Investigation of effects of GDF-8, GH and FABP4 gene variations on meat yield and quality in some sheep breeds

In this dissertation, the variation of GDF-8 (Growth and Differentiation Factor-8), GH (Growth Hormone), and FABP4 (Fatty Acid Binding Protein-4) genes in Kıvırcık, Karacabey Merino, Bandırma, Hampshire x Merino and Ramlıç breeds and their effects on growth characteristics, meat yield and quality were investigated. A total of 230 lambs were used as research material. Four nucleotide changes in the 3'UTR region of the GDF-8 gene; 7 nucleotide and 3 amino acid changes in GH Exon-4 region; 2 deletions, 12 nucleotides, and 3 amino acids changes in the GH Exon-5 region; 13 nucleotide and 4 amino acid changes in the FABP4 Exon-2-Intron-2 region; 8 nucleotide and 2 amino acid changes in FABP4 Exon-3-Intron-3 region were determined. The effects of GH Exon-4 and Exon-5 and FABP4 Exon-2 and Exon-3 polymorphisms on some body measurements were significant (p<0.05). The effects of GDF-8, GH Exon-4 and Exon-5, and FABP4 Exon-3 polymorphisms on some ultrasonographic MLD measurements were significant (p<0.05). The effects of GDF-8, GH Exon-4, and FABP4 Exon-2 and Exon-3 polymorphisms on some carcass slaughter characteristics were found to be significant (p<0.05). It was found that GH Exon-4 and Exon-5 polymorphisms had a significant effect on some meat color parameters (p<0.05). The effect of FABP4 Exon-3 polymorphism on texture profiles (hardness and elasticity) was found to be significant (p<0.05). According to obtained results, it is expected that these gene regions will shine new light on further studies which aim to improve carcass and meat quality. It is recommended that the genetic factors affecting the yield characteristics be used in further marker-assisted selection schemes.