Dr. Nikita Deshmukh
Product Manager
GrinMicro Bioscience Pvt. Ltd., Pune
8693895643
Nikita.d@grinmicro.com
Probiotics are live microorganisms that confer health benefits when administered in adequate amounts. In poultry, these beneficial bacteria play a crucial role in maintaining gut health, improving nutrient absorption, and enhancing overall bird welfare. One significant concern in commercial poultry farming is lameness—a debilitating condition that affects mobility, growth, and productivity.
Recent research has shown that probiotics can mitigate lameness by improving gut microbiota, reducing inflammation, and enhancing bone health. This article explores the potential of specific probiotic species in preventing lameness in poultry, focusing on their mechanisms of action and scientific evidence supporting their efficacy.
1. Understanding Lameness in Poultry
Lameness in poultry is a condition that results in impaired movement, difficulty in standing, and severe discomfort. It can manifest in various forms, including bacterial infections (such as bacterial chondronecrosis with osteomyelitis or BCO), tibial dyschondroplasia, and nutritional deficiencies. The primary causes of lameness include:
Bacterial Infections: Staphylococcus aureus and Escherichia coli can invade the joints and bones, leading to osteomyelitis and joint infections.
Nutritional Deficiencies: Lack of essential minerals such as calcium, phosphorus, and vitamin D can weaken bone structure.
Poor Gut Health: An imbalanced gut microbiota increases systemic inflammation, negatively affecting musculoskeletal integrity.
Environmental Stress: High stocking density and poor litter conditions can predispose birds to joint infections and footpad dermatitis.
Lameness leads to significant economic losses due to increased mortality, culling, and reduced weight gain. Addressing this issue with probiotics offers a sustainable and antibiotic-free alternative.
2. Role of Gut Microbiota in Poultry Health
The gastrointestinal tract of poultry hosts a diverse microbial population essential for digestion, immunity, and metabolic functions. A balanced gut microbiome contributes to:
Efficient nutrient absorption: Beneficial bacteria enhance the breakdown of feed and improve mineral bioavailability.
Pathogen exclusion: Healthy gut microbiota competitively inhibits the colonization of harmful bacteria such as Clostridium perfringens and Salmonella spp.
Inflammation control: A well-balanced microbiome reduces gut inflammation, which indirectly influences systemic immune responses and bone health.
Since gut health is intrinsically linked to skeletal integrity, maintaining a healthy microbiota can reduce the incidence of lameness in poultry.
3. Probiotics as a Solution for Lameness in Poultry
Lameness in poultry is a multifactorial issue, often starting from bacterial infections, poor gut health, metabolic disorders, and nutritional deficiencies. Probiotics offer a promising approach to mitigating lameness by improving gut health, enhancing nutrient absorption, modulating immune responses, and promoting bone strength. This section explores the detailed mechanisms through which probiotics contribute to the reduction of lameness in poultry.
- Competitive Exclusion of Pathogens
One of the primary ways probiotics works is through competitive exclusion, where beneficial bacteria outcompete harmful pathogens by occupying adhesion sites on the intestinal wall. Pathogenic bacteria such as Escherichia coli, Clostridium perfringens, and Staphylococcus aureus are common culprits in bacterial infections leading to lameness, particularly osteomyelitis and bacterial chondronecrosis.
Probiotics create a hostile environment for these pathogens through:
- Blocking Adhesion Sites: Beneficial bacteria like Lactobacillus acidophilus adhere to intestinal epithelial cells, preventing harmful bacteria from colonizing.
- Producing Antimicrobial Substances: Bacillus subtilis and Enterococcus faecium produce bacteriocins, organic acids, and hydrogen peroxide, which inhibit pathogen growth.
- Consuming Nutrients Before Pathogens: By depleting nutrients like iron and amino acids that pathogens rely on, probiotics starve harmful bacteria and limit their proliferation.
By reducing the overall pathogen load in the gut, probiotics indirectly decrease the risk of systemic bacterial infections that can lead to lameness.
II. Enhancement of Gut Integrity and Nutrient Absorption
A healthy gut is essential for proper nutrient absorption, particularly for minerals critical to bone development such as calcium, phosphorus, and vitamin D.
Probiotics contribute to gut integrity and improved nutrient absorption through:
- Strengthening Tight Junctions: Pathogens often cause intestinal permeability, leading to leaky gut syndrome and systemic inflammation. Probiotics like Lactobacillus reuteri enhance tight junction proteins, reducing gut permeability.
- Increasing Enzyme Activity: Bacillus subtilis produces digestive enzymes like proteases and amylases, which improve feed conversion efficiency.
- Enhancing Short-Chain Fatty Acid (SCFA) Production: SCFAs like butyrate, acetate, and propionate nourish intestinal cells, promoting better nutrient uptake and reducing gut inflammation.
Better nutrient absorption leads to stronger bones and joints, reducing the likelihood of lameness caused by metabolic disorders like tibial dyschondroplasia.
III. Modulation of the Immune System
Lameness can be exacerbated by systemic inflammation caused by infections or metabolic stress. Probiotics modulate the immune system to ensure a balanced inflammatory response.
- Reduction of Pro-Inflammatory Cytokines: Chronic inflammation in the gut or joints increases the risk of bacterial chondronecrosis. Probiotics regulate inflammatory cytokines such as IL-6 and TNF-α, preventing excessive inflammation.
- Stimulation of Mucosal Immunity: Probiotics enhance secretory IgA (sIgA) production, strengthening gut and systemic immunity against invading pathogens.
- Regulation of Gut-Associated Lymphoid Tissue (GALT): The GALT system is crucial for poultry immunity. Probiotics stimulate dendritic cells and macrophages, leading to a more robust immune response against infections.
A well-regulated immune system reduces the incidence of bacterial arthritis, osteomyelitis, and other inflammatory conditions linked to lameness.
IV. Enhancement of Bone Strength and Cartilage Development
One of the lesser-known benefits of probiotics is their ability to enhance bone metabolism and cartilage formation, which is critical in reducing leg deformities and skeletal disorders.
- Influence on Calcium and Phosphorus Metabolism: Some probiotic strains, like Bacillus coagulans, enhance the bioavailability of calcium and phosphorus by stimulating gut absorption and promoting bone mineralization.
- Collagen Synthesis for Cartilage Development: Probiotics like Lactobacillus plantarum have been shown to increase collagen type II production, which is crucial for joint and cartilage integrity.
- Reduction in Bone Resorption: Certain probiotics suppress osteoclast activity (bone-resorbing cells), preventing excessive bone loss and improving bone density.
By promoting stronger skeletal development, probiotics help reduce lameness caused by weak bones, fractures, and joint deformities.
V. Reduction of Endotoxin Load and Gut Inflammation
Endotoxins, primarily lipopolysaccharides (LPS) from Gram-negative bacteria, can trigger systemic inflammation, leading to lameness-associated conditions like bacterial chondronecrosis and osteomyelitis. Probiotics help in:
- Binding and Neutralizing Endotoxins: Lactobacillus acidophilus and Bacillus subtilis can bind LPS, preventing it from entering the bloodstream.
- Enhancing Liver Detoxification: A healthy gut microbiome reduces the burden on the liver by lowering systemic inflammatory responses.
By keeping endotoxin levels in check, probiotics reduce the likelihood of inflammatory conditions that contribute to lameness.
4. Key Probiotic Species for Preventing Lameness
I. Lactobacillus acidophilus
Key Benefits:
- Enhances intestinal barrier integrity
- Produces lactic acid to lower gut pH and prevent pathogen colonization
- Improves calcium and phosphorus absorption
Mode of Action:
Lactobacillus acidophilus is a lactic acid bacterium (LAB) known for its probiotic effects in poultry. It works by colonizing the gut and producing lactic acid, which lowers intestinal pH, creating an environment unfavorable for pathogenic bacteria such as Salmonella spp., Escherichia coli, and Clostridium perfringens (Wang et al., 2019). A healthier gut leads to better absorption of essential minerals like calcium and phosphorus, which are critical for bone development and reducing skeletal deformities (Khan et al., 2021).
Moreover, L. acidophilus stimulates the production of mucins in the gut lining, strengthening the intestinal barrier and preventing systemic inflammation. Chronic gut inflammation is linked to poor musculoskeletal health, making this probiotic particularly valuable in preventing lameness.
II. Bacillus subtilis
Key Benefits:
- Produces extracellular enzymes for enhanced digestion
- Improves bone mineralization and growth
- Reduces gut inflammation and oxidative stress
Mode of Action:
Bacillus subtilis is a spore-forming probiotic that survives harsh environmental conditions, making it ideal for poultry supplementation. It secretes proteases, amylases, and phytases that enhance the digestion of proteins, carbohydrates, and phosphorus, respectively (Hong et al., 2020). These enzymes help improve feed efficiency and ensure optimal mineral uptake for stronger bones. Furthermore, B. subtilis reduces oxidative stress in poultry by stimulating the production of antioxidant enzymes such as superoxide dismutase (SOD) and glutathione peroxidase (GPx). Oxidative stress is a key contributor to bone degeneration and lameness, making this probiotic highly beneficial (Gao et al., 2017).
A study conducted by Hossain et al. (2022) demonstrated that broilers supplemented with B. subtilis had significantly improved bone mineralization and reduced incidence of tibial dyschondroplasia—a major cause of lameness.
III. Enterococcus faecium
Key Benefits:
- Stimulates immune responses against bacterial infections
- Promotes gut homeostasis and reduces pathogen colonization
- Enhances production of short-chain fatty acids (SCFAs) for better bone metabolism
Mode of Action:
Enterococcus faecium is another effective probiotic in poultry that functions by promoting immune system activity and maintaining gut homeostasis. It produces bacteriocins, which are antimicrobial peptides that inhibit harmful bacteria such as Staphylococcus aureus and E. coli, both of which can contribute to joint infections and osteomyelitis in poultry (Zheng et al., 2021).
Additionally, E. faecium ferments dietary fibers to produce short-chain fatty acids (SCFAs), particularly butyrate and propionate. These SCFAs serve as an energy source for intestinal cells and contribute to bone metabolism by enhancing calcium absorption and reducing inflammatory responses (Gharib-Naseri et al., 2019). A trial by Yang et al. (2020) reported that chickens supplemented with E. faecium exhibited improved gait scores, better immune function, and a lower incidence of bacterial chondronecrosis with osteomyelitis (BCO), a leading cause of lameness in broilers.
IV. Pediococcus acidilactici
Key Benefits:
- Enhances nutrient utilization and feed efficiency
- Strengthens gut barrier function
- Supports collagen and cartilage synthesis
Mode of Action:
Pediococcus acidilactici is a lactic acid bacterium that enhances gut health by improving nutrient digestibility and modulating the gut microbiome. It produces exopolysaccharides that reinforce gut barrier function and reduce systemic inflammation.
This probiotic also plays a role in bone and joint health by stimulating the production of glycosaminoglycans, which are essential for cartilage formation. Healthy cartilage reduces joint degeneration, lowering the risk of lameness in fastgrowing broilers.
A study by Lalonde et al. (2021) found that birds supplemented with P. acidilactici had improved bone mineral density, stronger joints, and better weight distribution on their legs.
5. Lactobacillus reuteri
Key Benefits:
- Inhibits pathogenic bacteria in the gut
- Produces bioactive compounds that improve bone density
- Enhances overall skeletal health
Mode of Action:
Lactobacillus reuteri is known for its ability to produce reuterin, an antimicrobial compound that inhibits pathogens responsible for gut infections. Since infections can lead to systemic inflammation and osteomyelitis, using L. reuteri helps mitigate these risks (Santos et al., 2019).
Additionally, L. reuteri has been shown to stimulate bone-forming cells (osteoblasts) while reducing bone-resorbing cells (osteoclasts), leading to improved bone density and reduced skeletal disorders (Schwarzer et al., 2017).
5. In-Depth Mode of Action of Probiotics in Reducing Lameness
5.1 Improvement of Gut Health and Nutrient Absorption
Probiotics improve gut health by increasing beneficial bacterial populations and enhancing the digestion of complex feed components. This ensures efficient absorption of minerals essential for bone strength, such as calcium and phosphorus.
5.2. Reduction of Inflammatory Responses
Probiotics reduce systemic inflammation by modulating cytokine production. They suppress pro-inflammatory cytokines like IL-6 and TNF-α while promoting anti-inflammatory cytokines such as IL-10, preventing joint and bone inflammation.
5.3. Strengthening of Bone and Cartilage Development
Probiotic strains like Bacillus subtilis produce extracellular enzymes that aid in calcium metabolism, promoting stronger bones. Additionally, probiotics enhance collagen production, crucial for cartilage development.
5.4. Modulation of the Immune System
By enhancing mucosal immunity, probiotics improve the bird’s ability to fight off infections that contribute to lameness. This includes stimulation of secretory IgA and the activation of macrophages that eliminate bacterial pathogens.
6. Scientific Studies Supporting Probiotic Use
Several studies have demonstrated the efficacy of probiotics in reducing lameness. Research indicates that probiotic supplementation in broilers leads to improved gait scores, reduced bacterial infections, and better bone mineralization.
7. Probiotic Supplementation Strategies
Dosage: Optimal probiotic concentration depends on the strain used, typically ranging from 10⁶ to 10⁹ CFU/g of feed. Administration Methods: Can be provided through feed, water, or direct spraying onto chicks. Synergistic Effects: Combining probiotics with prebiotics enhances their beneficial effects, leading to better gut colonization.
9. Challenges and Future Prospects
Variability in Probiotic Efficacy: Different strains have different effects, requiring strain-specific research.
Need for Advanced Probiotic Technologies: Microencapsulation can improve probiotic stability and viability.
Emerging Trends: Synbiotics (probiotics + prebiotics) and genetically modified probiotics are being explored for enhanced benefits.
9. Conclusion
Probiotics offer a multifaceted approach to reducing lameness in poultry by improving gut health, preventing bacterial infections, modulating immune responses, enhancing bone strength, and reducing systemic inflammation. Their ability to improve nutrient absorption and gut integrity makes them a promising alternative to antibiotics in modern poultry farming. However, strain-specific research is necessary to optimize their efficacy for targeted health benefits. By implementing probiotic-based supplementation strategies, poultry farmers can significantly reduce lameness, improve bird welfare, and enhance overall production efficiency.