Differential growth, Cardiovascular risk, and Polymorphism in Targeted Regions of Ryanodine Receptor 2 (RYR2) gene in Three Breeds of Chickens.

Sudden death syndrome (SDS) is a stress-related genetic disease in broilers with no diagnostic clinical or necropsy finding. SDS is often preceded by elevated markers of cardiovascular risks (Obesity, Blood glucose, Lipidemia and Inflammation) in broilers. Mutation of Ryanodine Receptor 2 (RYR2) gene, which controls rapid release of ca ²⁺ from the sarcoplasmic reticulum (SR) into the Cystol during muscle contraction has been associated with sudden death syndrome in broilers, but there are no reports on the genetic association between RYR2 mutation and cardiovascular risk markers in broiler. This study aims to investigate the role of RYR2 mutation in the development of SDS using the linkage association approach. The study compares exotic broiler chicken (Ross 308, Arbor Acres) with the less susceptible indigenous Noiler chicken breed as a contrast to identifying genetic markers linked to SDS susceptibility. Key findings revealed a Single Nucleotide Polymorphism (SNP) near a functional RYR2 region at chicken genome location 3:36968262. The Noiler and Arbor Acres breeds carried an A (Adenosine) allele, while Ross 308 carried a G (Guanine) allele, with the G allele associated with increased cardiovascular risk and stress. Moreover, Arbor Acres and Ross 308 breeds exhibited higher stress levels and cardiovascular risk than the Noiler breed using certain metrics of measurement. These results underscore the critical role of RYR2 genetic differences in growth and cardiovascular traits in poultry, these findings suggest that genetic differences in the RYR2 gene play a crucial role in growth and cardiovascular traits in poultry, offering valuable insights for breeding programs.