149 Development of a leaky gut model: Impact of 24-h feed restriction on ileal expression of tight junction proteins in weaned pigs

Abstract

Abstract Weanling barrows, 26 to 28 d old [n = 90; Duroc terminal line Fast genetics, initial body weight (BW)= 5.63 ± 0.43 kg] were used to evaluate the effect of 24-h complete feed restriction on growth and intestinal integrity. Upon arrival at the NutriQuest modeling center (Fergus Falls, MN), pigs were weighed, blocked by BW, and randomly assigned to 1 of 30 pens. Five treatments were randomly assigned to 6 pens: 1) Positive Control (PC), and 4 treatments that had 24-hr feed restriction (FR); 2) Negative control (NC), 3) Direct Fed Microbial (DFM) A, 4) DFM B, and 5) DFM C. Feed intake and BW were determined weekly and before and after FR. All pigs were fed a common diet. Fifteen pigs were removed prior to FR due to enteric disease. On d 18, feed was removed from pigs on treatments 2 to 5 for 24 h. After 24 h, 8 pigs per treatment were harvested for tissue collection. Feed access was restored to the remaining pigs who were harvested 3 d later. Ileal samples were collected and immediately frozen. Plasma and fecal samples were collected upon arrival, at FR, and 24 h and 4-d post-FR. Ileal expression of claudin-3, occludin, and tight-junction-1 genes was determined using QuantStudio 3 Real Time PCR system. Fold-change in gene expression compared with NC was calculated for each treatment. Plasma samples were analyzed for LPS binding protein (LBP) concentration, and fecal samples were analyzed for myeloperoxidase (MPO) concentration. Pig (n = 75) was the experimental unit for BW, LBP, MPO, and gene expression data. Pen (n = 30) was the experimental unit for feed intake. Data were analyzed using PROC GLIMMIX of SAS. Preplanned orthogonal contrasts were performed to determine the effect of PC vs. 4 FR treatments. To determine the relationship of tight junction gene expression and LBP and MPO, PROC REG of SAS was used. Data are described as PC vs. FR treatments to focus on model development. Final BW for pigs on PC was greater compared with the FR treatments (P < 0.05; Table 1). From 1 to 4 d post-FR, average daily gain (ADG) for FR treatments was greater than PC (P < 0.01). There was no effect of treatment on feed intake or feed efficiency. Plasma LBP and fecal MPO concentrations were greater 24 h post-FR for pigs on PC compared with FR treatments (P < 0.01). Fold change in occludin and claudin-3 expression was greater for PC compared with FR treatments (P ≤ 0.05). For pigs euthanized 24 h post-FR, there was a positive relationship between LBP concentrations and occludin expression (P < 0.02). Twenty-four hour FR in weaned pigs alters ileal tight junction gene expression and plasma LBP concentrations; therefore, a timed FR event may serve as a model for leaky gut.