Long-term effects on adiposity after preweaning nutritional manipulations in the gastrostomy-reared rat

Male Long-Evans rat pups were either fed by continuous intragastric infusion of a milk formula to match the growth rate of their normally reared siblings, or overfed by continuous infusion of a fat-supplemented formula from d 4 through d 18 postpartum. The early overfeeding accelerated growth and the overfed rats remained significantly heavier than normally reared siblings as adults. Early overfeeding with this procedure led to an adult obesity at 14 mo characterized by significantly larger epididymal and retroperitoneal fat depots resulting from an increase of both fat cell size and number, and by an increase in adipose tissue lipoprotein lipase activity. Gastrostomy rearing per se, without overfeeding, resulted in adult rats that weighed the same as normally reared siblings but had significantly larger retroperitoneal fat depots because of more adipocytes. These findings suggest that the quantity of food consumed during early growth and development, and the quality of early nutrition and/or the early rearing environment affect adipose tissue development and have long-term consequences that persist in the rat.