Modification by diet and environmental temperature of enterocyte function in piglet intestine.

Abstract

SUMMARY1. Intestinal morphology, enterocyte life span and alanine transport have been studied in the small intestine of piglets fed different amounts of food at high and low environmental temperatures.2. Villus height and crypt depth were both greater in pigs maintained on a high energy intake. Environmental temperature produced negligible effects on intestinal structure.3. Enterocyte life span increased from 45 h in pigs kept at 35 0C to about 70 h in animals living at 10 'C. A low energy intake prolonged enterocyte life span at an environmental temperature of 10 'C.4. The Na-dependent fraction of alanine uptake, judged by analysis of autoradiographs and by measurement of alanine-dependent short-circuit current, was greater in intestines taken from pigs maintained on a restricted diet. This effect, which appeared to be due to changes in the number of carriers (Jm) rather than the apparent affinity of the carrier for the amino acid (Ki), was most noticeable using intestines taken from pigs kept at 10 'C.5. The Na-independent fraction of alanine uptake remained unchanged either by alterations in diet or in the environmental temperature at which pigs were kept.6. Restricting the diet of pigs at low environmental temperature leads to a relative increase in the capacity of the intestine to absorb alanine through an Na-dependent process. This increase appears to be caused by an extension of enterocyte life span rather than by any change in the time of onset or rate of expression of carrier function in a single enterocyte.

Dexamethasone selectively increases sodium‐dependent alanine transport across neonatal piglet intestine.

“…A similar induction of system A type transport has already been reported for older pigs maintained on a restricted diet (Dauncey et al 1983). Present results with dexamethasone, however, obtained under conditions where food intake was apparently normal, suggest that steroid hormones might have a particularly important part to play in regulating this type of transport in the young animal.…”

“…In this work alanine transport was found to take place through both sodium-dependent and sodium-independent routes (Dauncey, Ingram, James & Smith, 1983;Smith, 1984;Miller, James, Smith & Bourne, 1986), the former being enhanced by maintaining piglets at a low environmental temperature on a reduced food intake (Dauncey et al 1983). Similar effects on sodium-dependent amino acid transport by different cell types have been obtained in vitro through addition of hormones or removal of system A amino acids from the culture medium (Shotwell, Kilberg & Oxender, 1983).…”

Postnatal growth of gut and muscle: competitors or collaborators

“…In this sense alone, the gastrointestinal tract grows continuously throughout the postnatal life of the organism. In weaned rodents, sheep and pigs the daily rate of cell migration and loss is approximately 25% of the population of villus enterocytes (Dauncey et al 1983;Southon et al 1985;Attaix & Meslin, 1991), so that one-quarter of protein synthesis in the mucosa (and to some extent in the serosa; see Goldspink et al 1984) is devoted to the production of new cells.…”

Alteration of Lactase and Aminopeptidase N Expression in Porcine Enterocytes by Energy Intake and Environment

“…Young pigs kept in the cold maintain enterocytes on the villus for about 5000 more time than their litter-mates in the warm (Dauncey, Ingram, James & Smith, 1983). It might therefore be expected that they would also be more sensitive to thyroid hormones.…”