A moderate threonine deficiency affects gene expression profile, paracellular permeability and glucose absorption capacity in the ileum of piglets☆☆☆

Abstract

High dietary threonine extraction by the digestive tract suggests that threonine contributes to maintain gut physiology. In the present study, we evaluated the impact of a low (6.5 g of threonine/kg diet; LT group) or a control well-balanced threonine diet (9.3 g of threonine/kg diet; C group) given to piglets for 2 weeks on ileal permeability and Na+-dependant glucose absorption capacity in Ussing chambers. The paracellular permeability was significantly increased in the ileum of LT compared to C piglets (P=.017). The Na+-dependent glucose absorption capacity showed a nonsignificant increase in the LT piglets. In addition, we analysed ileal gene expression profiles in the LT and C groups using porcine multitissue cDNA microarrays. Compared to the C piglets, the expression of 324 genes was significantly modified in the ileum of the LT piglets: 214 genes were overexpressed (145 annotated) and 110 were down-expressed (79 annotated). Among them, some are involved in immune and defense responses, energy metabolism and protein synthesis. Furthermore, microarray analysis highlights changes in the expression of the gene encoding for the sodium/glucose cotransporter (SGLT1) and of genes involved in the regulation of paracellular permeability (ZO-1, cingulin and myosin light chain kinase). In conclusion, our results indicate that a moderate threonine deficiency affects intestinal functionality.

Splanchnic tissues respond differently when piglets are offered a diet 30 % deficient in total sulfur amino acid for 10 days

“…Using the same animals, no change in the weights of the splanchnic tissues was observed in the present study, which agrees with observations indicating that a greater priority for nutrient utilization is given to (or taken by) the intestines than to other tissues [5,17]. The conservation of tissue weight of the small intestine may contribute to an effort to maintain the absorptive surface and functional capacity [25] and is in line with data where no change in the small intestine weight was observed in neonatal piglets fed a TSAA-deficient diet [16].…”

“…Stronger villus atrophy in the proximal than in the distal parts of the small intestine has also been observed by others [33,35]. However, Hamard et al [17,36] did not observe any intestinal atrophy in the proximal part of intestine in early-weaned piglets receiving a Thrlimiting diet during 2 weeks, but structural alterations might have occurred in an earlier time of the experiment. The selective atrophy in the proximal jejunum of the present study contrasts with the "first-come, firstserved" hypothesis discussed before.…”

“…A reduction in glutathione concentration and metabolism as a result of a TSAA deficiency has been reported in the intestine, liver, and kidneys of newborn pigs [16]. However, others observed that splanchnic tissues were relatively resistant to nutrient deficiencies [5,17,18]. The objective of this study is therefore to further explore and understand how splanchnic tissues respond to a limiting TSAA supply in terms of AA composition, protein synthesis and proteolysis, glutathione system, and morphological composition.…”

Effect of Milk Formula Protein Content on Intestinal Barrier Function in a Porcine Model of LBW Neonates

“…The analysis of TJ protein expression did not give more information about mechanisms involved because mRNA levels of ZO-1 and CGN did not correlate with the paracellular permeability (FD-4) variations. However, interpreting variations in ZO-1 mRNA expression in tissues is not as clear as in cell cultures because several authors have already observed variations in ZO-1 mRNA expression but no difference in ex vivo permeability in rats (27) or increase in ileal permeability but increase in ZO-1 mRNA expression (28). Similarly, it is difficult to predict the actual effect of the tendency for upregulation of CGN mRNA in the ileum of HP LBW piglets from the literature.…”

Perspective: The Potential Role of Essential Amino Acids and the Mechanistic Target of Rapamycin Complex 1 (mTORC1) Pathway in the Pathogenesis of Child Stunting

“…In rats or pigs fed a Villous atrophy in the ileum, no effect on protein metabolism in the small intestine, reduced amino acid and protein content in the liver, increased paracellular permeability in the ileum, alterations in gene expression of genes related to paracellular permeability threonine-deficient diet, a consistent finding was a reduced synthesis of mucins in the gut (142)(143)(144)(145)(146)(147). In addition, increased gut permeability was observed in piglets fed a diet with moderate threonine restriction (146). These findings suggest that an insufficient dietary intake of threonine could potentially contribute to the risk of environmental enteric dysfunction by compromising the protective mucin layer of the gut and increasing gut permeability.…”