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Nutrient Metabolism - Chronic, But Not Acute Energy Restriction Increases Intestinal Nutrient Transport in Mice
Ronaldo P. Ferraris,2 Qing-Xue Cao and Shyam Prabhakaram

• ABSTRACT
  Chronic energy restriction (ER) dramatically enhances intestinal absorption of nutrients by aged mice.
  Do adaptations in nutrient absorption develop only after extended ER or immediately after its initiation? To
  determine the time course of adaptations, we measured rates of intestinal glucose, fructose and proline transport
  1–270 d after initiation of ER (70% of ad libitum) in 3-mo old mice. Mice of the same age that consumed food ad
  libitum (AL) served as controls; a third group was starved for 1 or 2 d only, to distinguish the effects of acute ER
  from those of starvation. Acute ER of 1, 2 and 10 d had no effect on nutrient absorption. Starvation significantly
  decreased intestinal mass per centimeter, thereby reducing transport per centimeter and intestinal absorptive
  capacity without significantly altering transport per milligram of intestine. ER for 24 d enhanced only fructose
  uptake, whereas ER for 270 d enhanced uptake of all nutrients by 20–100%. Despite marked differences in body
  weights, the wet weights of the stomach, small intestine, cecum and large intestine were generally similar in AL and
  ER mice, suggesting that the gastrointestinal tract was spared during ER. In contrast, the wet weights of the lungs,
  kidneys, spleen, heart, pancreas and liver each differed by 40–120% between ER and AL mice. Intestinal transport
  adaptations develop gradually during ER, and the main mechanism underlying these adaptations is a dramatic
  increase in transport activity per milligram tissue. J. Nutr. 131: 779–786, 2001.

Developmental reprogramming of rat GLUT-5 requires de novo mRNA and protein synthesis; Lan Jiang, Ronaldo P. Ferraris

Effect of dietary phosphorus and vitamin D3 on phosphorus levels in effluent from the experimental culture of rainbow trout (Oncorhynchus mykiss); R.M. Coloso, S.P. Basantes, K. King, M.A. Hendrix, J.W. Fletcher, P. Weis, R.P. Ferraris

• ABSTRACT
  Excessive phosphorus P levels in aquaculture effluents violate federally mandated limits and pose a serious threat to the freshwater environment. In rainbow trout culture, effluent P probably originates as fecal and metabolic waste product because assimilation of dietary P is relatively low. We therefore decreased dietary P and increased dietary vitamin D3 levels, methods that enhance P assimilation in mammals, in purified and semi-purified trout diets, then monitored effluent P. Soluble effluent P reached a peak right after feeding and returned to baseline levels in between feeding times. The peak and average concentrations of soluble P in the effluent were mainly influenced by dietary P. Average P in fecal dry matter also decreased with dietary P. Neither dietary P nor vitamin D under the conditions of the experiment had significant effects on whole body P content but P deposition as a percentage of P intake decreased with increased dietary P. The dietary combination of low P and high vitamin D decreased soluble and fecal P levels in the effluent indicating a strategy whereby effluent P concentrations can be reduced by regulation of P metabolism. ©2001 Published by Elsevier Science B.V.

Intestinal Perfusion Induces Rapid Activation of Immediate Early Genes in Weaning Rats; Lan Jiang, Heather Lawsky, Relicardo M. Coloso, Mary A. Dudley, and Ronaldo P. Ferraris

Intestinal Transport During Fasting; Ronaldo P. Ferraris, Hannah V. Carey

• ABSTRACT
  Fasting or malnutrition (FM) has dramatic effects on small intestinal mucosal structure and transport function. Intestinal secretion of ions and fluid is increased by FM both under basal conditions and in response to secretory agonists. Intestinal permeability to ions and macromolecules may also be elevated by FM, which increases the potential for fluid and electrolyte losses and for anaphylactic responses to luminal antigens. Mucosal atrophy induced by FM reduces total intestinal absorption of nutrients, but nutrient absorption normalized to mucosal mass may actually be enhanced by a variety of mechanisms, including increased transporter gene expression, electrochemical gradients, and ratio of mature to immature cells. These observations underscore the value of enteral feeding during health and disease.