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The small intestine of the chicken undergoes intensive changes in the immediate posthatch period, increasing in size and developing crypts, villi and mature enterocytes. During this time, chicks are also transferring from nutrition based on the lipid-rich yolk to exogenous carbohydrate-rich feeds. The cdx homeobox genes participate in axial patterning and in definition of cell identity in embryos, and some cdx genes remain active postpartum in organs such as the intestine. In this study, the transcription patterns of two of these genes, cdxA and cdxB, were examined in the small intestine of the embryo and posthatch chick; in addition, the effects on these genes of starving for 48 h at hatch were examined. Both cdx transcription factors were upregulated toward the time of hatch and were observed in proliferating enterocytes; this enhanced expression continued posthatch. Distribution of cdxA changed with age and was found at higher concentrations in mature enterocytes. Starving from 0 to 48 h posthatch retarded growth and decreased enterocyte proliferation and expression of cdxA and cdxB. After access to feed, expression of cdx genes was enhanced. Chicken homeobox genes cdxA and cdxB are expressed in all enterocytes during embryonic and posthatch development; however, cdxA may have a role in enterocyte maturation posthatch. CdxB was expressed later in development then previously reported. [ABSTRACT FROM AUTHOR]

A 970 bp cDNA Na(+)/glucose cotransporter (SGLT1) was isolated and sequenced from chicken jejunum by reverse transcriptase polymerase chain reaction (RT-PCR) using primers based on conserved regions. Using the 970 bp PCR product as a specific probe, Northern Blot hybridization indicated a transcript of ca. 4 kb. The isolated chicken intestinal SGLT1 cDNA was used to quantitate mRNA expression. Glucose uptake activity and kinetics were determined in brush border membrane vesicles (BBMV) from jejunum tissue of chickens which were either fed, food-deprived or refed following food deprivation. Net glucose uptake to BBMV was higher (P: < 0.02) in the control and refed chicks (149 +/- 11.9, 139.6 +/- 7.43 pmol x mg protein(-1) x s(-1)) than in food-deprived chicks (107 +/- 4.23 pmol x mg protein(-1) x s(-1)). The k(m) (150 micromol/L) and V:max (1111.1 pmol x mg protein(-1) x s(-1)) were higher in the food-deprived chicks compared to control and refed birds (25, 24 micromol/L and 227,142 pmol x mg protein(-1) x s(-1), respectively). Expression of SGLT1 mRNA was significantly enhanced in the food-deprived and refed birds. In food-deprived chicks the lower affinity and higher activity of the SGLT1 transporter for glucose were accompanied by higher expression of mRNA which might indicate that the transporter was upregulated by low substrate concentration. Quantification of expression of intestinal mRNA of SGLT1 provides important information concerning control of nutrient uptake. [ABSTRACT FROM AUTHOR]

1. The effect of vitamin A on the small intestine was examined in vitamin-A-deficient meat-type chickens. 2. Maturation and activity of the small intestinal cells were assayed by detection of proliferating cells with proliferating cells nuclear antigen, goblet cells with Alcian blue, mature cells with alkaline phosphatase and extent of RNA expression with dot blot analysis. 3. Vitamin A deficiency caused hyperproliferation of enterocytes, a decrease in the number of goblet cells, decreased alkaline phosphatase activity and decreased expression of 2 brush-border enzymes. 4. Our findings suggest that the absence of vitamin A interferes with the normal growth rate in chickens because it influences functionality of the small intestine by altering proliferation and maturation of cells in the small intestinal mucosa. [ABSTRACT FROM AUTHOR]