Restricted maternal nutrition and supplementation of propylene glycol, monensin sodium and rumen‐protected choline chloride during late pregnancy does not affect muscle fibre characteristics of offspring

BACKGROUND: Grazing in arid and semi‐arid regions faces pregnant ewes with feed restrictions and hence affects the offspring muscle fibre characteristics. Using feed additives that enhance nutrient availability during foetal muscle development is expected to alter offspring skeletal muscle characteristics. OBJECTIVES: This study evaluated the effect of maternal restricted nutrition and supplementation of propylene glycol, monensin sodium and rumen‐protected choline chloride on lamb's muscle fibre characteristics. METHODS: Forty‐eight Ghezel ewes were randomly allocated to one of six diets (N = 8) during the last 6 weeks of gestation: ad libitum feed intake (AL); restricted feeding (RF); restricted feeding containing propylene glycol (PG); restricted feeding containing propylene glycol and monensin sodium (MS); restricted feeding containing propylene glycol and rumen‐protected choline chloride (RPC); restricted feeding containing propylene glycol, monensin sodium and rumen‐protected choline chloride (PMC). The muscle samples were obtained from the semitendinosus muscle of 2‐week‐old male lambs (n = 5/treatment) via biopsy and were stained and classified as fibre types I, IIA and IIB. RESULTS: Pre‐parturient maternal feed restriction and administration of propylene glycol, monensin sodium and rumen‐protected choline chloride had no significant effect on fibre‐type composition, fibre density of muscle, muscle cross‐sectional area and volume density of fibres (p > 0.05). CONCLUSIONS: Either maternal dietary restriction or supplementation of nutrient flux–involved additives during late pregnancy did not alter muscle fibre development and had no short‐term effects on muscle properties of the resulting offspring as myogenesis occurs in early and mid‐gestation, not late gestation. Therefore, maternal nutrition may not be a problematic issue in sheep production in arid and semi‐arid areas.