The comparative analysis of phenotypic and whole transcriptome gene expression data of ascites susceptible versus ascites resistant chickens
Ascites syndrome (AS) is a metabolic disorder that mainly occurs at later ages of meat-type chickens. Despite many research, there is no consensus about the origin of this syndrome. Our main purpose were to investigate the syndrome using both phenotypic and RNA-Seq data to elucidate the most causative factors predisposing the birds to AS. Phenotypic data analysis showed that AS indicator traits (AITs) were moderate to high heritable. Inexistence of consistent direct genetic correlation between AITs and growth related traits, indicated that neither faster growth rate nor heavier body weight is the most causative factor affecting the susceptibility of broilers to AS. However, respiratory capacity was revealed to be the most probable factor predisposing the birds to AS, as both lung weight and lung percentage were negatively correlated with AITs. Transcriptomic data analysis revealed 125 differentially expressed genes (DEGs) between the ascitic and healthy groups. Up-regulated genes in ascitic group enriched mainly in gas transport biological process, while down-regulated genes involved in defense response to bacteria, biological adhesion, cell adhesion, killing of cells of another organism and cell division. Genetic association of the DEGs with human cardiovascular diseases suggested excessive heart problems of the ascitic chicks. Heart is, probably, the first tissue suffering from the incompetence of small respiratory system of the AS-susceptible chickens. In other word, tissue hypoxia, that causes free radicals to concentrate in heart cells, may be the commencement of events that finally result to heart failure, suffocation and death of chicks due to the AS.
KeywordsGene expression profile Ascites RNA-seq Ascites indicator traits
We cordially acknowledge Dr. Hamid Varnaseri, director of NDJ Co, Tehran, Iran, and staffs of the Pure Broiler Breeder Lines Co., Babolkenar, Iran for their technical assistance and for providing the pedigreed chickens for the current study.
KH drafted the manuscript and carried out the field work. GHS advised the laboratory work. KH and GHS designed the work and did the statistical and bioinformatics analysis. MN supervised the work and proof read the final manuscript. All authors read and approved the final manuscript.
Compliance with ethical standards
Conflict of interest
The authors declare that there is no conflict of interest.
- 9.Al-Masri F, Hassanzadeh M (2010) Anatomical parameters of cardiopulmonary system, venous blood pCO2 and pO2 tensions and the development of ascites syndrome in two genetic line chickens that are differing in their growth rate. Iran J Vet Res Shiraz Univ 11:214–221Google Scholar
- 13.Wideman RF, Eanes ML, Hamal KR, Anthony NB (2010) Pulmonary vascular pressure profiles in broilers selected for susceptibility to pulmonary hypertension syndrome: age and gender comparisons. Poult Sci 89:1815–1824. https://doi.org/10.3382/ps.2010-00754.Pulmonary CrossRefPubMedPubMedCentralGoogle Scholar
- 21.Hasanpur K, Nassiry M, Hosseini Salekdeh G et al (2016) The suitability of some blood gas and biochemical parameters as diagnostic tools or early indicators of ascites syndrome in broiler sire lines. J Anim Physiol Anim Nutr (Berl) 100:456–463. https://doi.org/10.1111/jpn.12395 CrossRefGoogle Scholar
- 22.Misztal I, Tsuruta S, Strabel T et al (2002) BLUPF90 and related programs (BGF90). Proc 7th World Congr Genet Appl to Livest Prod 28:21–22Google Scholar
- 24.Andrews S (2016) FASTQC: a quality control tool for high throughput sequence data. http://www.bioinformatics.babraham.ac.uk/projects/fastqc
- 32.Goff LA, Trapnell C, Kelley D (2014) CummeRbund: visualization and exploration of Cufflinks high-throughput sequencing data. R Packag Version 22Google Scholar
- 44.Burks JR, Rhoads DD (2011) Sequence analysis of the angiotensin II type 1 receptor (AGTR1) gene for mutations contributing to pulmonary hypertension in the chicken (Gallus gallus). Inquiry 12:49–56Google Scholar
- 48.Gray GR, Maxwell DP, Villarimo AR, McIntosh L (2004) Mitochondria/nuclear signaling of alternative oxidase gene expression occurs through distinct pathways involving organic acids and reactive oxygen species. Plant Cell Rep 23:497–503. https://doi.org/10.1007/s00299-004-0848-1 CrossRefPubMedGoogle Scholar
- 50.Fathi M, Nazer Adl K, Ebrahim Nezhad Y et al (2011) The role of oxidative stress in the development of congestive heart failure (CHF) in broilers with pulmonary hypertension syndrome (PHS). J Cell Anim Biol 5:176–181Google Scholar