Unraveling the Impact of Heat Stress on Gut Microbiota in Broiler Chickens: A Bibliometric and Literature Review

As climate change intensifies, heat stress poses a significant challenge to sustainable poultry production, threatening global food security and animal welfare. Broiler chickens, genetically selected for rapid growth and efficient feed conversion, are particularly susceptible to heat stress, which disrupts their physiological balance and impairs intestinal health. Although the role of gut microbiota in food metabolism and immune function is well-established, the impact of heat stress on microbial dynamics in broilers remains inadequately understood. This review synthesizes bibliometric and literature analyses to explore the current state of research on heat stress and gut microbiota in poultry. Data were systematically gathered from the Web of Science and Scopus, yielding 80 relevant publications from 2004 to February 2025. Research output has notably increased since 2015, with China, Egypt, and the United States emerging as leaders in publication volume and impact. Key findings indicate that heat stress induces gut dysbiosis, characterized by a reduction in beneficial bacteria (e.g., Lactobacillus and Bifidobacterium) and an increase in pathogenic taxa (e.g., Clostridia and Salmonella), resulting in impaired nutrient absorption, compromised gut barrier function, and heightened disease susceptibility. Intervention studies suggest that dietary supplementation with probiotics and phytochemicals can partially restore microbial balance and improve performance under heat stress. However, significant gaps persist in understanding the long-term effects of chronic heat exposure, genotype-environment interactions, and the potential of multi-omics approaches. Future research should prioritize developing heat-resistant poultry strains, refining nutritional and environmental management strategies, and identifying cost-effective solutions to sustain productivity and animal welfare amid a changing climate.