Probiotics in Poultry Nutrition: Enhancing Health, Performance, and Sustainability

Isaac Mugweru

Researcher

11 min read
17/12/2024
Probiotics in Poultry Nutrition: Enhancing Health, Performance, and Sustainability

Introduction

The global poultry industry has experienced substantial growth, driven by an increasing demand for poultry products. Poultry are highly efficient at converting feed, achieving feed conversion ratios between 1.6 and 2.0 (Diaz Carrasco et al., 2019). However, the industry faces challenges, including the increasing prevalence of antibiotic-resistant bacteria and growing consumer demand for antibiotic-free poultry products (Adhikari et al., 2020). The gut microbiota plays a crucial role in poultry health and performance. A balanced gut microbiota in poultry contributes to efficient nutrient digestion and absorption, proper immune function, and overall well-being (Shini & Bryden, 2021). Disruptions to this delicate balance, known as dysbiosis, can negatively impact bird health and productivity (Fathima et al., 2022). These issues highlight the need for sustainable alternatives to maintain poultry health and productivity.

Probiotics, also known as direct-fed microbials (DFMs), are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host (Fathima et al., 2022). Probiotics work by modulating the gut microbiota, enhancing the balance and diversity of beneficial microorganisms (Arif et al., 2021). They achieve this through the competitive exclusion of pathogens, the production of antimicrobial substances, and the modulation of the host’s immune system (Pender et al., 2017). The potential benefits of using DFMs in poultry production are numerous:

  • They can improve growth performance, enhance feed efficiency, strengthen immune function, and reduce susceptibility to diseases (Lokapirnasari et al., 2020). 
  • Probiotics can also improve the oxidative status of broiler chickens (Shini & Bryden, 2021). 
  • Probiotics have emerged as a viable alternative to antibiotics in poultry production, particularly after the European Union banned the use of antibiotics as growth promoters (Adhikari et al., 2020; Fathima et al., 2022).

This article will evaluate the use of DFMs in poultry nutrition. It will focus on the efficacy of probiotics and DFMs in promoting poultry health, enhancing performance, and contributing to a more sustainable poultry industry.

The Crucial Role of the Gut Microbiota in Poultry Health

The gastrointestinal tract of poultry is home to a complex and diverse community of microorganisms known as the gut microbiota ( Shang et al., 2018; Diaz Carrasco et al., 2019;). This microbiota comprises hundreds of bacterial species, with Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria being the dominant phyla (Diaz Carrasco et al., 2019). The composition of the microbiota varies along the digestive tract, with different microbial profiles found in the crop, gizzard, ileum, cecum, and colon (Cervantes, 2015). This microbial community plays a vital role in maintaining the health and productivity of poultry by impacting various physiological processes.

One of the crucial functions of the gut microbiota is nutrient digestion. Microbes assist in the breakdown of complex carbohydrates, proteins, and lipids that the host enzymes cannot fully digest (Fathima et al., 2022). This fermentation process releases short-chain fatty acids (SCFAs), particularly in the cecum, which serve as an energy source for the host and enhance nutrient absorption ( Yadav & Jha, 2019; Guo et al., 2021). It is true to say that microbiota's role in nutrient digestion directly influences feed efficiency and growth performance in poultry.

Beyond digestion, the gut microbiota is deeply intertwined with the host's immune system. It stimulates the development and maturation of the immune system by interacting with immune cells in the gut (Shang et al., 2018; Yadav & Jha, 2019; Shini & Bryden, 2021). This interaction leads to the production of antibodies and cytokines, which are crucial components of the immune response that protect the bird against pathogens (Shini & Bryden, 2021; Fathima et al., 2022). In other words, the gut microbiota acts as the first line of defense, training the immune system to recognize and respond effectively to potential threats.

Another critical function of the gut microbiota is maintaining the integrity of the intestinal epithelial barrier (Diaz Carrasco et al., 2019). This barrier acts as a physical and chemical defense, preventing harmful microorganisms and toxins from crossing into the bloodstream. A healthy microbiota helps preserve this barrier, reducing the risk of systemic infections and promoting overall health (Shini & Bryden, 2021).

Unfortunately, this delicate balance of the gut microbiota can be disrupted, leading to a condition known as dysbiosis (Fathima et al., 2022). 

What is Dysbiosis?

Dysbiosis is an imbalance in the composition and function of the microbiota. It can impair nutrient digestion and absorption, leading to reduced feed efficiency and growth rate. This can have a detrimental effect on overall poultry performance (Cervantes, 2015). Moreover, dysbiosis can compromise the immune system, making the bird more susceptible to enteric diseases like coccidiosis and necrotic enteritis ( Cervantes, 2015; Adhikari et al., 2020; Shini & Bryden, 2021; Fathima et al., 2022). This increased vulnerability to diseases and reduced nutrient utilization can significantly impact poultry productivity. Scientists and farmers alike are increasingly recognizing the importance of maintaining a balanced and healthy gut microbiota for optimal bird health, welfare, and performance ( He et al., 2019; Xiang et al., 2019; Arif et al., 2021).

Effects of Probiotics on Poultry Growth Performance

Probiotic supplementation has been shown to influence growth performance in broilers positively. Studies have demonstrated that probiotics can improve body weight gain, feed conversion ratio (FCR), and carcass quality (He et al., 2019; Kazemi et al., 2019). Probiotics enhance nutrient digestion and absorption by increasing the activity of digestive enzymes (Kazemi et al., 2019; Fathima et al., 2022) and producing metabolites, such as organic acids, which enhance nutrient retention (He et al., 2019; Fathima et al., 2022). This improved nutrient utilization leads to better growth rates and feed efficiency. In addition, probiotics can positively modulate the gut microbiota, reducing the colonization of pathogenic bacteria and promoting the growth of beneficial bacteria (Alizadeh et al., 2017; Shini & Bryden, 2021). A healthy gut microbiota further contributes to improved nutrient digestion and absorption, ultimately resulting in enhanced growth performance.

Effects of Probiotics on Egg Production

In laying hens, probiotics have been reported to enhance laying performance and egg quality (Neijat et al., 2019; Mikulski et al., 2020). Supplementation with probiotics can lead to increased egg production, improved egg weight, and enhanced eggshell quality. A study using Pediococcus acidilactici found that probiotic supplementation increased egg weight, relative eggshell weight, and eggshell thickness while significantly improving FCR (Mikulski et al., 2020). These improvements can be attributed to the probiotic's ability to enhance nutrient absorption and utilization, leading to better egg formation and eggshell mineralization.

Effects of Probiotics on Immune Function of Poultry

Probiotics play a vital role in modulating the immune function of poultry. They enhance the bird's immune response against pathogens by stimulating both the innate and adaptive immune systems (Diaz Carrasco et al., 2019). Probiotics can increase the production of antibodies, which are essential for neutralizing pathogens (Kazemi et al., 2019; Neijat et al., 2019). They also modulate the production of cytokines, signaling molecules that regulate immune responses and inflammation (Mikulski et al., 2020; Zaghari et al., 2020). A robust immune system, supported by probiotic supplementation, helps birds fight off infections, reducing disease incidence and mortality.

The specific effects of probiotics and DFMs on poultry performance can vary depending on several factors. These factors include the strain of the probiotic, dosage, route of administration, age of the birds, and the overall health status of the flock (Shini & Bryden, 2021; Fathima et al., 2022). Therefore, it is crucial for producers to carefully select the appropriate probiotic product and administration method for their specific production system and objectives. Further research is needed to understand better the complex interactions between different probiotic strains, host genetics, and environmental factors to optimize their use in poultry production.

Research Needs and Challenges of Using Probiotics in Poultry Production

The poultry industry is continuously exploring alternatives to Antimicrobial Growth Promoters (AGPS), with probiotics emerging as prominent contenders. These feed additives offer several benefits, including improved growth performance, enhanced immune function, and reduced reliance on antibiotics. However, alongside their potential, challenges and limitations exist that warrant further investigation.

Despite promising results, further research is necessary to optimize the use of probiotics and DFMs in poultry production. One area requiring investigation is the impact of probiotic administration methods. Current methods include in-feed supplementation, addition to drinking water, and in ovo injection. Each method has advantages and limitations, and research is needed to determine the most effective approach for different production systems and bird ages. For example, in-ovo injection, which involves delivering probiotics directly into the developing embryo, has shown promise in influencing the early colonization of the gut microbiota, potentially offering long-term benefits (Pender et al., 2017).

The efficacy of probiotics can be influenced by a myriad of factors, including the probiotic strain, dosage, diet composition, bird age, and environmental stressors (Brugaletta, 2023; Oladokun & Sharif, 2024). A better understanding of these interactions is crucial for developing tailored probiotic strategies for specific production scenarios. Research should also focus on identifying reliable biomarkers that can accurately assess the efficacy of probiotics. This would allow producers to monitor the impact of probiotic supplementation on gut health, immune function, and overall bird performance.

Challenges and Limitations

Several challenges and limitations currently hinder the widespread adoption of probiotics in poultry production. One significant challenge is the variability in probiotic efficacy. Different probiotic strains possess distinct mechanisms of action, and their effectiveness can vary considerably (Krysiak et al., 2021; Yaqoob et al., 2021). This inconsistency can make it challenging for producers to select the most appropriate probiotic product for their specific needs. Additionally, the production and storage of probiotics can be complex, requiring stringent quality control measures to ensure product stability and viability.

Another limitation is the lack of direct evidence demonstrating the colonization of probiotic species post-supplementation. While probiotics can transiently increase the concentration of beneficial bacteria in the gut, their ability to establish a long-term, stable population remains unclear (Fathima et al., 2022). Advanced genome-based techniques are needed to accurately quantify the survival and colonization of supplemented probiotics.

Finally, consumer perception and market acceptance can also pose challenges. Despite the scientific evidence supporting the benefits of DFMs, some consumers may perceive them as less effective than AGPs. Educating consumers about the benefits and safety of these feed additives is crucial for promoting their wider acceptance.

Scientists and farmers should continue to collaborate to overcome these challenges and fully realise the potential of probiotics and other DFMs in poultry production. By addressing these limitations and optimising their use, probiotics and DFMs can play a pivotal role in ensuring a sustainable and profitable poultry industry.

Conclusion

Probiotics are a possible solution to the poultry industry's need to reduce antibiotic use while keeping birds healthy and productive. Probiotics, which are good microorganisms, may improve growth, boost the immune system, and lower the number of pathogens. Probiotic use may lead to better weight gain, feed conversion ratios, egg production, and immune responses. However, the efficacy of probiotics may be influenced by factors such as the strain, dose, delivery method, bird's age, and the health of the whole flock. More research is needed to understand how probiotics work with the host and environment.

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