Impact of gut microbiota structure in heat-stressed broilers

Area of Science:

• Animal Science
• Microbiology
• Environmental Science

Background:

• Gut microbiota are crucial for host health in animals.
• The impact of heat stress on chicken gut microbiota remains largely unexplored.
• Understanding these effects is vital for poultry production and welfare.

Purpose of the Study:

• To investigate the effects of heat stress on broiler chicken caecal microbiota composition.
• To assess the influence of heat stress on growth performance, HSP70, and cortisol levels.
• To identify specific microbial taxa affected by heat stress.

Main Methods:

• Broiler chickens were exposed to control (24-26°C) and heat stress (34-38°C) conditions for 28 days.
• Caecal contents were collected at multiple time points (days 1, 3, 7, 14, 28).
• 16S rRNA gene sequencing (V3-V4 region) was used for high-throughput sequencing analysis of gut microbiota.

Main Results:

• Heat stress significantly reduced average daily gain and feed intake, while increasing the feed conversion ratio.
• Serum HSP70 and cortisol levels were significantly elevated under heat stress conditions.
• Heat stress altered gut microbiota composition, decreasing Bacteroidetes and Cyanobacteria while increasing Firmicutes, Tenericutes, and Proteobacteria at the phylum level.

Conclusions:

• Heat stress significantly alters the gut microbiota composition in broiler chickens.
• Specific bacterial phyla (e.g., Firmicutes, Bacteroidetes) and genera (e.g., Lactobacillus, Bacteroides) were notably affected.
• These microbial shifts provide a basis for understanding and potentially mitigating the negative impacts of heat stress in poultry.