The chick derives its nutrients from the yolk during embryogenesis and feed in the intestine post-hatch. Both the yolk sac and the intestinal villi contain absorptive cells that mediate the uptake of nutrients. These absorptive cells contain membrane bound transporter proteins that mediate the uptake of nutrients such as amino acids, peptides and sugars and play an essential role in regulating both embryonic and post-hatch growth. We have profiled the mRNA expression of these nutrient transporters in the yolk sac during embryogenesis and in different segments of the small intestine during late embryogenesis and early post-hatch. We have found that there are tissue- and age-specific changes in nutrient transporter mRNA expression.
The host defense peptides are part of the innate immune system. In chickens, the host defense peptides include the avian beta defensins, cathelicidins and liver expressed antimicrobial peptide 2 (LEAP2). We have profiled the expression of the avian beta defensins and LEAP2 in the yolk sac and small intestine at different ages. We have shown that the epithelial cells lining the intestinal villi expressed LEAP2 mRNA
We have also profiled nutrient transporter and host defense peptide expression in response to challenge by an intestinal pathogen such as Eimeria, Salmonella and Campylobacter. In Eimeria challenged chickens, there was downregulation of nutrient transporters at both the brushborder and the basolateral membrane. In addition, there was downregulation of LEAP2 mRNA, which may promote survival of Eimeria.
The yolk sac and small intestine contain absorptive cells and other differentiated cells that arise from a population of stem cells. We are using in situ hybridization with cell-specific marker genes to identify absorptive and stem cells in both the yolk sac and small intestine. Epithelial cells lining both the yolk sac and intestinal villi express mRNA for the peptide transporter PepT1, which serves as a marker for absorptive cells. In the intestine, cells in the intestinal crypts express olfactomedin 4 (Olfm4) and Leucine-rich repeat G protein-coupled receptor 5 (Lgr5) mRNA, which are markers for stem cells. In the yolk sac, cells that express Lgr5 but not Olfm4 were localized to the vascular endothelial cells lining the blood vessels and may be hematopoietic stem cells.
- ALS/Biol 2404 Biotechnology in a Global Society
- ALS 3104 Animal Breeding and Genetics
- APSC/PPWS 5044 Biotechnology in Agriculture and Society
- Postdoctoral, Biology, 1981-1986, University of Utah
- Ph.D., Biology, 1981, University of California, San Diego
- B.S., Biology, 1976, Massachusetts Institute of Technology
Article ItemEric Wong reappointed John W. Hancock Professor of Animal and Poultry Sciences , article
A member of the Virginia Tech community since 1990, Wong has an international reputation as a leader in molecular nutrition in poultry.