A functional genomics study on the acute heat stress response in the hypothalamus of Taiwan country chickens

• Main Authors: Wei-Lin Tu, 涂瑋霖
• Other Authors: San-Yuan Huang
• Format: Others
• Language: en_US
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/a5866u

博士 === 國立中興大學 === 動物科學系所 === 106 === Heat stress causes economic loss in poultry production. The hypothalamus is a crucial center for regulating body temperature, detecting temperature changes, and modulating the autonomic nervous system and the endocrine loop for heat retention and dissipation. The purpose of this study was to investigate the global profile of gene and protein expressions in the hypothalamus of a layer-type L2 strain and a meat-type B strain Taiwan country chickens (TCCs) after acute heat stress. Twelve 30-wk-old hens of TCCs were allocated to four groups. Three heat-stressed groups were subjected to acute heat stress at 38°C for 2 hr in B strain TCCs and 36°C for 4 hr in L2 strain TCCs without recovery (H2R0), with 2 hr of recovery (H2R2), or with 6 hr of recovery (H2R6), respectively. Control hens were maintained at 25°C. The hypothalamus samples were collected for mRNA expression and protein expression analysis at each time point. The results showed that the respiratory rate and body temperature of both strains increased during heat stress (P ＜ 0.05). In B strain TCCs, whole-genome microarrays analysis showed upregulated expression of 24, 11, and 25 genes and downregulation of 41, 15, and 42 genesin H2R0, H2R2, and H2R6 groups, respectively. Most of the differentially expressed genes are involved in biological processes of cellular processes, metabolic processes, localization, multicellular organismal processes, developmental processes, and biological regulation. Six of 7 genes with differential expressions in B strain TCCs by qRT-PCR were consistent with the results of microarray analysis. Results of two-dimensional difference gel electrophoresis revealed 134 protein spots differentially expressed in the hypothalamus of L2 strain TCCs after heat stress (P ＜ 0.05). Peptide mass fingerprinting analysis revealed that these spots belong to 118 distinct proteins. A total of 114 protein spots representing 71 distinct proteins were differentially expressed in the hypothalamus of B strain TCCs after acute heat stress. Most of the differentially expressed proteins are involved in biological processes of cellular processes, metabolism, transport, and cellular component organization. Results of functional genomics analysis suggested that acute heat stress may cause ischemia, protein dysfunction, and the accumulation of reactive oxygen species in mitochondria then cause damage the hypothalamic cells. The changes of transcripts and protein levels within the hypothalamic neuronss reflact a regulatory response to sustain their cellular integrity, DNA damage repairing, and processes of cell division and regeneration to attenuate the detrimental effects by acute heat stress. The major energy supply for these protective actions apparently are derived from glycolysis. Thus the differential gene expressions act as essential and unique key factors in the acute heat stress response of the hypothalamus in chickens.