Abstract
The aim of the study was to analyse the effects of maternal obesity and the litter size on the growth rate and plasma concentrations of GH, IGF-1, insulin, and glucose in ewe lambs during the first 6 weeks of their postnatal life. Seventy-six SCP sheep: 35 ewes and 41 female offspring were used. Before gestation, the ewes were divided into two groups: N - normally weighing and O - obese sheep. After the parturition, the lambing rate and the birth type were estimated. The born female lambs were separated into five groups: IN - singleton and IIN - twin offspring of normally weighing mothers; IO - singleton, IIO - twin and IIIO - triplet offspring of obese mothers. They were weighed at birth and weekly thereafter, until the completion of the 6th week of their postnatal life. Afterward, daily weight gains and concentrations of biochemical parameters were analysed. No significant differences in GH, IGF-1, insulin, and glucose levels between the groups of lambs born to non-obese and obese sheep, both carrying singletons and twins, were found. In contrast, significantly increased concentrations of GH (P≤0.001), insulin (P≤0.001), and glucose (P≤0.05) and markedly dropped level of IGF-1 (P≤0.001), as well as reduced daily body mass gains in triplets in comparison to other groups of lambs were observed. Maternal obesity caused significant lambing rate’s accretion with the rise in triplets’ frequency. However, in ewe lambs of this birth type, the disrupted relationships between plasma levels of GH, IGF-1 and growth rate, and between plasma levels of insulin and glucose were found.