Maternal GH/HaeIII Polymorphism Links Placental Efficiency to Postnatal Growth in Indigenous Awassi Lambs

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Dağdelen Türkyilmaz Ü., Türkyilmaz D.

X. International Congress on Domestic Animal Breeding, Genetics and Husbandry, Muğla, Türkiye, 22 - 24 Eylül 2026, ss.245-256, (Tam Metin Bildiri)

  • Yayın Türü: Bildiri / Tam Metin Bildiri
  • Basıldığı Şehir: Muğla
  • Basıldığı Ülke: Türkiye
  • Sayfa Sayıları: ss.245-256
  • Atatürk Üniversitesi Adresli: Evet

Özet

This study aimed to determine growth hormone (GH) gene polymorphism in indigenous Awassi ewes and to evaluate its associations with the postnatal growth performance and placental characteristics of their lambs. The study was conducted in 2022 using 45 Awassi ewes aged 2, 3, and 4 years and their singleton lambs. The experimental population included 15 lambs born to 2-year-old ewes, 12 lambs born to 3-year-old ewes, and 18 lambs born to 4-year-old ewes. Of the lambs, 21 were female and 24 were male. Maternal GH exon 5 polymorphism was determined using the polymerase chain reaction–restriction fragment length polymorphism method with the HaeIII restriction enzyme. Three genotypes, LL, LV, and VV, were identified at frequencies of 46.67%, 40.00%, and 13.33%, respectively. The frequencies of the L and V alleles were 0.667 and 0.333, and the genotype distribution did not deviate from Hardy–Weinberg equilibrium (p>0.05).

Maternal GH genotype was not significantly associated with lamb birth weight or placental weight (p>0.05). However, lambs born to LV ewes had higher weaning weights (16.28±0.42 kg) than those born to LL (15.11±0.38 kg) and VV (14.76±0.67 kg) ewes (p<0.05). Average daily gain was also higher in lambs from LV ewes (0.198±0.007 kg/day) compared with lambs from LL (0.179±0.006 kg/day) and VV (0.173±0.011 kg/day) ewes (p<0.05). Placental area differed among maternal genotypes, with the highest value observed in LV ewes (2318.6±126.4 cm²; p<0.05). Placental efficiency was also higher in the LV group than in the LL and VV groups (p<0.05). Maternal age significantly affected placental area and lamb birth weight (p<0.05), while male lambs were heavier at birth than female lambs (p<0.05).

The results indicated that maternal GH/HaeIII polymorphism was associated with variation in postnatal growth and selected placental characteristics in Awassi sheep. In particular, the LV maternal genotype was associated with higher weaning weight, average daily gain, placental area, and placental efficiency. These findings suggest that maternal GH gene polymorphism may contribute to the genetic and physiological regulation of offspring growth; however, validation in larger Awassi populations is required before its use in marker-assisted selection programmes.