| Publication Type: | Journal Article |
| Year of Publication: | 1992 |
| Authors: | Obst, BS, Diamond, J |
| Journal: | The Auk |
| Volume: | 109 |
| Issue: | 3 |
| Date Published: | 1992 |
| ISBN Number: | 00048038 |
| Keywords: | Gallus, Gallus gallus, Phasianidae |
| Abstract: | We measured intestinal (brush-border) uptake of the sugars glucose and fructose, and of the amino acid proline, each week from one day posthatching to 12 weeks of age in a rapidly growing strain of domestic chicken (Gallus gallus, White Cornish × Rock). Small-intestine mass increased as the 0.74 power of body mass, the same power as resting metabolic rate of the whole bird. Even on a constant diet, nutrient uptake varied with age, according to ontogenetic patterns that differed among nutrients. From the beginning to end of the 12-week period, glucose uptake per milligram of intestinal tissue remained on the average approximately constant, fructose uptake increased in the distal intestine, and proline uptake per milligram declined across all intestinal regions. Uptake capacity integrated over the whole length of the intestine generally increased for all three solutes, mostly as a consequence of increases in intestinal mass. A steep, brief, many-fold increase in glucose uptake appeared in two-week-old chicks, coinciding with increasing thermal independence and the exhaustion of yolk reserves. A similarly steep, brief, many-fold increase in proline uptake at week 6 coincided with the onset of molt and high relative growth rates. Comparisons of integrated nutrient-uptake capacities with estimated nutrient intakes suggest that intestinal nutrient uptake capacity is closely matched to dietary nutrient intake during growth. This supports the hypothesis that the intestine's capacity to assimilate nutrients may pose a proximal constraint on the rate of growth in precocial species. |
| URL: | http://www.jstor.org/stable/4088360 |
| Short Title: | The Auk |
Taxonomic name: