Effect of Growth Hormone Exon-5 Polymorphism on Growth Traits, Body Measurements, Slaughter and Carcass Characteristics, and Meat Quality in Meat-Type Lambs in Turkey

This study examined the relationship between GHE5 polymorphisms and growth and carcass characteristics of meat-type sheep breeds reared in Turkey. A total of 202 lambs were tested, consisting of five breeds. By SSCP analysis and nucleotide sequencing, 14 nucleotide changes (12 substitutions and two deletions) were identified in four variants of GHE5. In the coding region of GHE5, five substitutions occur, including c.1588C>Y(C/T) (Ala160Val), c.1603A>M(A/C), c.1604G>S(G/C) (Lys165Thr), c.1606A>W(A/T) (Gln166Leu), and c.1664C>Y(C/T). P3 female and P1 male lambs had the highest rump height at weaning, whereas P3 females and P2 males had the highest chest depth (p < 0.05). At yearling, P1 variant lambs have longer body length (BL; p < 0.05), wider leg circumferences, and thinner cannon bone perimeter (CBP) (p > 0.01), in contrast to P2 variant lambs, which have a shorter BL and thicker CBP. Furthermore, P2 had a greater percentage of neck, shoulder, and leg, P1 had a greater percentage of loin, and P3 had a greater percentage of rack, but there was no significant difference between them. A marker-assisted selection approach can be used to improve sheep carcass quality traits by taking advantage of the nucleotide substitutions found on GHE5 and the detected differences between variants.