|SU, SHENGCHEN - Virginia Tech|
|LAMONT, SUSN - Iowa State University|
|WONG, ERIC - Virginia Tech|
Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/10/2018
Publication Date: 12/1/2018
Citation: Miska, K.B., Fetterer, R.H., Su, S., Jenkins, M.C., Lamont, S., Wong, E. 2018. Differential expression of intestinal nutrient transporters and host defense peptides in E. maxima infected Fayoumi and Ross chickens. Poultry Science. 97:4392-4400.
Interpretive Summary: Coccidiosis is responsible for causing large economic losses to the poultry industry worldwide. This disease is caused by a single cell parasite Eimeria. Several species of Eimeria are responsible for causing coccidiosis. Eimeria infect gut epithelial cells that line the inside of the intestine and different species of Eimeria are partial to infection of specific portions of the gut. At the height of infection, the parasites cause damage to the intestine, resulting in loss of appetite, decrease in weight gain, increase in feed conversion, diarrhea, and sometimes death. The goal of the present study was to determine whether different strains of chickens can be more resistant to Eimeria infection. The study utilized two breeds of chickens, one was a typical breed used for meat (Ross), and the other an Egyptian breed (Fayoumi)that is thought to be more hardy than the typical modern meat chicken. The study found that an experimental Eimeria infection in both strains of birds resulted in similar losses in the ability to gain weight. Therefore, from the production standpoint, no differences were found between the different strains of birds used. At the molecular level, the Fayoumi chickens had higher basal levels of expression genes that encode molecules involved in destroying pathogens (defensins). The expression of nutrient transporters was affected across all birds tested. Downregulation of nutrient transporters involved in bringing nutrients from the lumen of intestine was demonstrated, suggesting that during Eimeria infection, the transport of nutrients into the gut is compromised. It has been previously thought that slower growing heritage breeds like the Fayoumi chickens may be resistant to Eimeria, however the present study shows that these animals are readily affected by the infection.
Technical Abstract: Fayoumi chickens originated in Egypt and are believed to be more disease resistant compared to commercial broiler chickens. The objective of this study was to compare mRNA expression of intestinal nutrient transporters, digestive enzymes, and host defense peptides (HDP) between E. maxima challenged Fayoumi and Ross broiler chickens. At 21 d of age, Ross broilers and Fayoumi lines M5.1 and M15.2 were challenged with 1,000 E. maxima oocysts. Control birds were not challenged. Duodenum, jejunum and ileum were sampled (n=6) at 7 days post challenge. Gene expression was analyzed using relative quantification PCR. Data were analyzed by ANOVA and significance level was set at P'<'0.05. There was numerical, but not statistically significant, differential weight gain depression for Ross (15%) and Fayoumi lines M5.1 (21%) and M15.2 (22%) and significant line-specific changes in gene expression. For digestive enzymes and nutrient transporters, there was downregulation of aminopeptidase N, the amino acid transporters b0,+AT/rBAT, BoAT and EAAT3 in the jejunum of Ross and the two lines of Fayoumi chickens, indicating that E. maxima challenge likely caused a decrease in nutrient uptake. For the HDP, there was downregulation of avian beta defensin (AvBD) 1, 6, 10, 12, and 13 in the jejunum of the two Fayoumi lines, but no change in the Ross broilers. In the duodenum, there was upregulation of AvBD6, 11, 12, and 13 in Fayoumi line M15.2, but no change for these AvBD in Ross and Fayoumi line M5.1 chickens. Liver expressed antimicrobial peptide 2 (LEAP2) was downregulated in the duodenum and jejunum of Ross and Fayoumi line M5.1 chickens compared to Fayoumi line M15.2. The homeostatic, non-challenged levels of AvBD mRNA were greater in Fayoumi line M15.2 than Ross and Fayoumi line M5.1 in the duodenum and ileum. This study demonstrates tissue and genetic line-specific transcriptional responses to E. maxima, highlights novel potential candidate genes for response to coccidiosis, and confirms a role for several previously reported genes in response to coccidiosis.