72 Use of aspirin to intentionally induce gastrointestinal tract barrier dysfunction in feedlot cattle

Abstract

Stress negatively effects gastrointestinal tract (GIT) barrier function, resulting in compromised animal health. The objective of this study was to evaluate the effectiveness of aspirin to intentionally induce GIT barrier dysfunction in beef cattle. In experiment 1, sixteen crossbred heifers (425 ± 8.6 kg) were enrolled in 2 experimental periods and allotted by BW to 0, 50, 100, or 200 mg/kg BW aspirin. Four heifers per treatment received the same aspirin dose during each period, which were separated by 4 wks. Heifers were fed a 49.4% corn silage, 50.6% concentrate diet. Aspirin was delivered to animals as an oral bolus. The 200 aspirin treatment was dosed as 100 mg/kg BW aspirin 36 and 24 h prior to Cr-EDTA dosing (1 L; 180 mM). The 50 and 100 aspirin treatments were dosed 24 h prior to Cr-EDTA dosing. Urine was collected every 3 h for 48 h and analyzed for Cr using atomic absorption spectrometry. Serum was collected at 0, 24, and 48 h and analyzed for lipopolysaccharide binding protein (LBP) and interleukin-6 (IL-6) using ELISA. In experiment 2, sixteen crossbred steers (576 ± 14.2 kg) fed the same diet were allotted by BW to the 0 and 200 mg/kg BW aspirin treatments (8 steers/treatment) and were slaughtered 24 h after the last dose. Jejunal tissues were collected and tight junction mRNA expression was determined. Data were analyzed using the MIXED procedure of SAS. Aspirin linearly increased Cr absorption (P = 0.02) and elimination (P = 0.04) rate and linearly decreased mean retention time of Cr (P = 0.02). Aspirin tended to increase jejunal claudin-1 mRNA expression (P = 0.10) but did not affect serum IL-6 or LBP or expression of other jejunal tight junction mRNA (P ≥ 0.20). This study indicates that aspirin disrupts GIT barrier function in beef cattle and has potential as a model in GIT permeability research.