Author
Fetterer, Raymond | |
Miska, Kate | |
Jenkins, Mark | |
WONG, ERIC - Virginia Tech |
Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 10/1/2014 Publication Date: 10/1/2014 Citation: Fetterer, R.H., Miska, K.B., Jenkins, M.C., Wong, E. 2014. Expression of nutrient transporters in duodenum, jejunum and ileum of Eimeria maxima- infected broiler chickens. Avian Diseases. 113(10):3891-4. Interpretive Summary: Poultry coccidiosis is caused by several different species of an intestinal protozoan parasite which causes considerable annual losses to the poultry industry. Among the species causing coccidiosis, a species which infects the middle regions of the intestine is often considered the most important. The primary impact of infection on the chicken is reduced growth and decreased feed efficiency. This growth reduction may result from changes in expression of genes regulating digestive enzymes and nutrient transporter molecules on membranes of cells located on the absorptive surface of the intestine. The objective of the study was to determine the expression of these genes in the intestinal tract of infected broiler chickens. The results indicate that the expression of most of the genes studied was changed in the middle region of the intestine that is the major site for infection by the parasite. In addition, expression of genes regulating transport function in other regions of the intestine is also altered. This result may be due to spread of the infection from its normal site to other regions of the gut or to a more general host response to the infection. This result also indicates that expression of nutrient transporters is altered following infection of broiler chicks with coccidia. Technical Abstract: The intracellular parasite, Eimeria maxima, invades epithelial cells of the intestine causing malabsorption, diarrhea, and decreased feed conversion resulting in significant economic losses to poultry producers. The uptake of amino acids is mediated by active transporters located on the basal and brush border membranes of intestinal epithelial cells. The current study investigated the expression of amino acid transporters (AAT) in the intestine of chicks infected with Eimeria maxima. Tissue from each intestinal segment (duodenum, jejunum and ileum) was taken from birds euthanized at 7 days post infection with 3 x 103 oocysts/ bird and processed to recover RNA. Analysis of gene expression was performed using real time qRT-PCR. Results were given as relative expression using '2-microglobulin as an endogenous control. All the AAT genes studied were expressed in three segments of the intestines and expression of the genes was altered by infection with E. maxima. However, there was no difference in gene expression between intestinal segments from infected birds even though the jejunum is considered the parasite’s primary predilection site. The results also demonstrate that transporters associated with brush border membranes were down- regulated while transporters associated with the basolateral membranes were up- regulated. The results suggest that E .maxima alters the expression of AATthroughout the small intestine. Further, the egress of intracellular stores of amino acids through the basolateral surface, and failure of entry of amino acids through the brush border surface, would result in a cell that is deprived of energy. This action may contribute to eventual death of the cell and thus limit E. maxima proliferation. |