Age-Dependent Variation of Telomere Length and DNA Damage in Chicken

Birds are unique models for molecular studies on aging processes and cellular senescence because of their slow rates of aging and comparatively long life spans among homoeothermic animals. The study aimed to examine the relative telomere length and amount of nuclear, mitochondrial DNA lesions in hens of different ages and to find out the correlation between these biomarkers of aging. The study was carried out on hens of crossbreed «High Sex Brown» of different age groups - 1, 75, 225, 330, 450 days old. The measurements of telomeres and DNA damage were done in red cells of hens using quantitative PCR technique. We found out that the amount of telomeric DNA reduced significantly with age. Telomere length ratio to control group (1 day old) made up: 0.88±0.08 for 75 days old, 0.73±0.07 for 225 days old, 0.66±0.1 for 330-days old and 0.58±0.12 for 450 days old. The amount of DNA lesions in both genomes had great, age-dependent increase. The relative quantity of lesions per 10 kb detected in the nuclear DNA were as follows: 0.17±0.19 for 75 days old, 0.66±0.21 for 225 days old, 1.02±0.33 for 330-days old and 1.48±0.45 for 450 days old and the relative quantity of lesions in mtDNA were as follows: 0.11±0.06 for 75 days old, 0.84±0.23 for 225 days old, 1.18±0.3 for 330-days old and 1.49±0.35 for 450 days old. The results obtained are of fundamental interest for aging processes, as well as could have an economic value for poultry farming.