Factors influencing compensatory feeding during parenteral nutrition in rats.

During parenteral nutrition (PN) there is an incomplete compensatory decrease in oral caloric intake. The effects of two factors influencing nutrient utilization, diurnal timing of PN infusion and composition of available diet, on compensatory feeding were investigated in male rats receiving 100% of daily caloric need as PN (PN-100). Compensation for infused calories increased from 70 to 80% (P < 0.05) when the timing of infused kilocalories more closely matched diurnal pattern of oral kilocalories intake (e.g., 75% kcal daily during the dark phase, 25% during the light phase). There was a similar degree of compensation when the diet and PN-100 had the same caloric distribution (50% kcal from carbohydrate, 30% from fat, and 20% from protein). Adjusting the diurnal timing of infused calories and diet composition concurrently further increased compensation for infused calories from 70 to 90% (P < 0.05). In the rat PN-100 model, compensation for infused calories is improved by adjusting the temporal pattern of infusions and diet composition.