Skin transcriptome analysis in Brangus cattle under heat stress

Area of Science:

• Animal Science
• Genomics
• Physiology

Background:

• Heat stress negatively impacts livestock welfare and productivity, particularly in tropical regions.
• Development of composite breeds like Brangus cattle aims to improve adaptation to heat.
• Understanding the genetic and physiological basis of heat tolerance is crucial for sustainable livestock production.

Purpose of the Study:

• To investigate gene expression profiles in Brangus cattle skin under heat stress.
• To correlate transcriptomic data with skin histological characteristics.
• To elucidate the complex mechanisms of heat stress response in cattle.

Main Methods:

• Case-control study design comparing heat-stressed and non-stressed Brangus bulls (N=5 each).
• Rectal temperature used to define heat stress conditions.
• Skin transcriptomics analysis, including differential gene expression, enrichment, and pathway analysis.
• Evaluation of correlations between breed composition, phenotypic traits, and skin histology.

Main Results:

• Identified 4309 differentially expressed genes (2113 downregulated, 2196 upregulated) in heat-stressed cattle (P < 0.01).
• Enrichment analysis revealed significant changes in pathways related to thermogenesis, metabolism, antioxidant defense, immune response, and apoptosis.
• Positive correlations observed between sweat gland number, blood vessel count, and zebuine genetic content, suggesting a role in heat dissipation.

Conclusions:

• Heat stress induces a complex physiological response in cattle, involving significant genetic and metabolic adjustments.
• Skin features, such as increased vascularization and sweat gland density, are associated with higher zebuine genetic content and contribute to heat tolerance.
• The animal's capacity to cope with heat stress is strongly influenced by its skin's structural and genetic characteristics.