additional line of defense against invading microorganisms. By immobilizing and neutralizing pathogens, METs contribute to the body’s ability to combat infections and protect against disease.
Bacillus subtilis and licheniformis might initiate or enhance MET formation by influencing key components involved in this process. For instance, they may impact histone citrullination, a modification affecting chromatin structure and immune responses. By altering these mechanisms Bacillus could potentially enhance macrophage responses to pathogens, improving their ability to form these extracellular traps.
Furthermore, Bacillus might also contribute to the production of myeloperoxidase. Myeloperoxidase is an enzyme found in certain types of immune cells, particularly in neutrophils and some types of macrophages. It plays a crucial role in the generation of reactive oxygen species as part of the immune response. When the immune system detects foreign invaders, such as bacteria or viruses, neutrophils and macrophages are recruited to the site of infection. These immune cells engulf the pathogens in a process called phagocytosis. Inside the phagosomes, myeloperoxidase is released and becomes part of a system that produces various reactive oxygen species, primarily hypochlorous acid from hydrogen peroxide and chloride ions in the presence of myeloperoxidase and other reactive intermediates. This generation of reactive oxygen species, particularly hypochlorous acid, is highly effective in killing and neutralizing invading microorganisms. Reactive oxygen species can damage the DNA, proteins, and membranes of pathogens, disrupting their cellular functions and contributing to their elimination from the body.
Excessive or uncontrolled production of reactive oxygen species, however, can also cause damage to the body’s own cells and tissues, leading to oxidative stress and inflammation. Therefore, while myeloperoxidase and reactive oxygen species play a crucial role in the immune response against pathogens, their balance and regulation are essential to prevent collateral damage to the host cells. This process could potentially aid in the creation of METs by macrophages, strengthening the body’s defense against infections.
In summary, while the precise mechanisms are still under investigation, Bacillus subtilis and licheniformis show promise in influencing immune responses, particularly in aiding macrophages by potentially enhancing MET formation—an essential aspect of the body’s defense against infections.
Positive Impact on Feed Digestibility and Efficiency
Bacillus subtilis and Bacillus licheniformis coexist and sometimes complement each other’s functions in maintaining gut health and improving animal performance. While their relationship may not resemble classical symbiosis, their coexistence in the gut microbiota can positively contribute to overall gut health and animal well-being. These bacillus example trigger a higher release of DNA and increased production of reactive oxygen species, potentially contributing to effective clearing pathogenic organisms.
Both Bacillus species have been studied for their potential role in improving feed digestibility in various animals, including ruminants. These probiotics, when added to animal diets, have shown promising effects on nutrient utilization and digestive processes.
Studies suggest that Bacillus subtilis and licheniformis can enhance the breakdown of complex nutrients like fiber, starch, and protein in the feed. They produce enzymes such as amylases, proteases, and cellulases, which aid in the digestion of carbohydrates, proteins, and fibers, respectively. By secreting these enzymes, these probiotics assist in breaking down the feed components into simpler forms that are more easily absorbed by the animal’s digestive system.
Moreover, these Bacillus strains have been found to promote a healthy gut environment by modulating the microbial composition in the digestive tract. By enhancing the population of beneficial bacteria and suppressing harmful pathogens, they contribute to improved gut health and function. A healthier gut environment can lead to better nutrient absorption and utilization from the feed.
Research has also shown that Bacillus subtilis and licheniformis can positively influence the fermentation processes occurring in the animal’s gut. This improved fermentation can lead to increased production of short-chain fatty acids that serve as an energy source for the animal and contribute to better nutrient absorption.
University Research results
In a 2022 University of Queensland experiment, a Bacillus-based probiotic was evaluated for its impact on forage and high-starch concentrate digestibility. The DFM, containing B. licheniformis and B. subtilis, significantly enhanced in vitro dry matter (DM) and neutral detergent fiber (NDF) digestibility across diverse forage sources, varying in crude protein (CP) and NDF content. Moreover, it notably improved in vitro starch digestibility (IVSD) in various cereal grains like high- and low-density barley, corn, sorghum, and wheat. These enhancements likely stemmed from increased enzymatic activity, modulation of gut microbiota, and improved gastrointestinal fermentation, promising better nutrient utilization and overall animal health.
In a separate study at the University of Lavras, Brazil, the same Bacillus-based probiotic was investigated in live cattle. Although no significant differences were observed in initial and final body weight, average daily gain, hot carcass, or dressing, bulls on the probiotic diet showed a 4% reduction in dry matter intake and a notable 6.3% increase in the feed efficiency ratio (G:F). This supplementation displayed promising potential for enhancing feed efficiency in feedlot cattle without major alterations in other measured parameters.
The referenced studies underscore the potential of Bacillus subtilis and licheniformis in enhancing beef cattle nutrition. Their combination demonstrates a notable ability to influence macrophage responses, strengthening the body’s defense against infections. Moreover, they substantially impact the gut’s nutrient utilization dynamics, improving digestion and nutrient absorption. These insights obtained from diverse geographical studies highlight the promising role of Bacillus-based probiotics in enhancing nutrient utilization, reinforcing immune responses, and ultimately improving overall animal performance in cattle.
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