Abstract: Methods: The sequence amplification and 3＇race of chicken SSTR2 was conducted by reverse transcription PCR (RT-PCR) and RACE; The ontogenetic expression of SSTR2 mRNA in colorectum of Arbor Acre (AA) chicken and yellow–feathered chicken was studied by relative quantitative RT-PCR. Results: The length of chicken SSTR2 mRNA was 2311bp from ATG to Poly (A) and the nucleotide sequence in ORF of AA chicken was completely same with that of electronic clone; the sequence homology was 81.0% and 79.5% identical with that of human and rat, respectively. The protein translated by the nucleotide sequence in the ORF composed by 371 amino acids while the protein of human and rat were composed by 369 amino acids. Comparison with the chicken SSTR2 amino acid sequence revealed 87.1% and 86.3% identity with human and rat, respectively. The SSTR2 mRNA expression abundance of AA chicken on 30d was significantly higher than that on other time points (P＜0.05) while the expression abundance had no significant difference on 2d, 16d, 44d and 58d (P＞0.05). The SSTR2 mRNA expression level of yellow-feathered chicken on 16d was significantly higher than that on 30d, 44d and 58d (P＜0.05) and there was no difference between 2d, 30d, 44d and 58d (P＞0.05). SSTR2 mRNA abundance of AA chicken was significantly higher than that of yellow-feathered chicken on 30d, 44d and 58d (P＜0.05). Conclusions: These results indicate that the homology of SSTR2 is high between species; AA chicken has the different ontogenetic expression of SSTR2 mRNA with the yellow-feathered chicken in colerectum and the expression abundance of AA chicken is significant higher than that of yellow-feathered chicken during the anaphase of growth.

Key words: Broiler chicken, Colorectum, SSTR2, Molecular cloning, Ontogenetic expression