Gene expression and morphological changes in the intestinal mucosa associated with increased permeability induced by short‐term fasting in chickens

Abstract

Short-term fasting for 4.5 and 9 hr has been demonstrated to increase intestinal permeability (IP) in chickens. This study aimed to investigate the effects of 0, 4.5, 9 and 19.5 hr fasting on intestinal gene expression and villus-crypt architecture of enterocytes in jejunal and ileal samples. On day 38, Ross-308 male birds were fasted according to their group and then euthanised. Two separate intestinal sections (each 2 cm long, jejunum and ileum) were collected. One section was utilised for villus height and crypt depth measurements. The second section was snap-frozen in liquid nitrogen for quantitative polymerase chain reaction (qPCR) analysis of tight junction proteins (TJP) including claudin-1, claudin-3, occludin, zonula occludens (ZO-1, ZO-2), junctional adhesion molecules (JAM) and E-cadherin. Additionally genes involved in enterocyte protection including glucagon-like peptide (GLP-2), heat-shock protein (HSP-70), intestinal alkaline phosphatase (IAP), mammalian target of rapamycin (mTOR), toll-like receptors (TLR-4), mucin (MUC-2), cluster differentiation (CD-36) and fatty acid-binding protein (FABP-6) were also analysed. Normally distributed data were analysed using one-way analysis of variance ANOVA. Other data were analysed by non-parametric one-way ANOVA. Villus height and crypt depth were increased (p < .05) only in the ileum after fasting for 4.5 and 9 hr compared with non-fasting group. mRNA expression of claudin-3 was significantly reduced in the ileum of birds fasted for 9 and 19.5 hr, suggesting a role in IP modulation. However, all other TJP genes examined were not statistically different from control. Nevertheless, ileal FABP-6 of all fasted groups was significantly reduced, which could possibly be due to reduced bile acid production during fasting.

Diet Supplementation with a Bioactive Pomace Extract from Olea europaea Partially Mitigates Negative Effects on Gut Health Arising from a Short-Term Fasting Period in Broiler Chickens

“…In addition, the expression of the anti-inflammatory cytokine TGF-β4, and that of HSP-70 included in tissue protection and repair were not affected by the short-term fasting. This is in agreement with Gilani et al [30], who showed the absence of changes in HSP-70 gene expression in the jejunum and ileum of up to 19.5 h fasted chickens. Taken together with these results, it seems that feed withdrawal for 15.5 h induced an intestinal inflammatory response through TLR4 signaling.…”

“…On the other hand, fasting period significantly reduced FABP6 expression in the ileum, corroborating results showed by Gilani et al [30]. This protein is involved in bile acid transport across the epithelium, and, according to Gilani et al [30], FABP6 downregulation in fasted birds might indicate a reduced bile acid production as a consequence of dietary fatty acid absence. Furthermore, considering the described effect of several dietary components (e.g., glutamine, fatty acids) and bacteria on claudin expression [37], it seems plausible that the lack of nutrients during fasting might affect Claudin-1 expression and increase permeability.…”

“…Despite the fact that a decreased expression of Claudin-1 has been related with an increased permeability in intestinal disorders, there seems not to be a clear pattern for Claudin-3 expression, which may or may not be affected [38]. On the other hand, fasting period significantly reduced FABP6 expression in the ileum, corroborating results showed by Gilani et al [30]. This protein is involved in bile acid transport across the epithelium, and, according to Gilani et al [30], FABP6 downregulation in fasted birds might indicate a reduced bile acid production as a consequence of dietary fatty acid absence.…”

“…Claudins are important structural components of the tight junctions and Claudin-1 and -3 are directly involved in the paracellular permeability [37]. In a recent study, Gilani et al [30] reported a decreased expression of Claudin-3 but no effect on Claudin-1 and other tight junction proteins in short-term fasted birds. Despite the fact that a decreased expression of Claudin-1 has been related with an increased permeability in intestinal disorders, there seems not to be a clear pattern for Claudin-3 expression, which may or may not be affected [38].…”

Effects of different stocking densities on the trachea barrier function and its plasma metabolic profile of finishing broilers

“…Barrier function is often determined by tight junction integrity of epithelial layers because tight junction plays an important role in sealing the apical gaps [33]. The decreased expression of tight junction-related genes and proteins has been considered a molecular evidence for impaired barrier functions [34]. Therefore, we measured selected tight junction-related protein expression in the trachea mucosa.…”