Location: Livestock Behavior ResearchTitle: Zinc’s impact on intestinal barrier function and zinc trafficking during coccidial caccine challenge Author
Submitted to: Poultry Science
Publication Type: Abstract Only
Publication Acceptance Date: 6/2/2012
Publication Date: 7/9/2012
Citation: Troche, C., Eicher, S.D., Applegate, T.J. 2012. Zinc’s impact on intestinal barrier function and zinc trafficking during coccidial caccine challenge. Poultry Science. 91(E-suppl.1):145. Interpretive Summary:
Technical Abstract: In order to evaluate the effects of Zn supplementation on intestinal barrier function and Zn trafficking, three dietary regimens were formulated: a basal corn/SBM diet formulated with a Zn-free vitamin/mineral premix (Basal), and two Zn regimens formulated to provide 90 mg/kg total dietary Zn from either ZnSO4, or a 1:1 blend of ZnSO4 and a Zn-amino acid complex (AvailaZn100; Blend. Additional concentrations of 45 and 70 mg/kg were created by blending the 90 mg/kg Zn and basal regimens. An oral gavage of a coccidial vaccine was administered weekly at 10 times the recommended dosage (10XCV) to half of the birds (6 replicate cages per diet and challenge status; 6 chicks/cage). Ussing chambers were used to study the effect of dietary regimen and 10XCV on the jejunal secretory response, measured by short circuit current (delta ISC). Response to carbachol (a drug which induces Cl- secretion, mimicking the anaphylactic response and increasing ISC) was 50 fold higher with 10XCV. This pattern of increased delta ISC with 10XCV was reversed with the Zn Blend regimen having a delta ISC response which was equivalent to tissues from unchallenged birds (P = 0.03). Zinc regimens, particularly the Zn Blend, improved the anaphylactic response of 10XCV sensitized tissues. As measured through flow cytometry, exposure to 10XCV depressed intracellular free Zn (IFZ) by 27% and increased phagocytic capacity by 5% (P = 0.0001). Zinc trafficking was measured through mRNA expression of Zn efflux (ZnT5, 7) and influx (ZIP9, 13) transporters in cecal tonsil mucosa. The ratio of ZIP:ZnT cecal expression increased 13 fold with 10XCV, shifting expression towards cytosolic Zn influx (P = 0.0001). Decreased IFZ, coupled with Zn influx into the cytosol, suggests that with 10XCV, the cell shuttles Zn to cytosolic proteins. Supplemental Zn Blend prevented carbachol-induced Cl- secretion in 10XCV birds, suggesting that Zn regimens lessen the intestinal anaphylactic response of birds exposed to coccidia. Coccidial vaccine exposure significantly impacted phagocytic response and intracellular Zn trafficking within cecal tonsils.