Ileal microbial composition in genetically distinct chicken lines reared under normal or high ambient temperatures

Area of Science:

• Poultry Science
• Microbiology
• Animal Genetics

Background:

• Heat stress (HS) detrimentally affects poultry productivity, health, and welfare, leading to economic losses.
• Broiler chickens are especially vulnerable to HS due to their high metabolic rate and rapid growth.
• Intestinal microbiota plays a crucial role in host physiology and may mitigate HS effects.

Purpose of the Study:

• To compare the changes in ileal (IL) microbiota composition in four different broiler genetic lines under heat stress conditions.
• To investigate the influence of host genetics and heat stress on the ileal microbiota.

Main Methods:

• Four broiler lines (Giant Jungle Fowl, Athens Canadian Random Bred, 1995 Random Bred, Modern Random Bred) were subjected to thermoneutral or cyclic heat stress from day 29 to 56.
• Ileal luminal content and mucosal scrapings were collected for 16S rRNA gene sequencing.
• Microbiota diversity, composition, and predicted functions were analyzed using QIIME2, SILVA database, and PICRUSt 2.

Main Results:

• Heat stress significantly increased the Shannon index in the ileal mucosa.
• Microbial community structure differed significantly between genetic lines and conditions, particularly in the ileal mucosa.
• Genetic line had a more pronounced effect on ileal microbiota composition than heat stress.
• Predicted microbial functions were not affected by heat stress but varied significantly between genetic lines (e.g., L2015 vs. JF).

Conclusions:

• Broiler genetic line and temperature interact to influence ileal microbiota diversity and composition.
• Host genetics significantly impact ileal microbiota composition and predicted functions.
• Findings are crucial for developing nutritional strategies to maintain gut microbial balance and mitigate HS effects on broiler health and performance.