P0658
Distinct Cardiac Responses to Heat Stress Between Two Broiler Lines Identified By Transcriptome Analysis

Jibin Zhang , Iowa State University, Ames, IA
Carl J. Schmidt , University of Delaware, Newark, DE
Susan J. Lamont , Iowa State University, Ames, IA
Prolonged exposure to high temperature can significantly increase metabolism, depress appetite, reduce meat production and raise mortality in broilers. Because the cardiovascular system plays an important role to dissipate heat and transport oxygen, strong cardiac function is indispensable for birds to survive under heat stress. However, due to small hearts relative to body weight, modern broilers have high risk of heart failure at high temperature.

In this study, a Ross 708 line (modern broilers) and a Heritage broiler line (relaxed selection since the 1950s) were subjected to heat stress at 35℃  for 7 hours/day from 21 to 42 days posthatch and compared to control groups kept at ambient temperature. Twenty-three libraries generated from left ventricles averaged 10 million 50-base pair single-end reads after transcriptome sequencing, trimming and filtering.

After differential expression analysis, more than 300 differentially expressed genes between heat-stressed and control birds were identified in modern broilers, while only three genes were differentially expressed in heritage broilers at a significance level of False Discovery Rate (FDR)<0.1 and log2 fold-change (LFC)>1. By Ingenuity Pathway Analysis (IPA), the significantly differentially expressed genes in modern broilers are mainly involved in apoptosis, cell proliferation, cell migration and inflammatory response. In heart disease, those genes are highly related to ventricular hypotrophy, cardiac arrhythmia and tachycardia.  This information provides insights into mechanisms of susceptibility of modern broilers’ heart to heat stress and a foundation for future genomic selection in broilers to improve their adaptation to global climate change.

Support: USDA-NIFA-AFRI grant and Hatch project #5358.

Handouts
  • PAG poster_Jibin Zhang.pdf (204.4 kB)
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