l-Methionine supplementation maintains the integrity and barrier function of the small-intestinal mucosa in post-weaning piglets

Abstract

This study was conducted to test the hypothesis that different dietary Met levels affect small-intestinal mucosal integrity in post-weaning piglets. Two groups of piglets (n = 6/group) were weaned at 28 days of age and randomly allotted to a basal diet (without extra Met supplementation) or a Met-supplemented diet (with 0.12% L-Met) for 14 days. The standardized ileal digestible (SID) Met levels were 0.24 and 0.35%, respectively. At days 7 and 14 of the trial, venous blood samples were obtained from piglets, followed by their euthanasia for tissue collection. Piglets fed the diet supplemented with L-Met had a higher average daily gain during days 7-14 and improved feed efficiency during the entire period. Concentrations of sulfur amino acids (SAA), glutamate acid (Glu), glutamine (Gln), and taurine in the plasma and tissues were higher for the piglets in the Met-supplemented group. Met supplementation increased cysteine (Cys) and glutathione (GSH) concentrations in the plasma and tissues, leading to reductions in plasma Cys/CySS redox potential and tissue GSH/GSSH redox potential. The small-intestinal mucosa of Met-supplemented piglets exhibited improved villus architecture, compared with control piglets. Met supplementation increased transepithelial electrical resistance of the jejunal mucosa. Transport of Met, Gln and Cys across the jejunal mucosa did not differ between control and Met-supplemented piglets. The abundance occludin was higher, whereas the abundance of active caspase-3 was lower, in the jejunum of the Met-supplemented piglets. Collectively, adequate dietary Met is required for optimal protein synthesis and mucosal integrity in the small intestine of post-weaning piglets.

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

“…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.…”

“…These findings suggest that TSAA may play a role in the control of intestinal growth and function by the regulation of the redox status. Moreover, the antioxidant and morphometric responses indicate that the proximal section of the gut is more affected than distal sections [33]. These authors also reported that the polyamine concentration is decreased more in the duodenum and jejunum than in the ileum when the Met supply is deficient.…”

“…Feeding a TSAA-free diet to neonatal pigs has been shown to result in a marked reduction in the glutathione concentration and in a reduced epithelial growth of the mucosa in the jejunum [16]. Similarly, Chen et al [33] observed a disrupted villus architecture and a reduced glutathione concentration in the duodenum and jejunum in pigs due to a deficient Met supply. Others also reported a link between reduced cell growth of the intestinal epithelium and glutathione reduction in the intestine [41,42].…”

“…Hamard et al [10] found that feeding a Thr-deficient diet to early-weaned pigs did not affect the AA composition of the small intestine but, as in the current study, major changes in AA composition of the liver were observed. Conversely, feeding postweaned piglets a Met-deficient diet for 14 days, Chen et al [33] found changed concentrations of only of Met in the liver and ileum, but of Met, Glu and Cys in the jejunum and duodenum. Chen et al [33] used L-Met in the control diet, whereas dl-Met was used in our study.…”

“…Conversely, feeding postweaned piglets a Met-deficient diet for 14 days, Chen et al [33] found changed concentrations of only of Met in the liver and ileum, but of Met, Glu and Cys in the jejunum and duodenum. Chen et al [33] used L-Met in the control diet, whereas dl-Met was used in our study. Although the transformation of d-Met to l-Met is generally assumed to occur with a 100 % efficiency in pigs, this transformation mainly occurs in the liver and kidneys.…”