Ontogeny of Taurocholate Accumulation in the Terminal Ileal Mucosal Cells of Young Chicks

The everted, ileal ring technique of Little and Lester was utilized to study taurocholate accumulation against a concentration gradient in the terminal ileal mucosal cells of chicks from hatch to 6 wk of age. The chicks had low levels of taurocholate accumulation at hatch. A three- to fourfold increase in accumulation was observed at Day 3 posthatch, but taurocholate returned to baseline levels within 2 days. This peak has not been previously reported in any other species. The age-related peak in the ileal accumulation of taurocholate was not influenced by removal of the yolk sac at hatch, oral feeding of yolk, or supplementation of the diet with taurocholate or cholestyramine. Comparison of ileal uptake of proline versus uptake of taurocholate during the 1st wk posthatch indicated that the peak in ileal taurocholate accumulation is not the result of a general increase in absorptive capacity through cell proliferation. These data suggest that the age-related changes in taurocholate absorption are genetically determined and are not responsive to external influences.