Retarded myelination in the lumbar spinal cord of piglets born with spread-leg syndrome

Piglets born with spread-leg syndrome, a congenital weakness of the hindlim b adductors, were investigated to determine the site of lesion leading to l imb impairment. Histological and immunohistochemical studies of the motor n euron unit showed no alterations but quantitative analysis revealed a reduc tion of axonal diameter and myelin sheath-thickness of the fibres innervati ng: the adductors of the affected limbs. In the lumbar spinal cord a lack o f myelination was observed in the tracts descending to the lower motor neur ons. Recovery from the syndrome was accompanied by a catching-up of myelina tion with that of the controls. The spread-leg syndrome is due to a nutriti onal deficiency in the sow; thus it is assumed that the deficient maternal substances, mainly choline and methionine. are essential for the normal mye lin production by spinal white matter oligodendrocytes of the fetus.