Development of swine adipose tissue: morphology and chemical composition

Differentiation and growth of swine subcutaneous adipose tissue was assessed by chemical analysis of tissue components, cell size measurements of isolated adipocytes, and light and electron microscopic observations. At birth all adipocytes were multilocular (contained multiple small lipid droplets), but by day 3 postpartum, many were already differentiated to the unilocular state (one major, central lipid droplet). Microscopic observations of fixed tissue, cell size determinations on isolated adipocytes, and chemical analysis of tissue composition indicated a marked increase in adipocyte size accompanied by an increase in the size of the central lipid droplet with age. Small cells were observed at all ages (in both fixed tissue and isolated cell preparations), yielding biphasic size distributions. Although the adipocyte stem cell was not discerned, an early stage in differentiation, designated an adipoblast, was observed.