Chickens in a futuristic farm, symbolizing genetic resilience.

Can Chicken Genes Beat the Heat? Exploring Genetic Resistance to Heat and Disease

Soraya Malik in Science & Nature September 2025 • 4 min read.

"New research identifies key genes that could help chickens thrive in challenging environments, offering a path to improved poultry production and global food security."

Newcastle disease remains a significant threat to poultry farming, especially in areas with limited resources. In these regions, chickens often face multiple challenges, including heat stress, which can weaken their immune systems and reduce productivity. Finding ways to help chickens withstand these combined pressures is crucial for food security and economic stability.

Traditionally, selective breeding has been used to improve poultry traits, but breeding for disease resistance and heat tolerance is complex. It requires facing biosafety concerns, the potential for animal welfare issues, and high costs. Identifying the specific genetic factors that influence resilience can greatly speed up the breeding process.

A recent study has identified genes and genetic variations (haplotypes) that affect how chickens respond to both heat and Newcastle disease. This opens new avenues for developing chickens that are genetically predisposed to perform well under harsh conditions, ultimately boosting food production and livelihoods in vulnerable communities.

Key Genes for Heat and Disease Resistance: What Did the Researchers Discover?

Chickens in a futuristic farm, symbolizing genetic resilience.

Researchers investigated specific genes known to be involved in immune responses, stress responses, and heat tolerance. These included TLR3, TLR7, MX, MHC-B, IFI27L2, SLC5A1, HSPB1, HSPA2, HSPA8, IFRD1, IL18R1, IL1R1, AP2A2, and TOLLIP. They studied a commercial egg-laying line of chickens, exposing half the birds to high temperatures before challenging them with Newcastle disease virus (NDV).

Throughout the study, scientists measured various traits related to heat and NDV responses. They then analyzed the chickens' DNA to identify single nucleotide polymorphisms (SNPs) within the target genes and determined the unique haplotypes. The team then examined how these gene haplotypes affected the chickens' responses to both NDV and heat stress.

Here's a breakdown of the key findings:

Haplotype Effects: The study identified seventeen significant haplotype effects across seven genes related to response to NDV or heat + NDV.
Identified Genes: Genes identified included TLR7, MX, IFI27L2, SLC5A1, HSPA2, IFRD1, IL1R1.
Phenotypes Observed: Researchers observed that these genes affected seven phenotypes, which included growth rate post-NDV, viral load 6 dpi, antibody 10 dpi, BE, HCO3, TCO2, PH.

The results pinpointed specific genetic variants linked to improved responses to heat and/or NDV. For instance, IFI27L2 showed a consistent effect on antibody production in NDV-challenged chickens. SLC5A1 was associated with viral load, while IFRD1 and HSPA2 affected growth rate post-NDV challenge. Furthermore, HSPA2, MX, IL1RL1 and TLR7 all had significant effects on various blood components under heat and NDV stress.

Looking Ahead: Breeding for Resilience

These findings offer valuable insights for breeding chickens that can thrive even when faced with disease and heat stress. By targeting specific genetic variants, breeders can develop more resilient and productive poultry, especially benefiting farmers in resource-limited regions. This approach could significantly enhance food security and improve livelihoods in communities that depend on poultry farming.

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Everything You Need To Know

What is Newcastle disease, and why is it such a concern for poultry farming?

Newcastle disease is a highly contagious and devastating viral disease that affects poultry. It poses a significant threat to poultry farming, especially in regions with limited resources, because it can cause high mortality rates and reduced egg production. Efforts to develop chickens genetically resistant to Newcastle disease are crucial for global food security, particularly in vulnerable communities that rely on poultry for sustenance and income. The impact of Newcastle disease extends beyond just the chickens themselves; it affects the livelihoods of farmers and the availability of a vital food source.

What specific genes did the study focus on, and what was the purpose of examining them?

The study focused on identifying specific genes and genetic variations, known as haplotypes, that influence how chickens respond to both heat stress and Newcastle disease. Researchers investigated genes involved in immune responses (such as TLR3, TLR7, MX, MHC-B, IFI27L2, IL1R1, IL18R1, and TOLLIP), stress responses (like IFRD1), and heat tolerance (including SLC5A1, HSPB1, HSPA2, and HSPA8). They pinpointed genetic variants, called single nucleotide polymorphisms (SNPs), within these genes and examined how different gene haplotypes affected the chickens' ability to withstand heat and resist the Newcastle disease virus (NDV). This is significant because understanding these genetic links allows for targeted breeding programs to enhance resilience in chickens.

What were the key findings regarding the effects of specific genes on Newcastle disease and heat stress responses?

Researchers discovered that specific haplotypes within certain genes had significant effects on the chickens' responses to Newcastle disease and heat stress. For instance, IFI27L2 consistently affected antibody production in chickens challenged with NDV, indicating its role in disease resistance. SLC5A1 was associated with viral load, suggesting its influence on controlling the virus's spread within the chicken. Additionally, IFRD1 and HSPA2 impacted growth rate post-NDV challenge, highlighting their importance in recovery from the disease. Furthermore, HSPA2, MX, IL1RL1 and TLR7 all had significant effects on various blood components under heat and NDV stress, demonstrating the interconnectedness of the response to heat and NDV.

What is selective breeding, and how can the study's findings improve selective breeding for chickens?

Selective breeding involves choosing chickens with desirable traits, such as disease resistance or heat tolerance, and breeding them to pass on those traits to their offspring. This process has been used traditionally to improve poultry. The identification of specific genetic factors influencing resilience can greatly accelerate the breeding process. Instead of relying solely on observable traits, breeders can now target specific genetic variants (SNPs) to develop chickens that are genetically predisposed to perform well under harsh conditions. This precision breeding can lead to faster and more effective improvements in poultry resilience.

How can the results of this research be used to improve poultry farming and food security?

The findings can be used to breed chickens that are more resilient to heat stress and Newcastle disease. By targeting specific genetic variants, breeders can develop poultry that are genetically predisposed to thrive even when faced with challenging environmental conditions and disease outbreaks. This approach has the potential to significantly enhance food security and improve the livelihoods of farmers in resource-limited regions, who often depend on poultry farming as a primary source of income and sustenance. This targeted breeding offers a sustainable solution for increasing poultry production in areas where heat and disease pose significant constraints.