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Transcriptome analysis reveals potential mechanisms underlying differential heart development in fast- and
Jibin Zhang1, Carl J Schmidt2, Susan J Lamont3
1Department of Animal Science, Iowa State University, 806 Stange Rd, 2255 Kildee Hall, Ames, IA, 50011, USA.
BMC Genomics
|April 15, 2017
Summary
Fast-growing broilers suffer heat-related heart failure due to smaller hearts. Breeding for heat tolerance requires understanding genes affecting cardiac development and function under heat stress.
Area of Science:
- Animal Science
- Genomics
- Physiology
Background:
- Modern fast-growing broilers exhibit susceptibility to heat stress-induced heart failure.
- Their cardiac capacity is limited by relatively small hearts unable to meet increased blood pumping demands.
- Identifying genes and pathways influencing cardiac development and heat-related dysfunction is crucial for breeding heat-tolerant poultry.
Purpose of the Study:
- To investigate the genetic and molecular mechanisms underlying cardiac dysfunction in fast-growing broilers under heat stress.
- To compare the responses of a fast-growing broiler line (Ross 708) and a slow-growing line (Illinois) to heat stress.
- To identify potential genetic targets for improving heat tolerance and cardiac function in broilers.
Main Methods:
- Two broiler lines (Ross 708 and Illinois) were subjected to heat stress (35-37°C) or thermoneutral conditions from 21 to 42 days posthatch.
- Body and heart weights were measured.
- Left ventricle gene expression was analyzed using RNA-sequencing (RNA-seq).
- Differential gene expression and pathway analysis (Ingenuity Pathway Analysis - IPA) were performed.
Main Results:
- Heat stress reduced body weight and normalized heart weight in Ross 708 broilers, but not in Illinois broilers.
- RNA-seq identified 325 differentially expressed genes in Ross 708 under heat stress, compared to only 3 in Illinois.
- IPA revealed significant downregulation of cell cycle activity, particularly "Mitotic Roles of Polo-like Kinases," in Ross broilers under heat stress.
Conclusions:
- Fast-growing broilers' increased susceptibility to heat stress-induced cardiac dysfunction may stem from diminished heart capacity and reduced relative heart size.
- Transcriptome analysis suggests decreased cell cycle activity and increased apoptosis contribute to smaller relative heart size in heat-stressed Ross broilers.
- Identified differentially expressed genes and pathways offer potential targets for breeding heat-tolerant broilers with improved cardiac function.