Abstract

Chicken performance traits are affected by the chicken growth hormone (cGH) gene due to its essential part in metabolism and growth, and genetic polymorphisms may be useful as a genetic marker for growth traits. However, no comprehensive review provides information on the cGH polymorphisms and their correlation with egg production traits. The study systematically reviewed the single nucleotide polymorphisms (SNPs) of the growth hormone gene and their association with the chicken’s egg production traits. Four databases, Google Scholar, ScienceDirect, PubMed, and Web of Science, were used to search the literature where the keywords ‘growth hormone, single nucleotide polymorphisms, genetic variations, genetic effects, egg production traits, and chickens were the keywords during the literature search. The outcomes revealed that four articles published in 2013, 2014, 2015, and 2018 were included. The results indicated that four SNPs (T185G, G662A, T3094C, and C3199T) were identified, with allelic frequencies ranging from 0.020 to 0.964 and genotypic frequencies ranging from 0.007 to 0.930. The findings indicated that some of the articles used more than one breed. The present reveiw revealed that egg number was found to be significantly associated with discovered genotypes six times, while body weight at first egg and egg weight at first egg were found to be significantly related to discovered genotypes four times. However, additional research is required to validate the identified SNPs. Furthermore, identified SNPs could serve as possible molecular markers to genetically improve egg production in chickens.