Effects of oral glutamine supplementation on jejunal morphology, development, and amino acid profiles in male low birth weight suckling piglets

Abstract

Background It has been shown that small intestine development in low birth weight (LBW) piglets is impaired. Glutamine (Gln) has been reported to improve piglet health and intestinal function in weaned piglets, but data is scarce in suckling piglets. This study was conducted to investigate the effects of oral Gln supplementation compared to Alanine (Ala) on jejunal development and function in 5 and 12 d old male LBW and normal birth weight (NBW) suckling piglets. Results Gln had no effect on the jejunal morphology, development, tissue and digesta amino acid profiles and mRNA abundance of genes involved in amino acid transport, metabolism, glutathione synthesis in LBW piglets when compared to Ala supplementation and birth weight controls at 5 and 12 d. Only the concentration of Gln in jejunal tissue was higher in NBW piglets supplemented with Gln compared to Ala at 5 d (P < 0.05). A comparison of the birth weight groups showed no differences between LBW and NBW piglets at 5 and 12 d in any parameter. Jejunal crypt depth, villus height / width, tunica muscularis thickness, number of goblet and IgA positive cells, the ratio of jejunal RNA to DNA and the concentration of DNA, protein and RNA changed (P < 0.05) from 5 compared to 12 d. The concentrations of several free, and protein bound amino acids as well as amino metabolites differed between age groups in jejunal tissue but the digesta concentrations were affected to a lesser extent. Conclusions Oral Gln supplementation to suckling male piglets over the first 12 d of life was not associated with changes in jejunal parameters measured in this study. The absence of effects may indicate that Gln is absorbed as well as metabolized in the upper intestinal tract and thus could benefit intestinal development at a more proximal location.

Acute and persistent effects of oral glutamine supplementation on growth, cellular proliferation, and tight junction protein transcript abundance in jejunal tissue of low and normal birthweight pre-weaning piglets

“…In the current study the focus is on the comparison of piglets at age 12 and 26 days, to investigate whether the effects of Gln persist after cessation (day 12) of Gln supplementation. Therefore, previously published data on zootechnical measures, jejunal AA concentrations, jejunal cellular population and jejunal morphology of age day 5 and 12 piglets [ 31 , 32 ] were combined with the data from the day 26 group and re-analyzed. New data on tight junction protein mRNA abundances, and cell proliferation are presented for age groups 5, 12, and 26 days.…”

“…day 5 ( n = 48), 12 ( n = 48), and 26 ( n = 48), with 5 and 12 day groups examining the effects during supplementation, and the day 26 group, to study potential persistent effects beyond the supplementation period. However, the majority of the measurements in the day-5 age group has been reported previously [ 31 , 32 ].…”

“…with bromodeoxyuridine ( BrdU ) (12 mg/kg BW; Roche Diagnostics GmbH, Mannheim, Germany). Jejunal tissue was sampled as reported [ 32 ].…”

“…Leitz Wetzlar, Germany). Jejunal mucosa morphometry, number and mucin type of goblet cells were determined using paraformaldehyde fixed tissue, and Alcian blue pH 2.5 periodic acid Schiff staining, as previously described [ 32 ]. A microscope (Photomicroscope BX43F, Olympus, Tokyo, Japan) equipped with a digital camera (Olympus DP72, Tokyo, Japan) was used and images were analyzed with the cellSens imaging software (v. 1.4, Olympus).…”

“…We have previously shown that Gln supplementation from age 1 to 12 days has acute beneficial effects on the growth of LBW piglets while jejunal parameters showed little differences [ 31 , 32 ]. We hypothesize that Gln might have positive persistent effects on growth and jejunal development, potentially alleviating the subsequent negative effects of current weaning practices.…”