Brush Border Enzyme Activities Research Articles

Effect of method of delivery of sodium butyrate on maturation of the small intestine in newborn calves

The effect of sodium butyrate (SB) supplementation in milk replacer (MR), starter mixture (SM), or both on small intestine maturation in newborn calves was investigated. Twenty-eight male calves with a mean age of 5 (±1) d were randomly allocated into 1 of 4 groups (7 animals per group) and fed (1) MR and SM, without SB (MR− and SM−, respectively; MR−/SM−); (2) MR− and SM supplemented with SB encapsulated within triglyceride matrix (SM+, 0.6% as fed; MR−/SM+); (3) MR supplemented with crystalline SB (MR+, 0.3% as fed) and SM− (MR+/SM−); or (4) MR+ and SM+ (MR+/SM+). The MR was offered in amounts equal to 10% of initial body weight of the calf. The SM was blended with whole corn grain (50/50; wt/wt) and offered ad libitum as a starter diet. Calves were slaughtered at 26d (±1) of age and small intestine development was investigated. Treatment with MR+ decreased villus height in the proximal jejunum and decreased villus height, crypt depth, and tunica mucosa thickness in the middle jejunum, whereas treatment with SM+ tended to increase small intestine weight and crypt depth in the proximal jejunum, and increased villus height in the distal jejunum. In the duodenum, crypt depth and tunica mucosa thickness were greater for the MR−/SM+ group compared with MR−/SM−, MR+/SM−, and MR+/SM+ groups. In the ileum, crypt depth was less for MR−/SM+ compared with MR−/SM−. Supplementation with SB in both MR and SM enhanced cell proliferation and decreased apoptosis in the middle jejunum mucosa. Regarding brush border enzyme activities, addition of SB to MR increased lactase activity in the middle jejunum and maltase activity in the distal jejunum, and tended to increase lactase activity in the distal jejunum, aminopeptidase A activity in the middle jejunum and ileum, and aminopeptidase N activity in the ileum. In contrast, SM+ increased dipeptidylpeptidase IV activity in the distal jejunum and tended to increase aminopeptidase N in the distal jejunum. In conclusion, both MR+ and SM+ affected small intestine development in newborn calves. This effect depended on the method of SB delivery but MR+ generally had a more pronounced effect. No synergistic effect of SB supplementation into MR and SM was found.

Intestinal response to myeloablative chemotherapy in piglets

Chemotherapy-induced myeloablation prior to allogeneic hematopoietic stem cell transplantation (HSCT) may be associated with severe toxicity. The current understanding of the pathophysiology of oral and gastrointestinal (GI) toxicity is largely derived from studies in rodents and very little is known from humans, especially children. We hypothesized that milk-fed piglets can be used as a clinically relevant model of GI-toxicity related to a standard conditioning chemotherapy (intravenous busulfan, Bu plus cyclophosphamide, Cy) used prior to HSCT. In study 1, dose-response relationships were investigated in three-day-old pigs (Landrace × Yorkshire × Duroc, n = 6). Pigs were given one of three different dose combinations of Bu and Cy (A: 4 days Bu, 2 × 1.6 mg/kg plus 2 days Cy, 60 mg/kg; B: 4 days Bu, 2 × 0.8 mg/kg plus 2 days Cy, 30 mg/kg; C: 2 days Bu at 2 × 1.6 mg/kg plus 1 day Cy, 60 mg/kg) and bone marrow was collected on day 11. Histology of bone marrow samples showed total aplasia after treatment A. Using this treatment in study 2, Bu-Cy pigs showed lowered spleen and intestinal weights and variable clinical signs of dehydration, sepsis, and pneumonia at tissue collection. Oral mucositis was evident as ulcers in the soft palate in 4/9 Bu-Cy pigs and villus height and brush-border enzyme activities were reduced, especially in the proximal intestine. There were no consistent effects on tissue cytokine levels (IL-8, IL-6, IL-1β, TNF-α) or blood chemistry values (electrolytes, liver transaminases, bilirubin, alkaline phosphatase), except that blood iron levels were higher in Bu-Cy pigs. We conclude that a myeloablative Bu-Cy regimen to piglets results in clinical signs comparable to those seen in pediatric patients subjected to myeloablative treatment prior to HSCT. Piglets may be used as a model for investigating chemotherapy-induced toxicity and dietary and medical interventions.

Effect of antioxidant supplementation on digestive enzymes in radiation induced intestinal damage in rats

Purpose: Intestinal mucosa, a rapidly proliferating tissue, is highly sensitive to radiation and undergoes apoptosis as a consequence of over generation of oxidative free radicals and the lack of the antioxidants. Thus the present study was designed to investigate the intestinal damage induced by radiation and to study if supplementation of the diet with antioxidant vitamins could ameliorate the intestinal damage and its digestive activity, as determined by the expression of various border enzymes.Materials and methods: Swiss Albino rats (150–200 g body weight) were divided into six groups. Group I: Control untreated; Group II: Irradiated; Group III: Irradiated + vitamin A; Group IV: Irradiated + vitamin C; Group V: Irradiated + vitamin E; and Group VI: Irradiated + lycopene. Animals were exposed to whole body γ-radiation from 60Co at the rate of 8 Gy for 15 min/rat. Intestinal morphology and changes in various digestive enzymes together with, DNA damage was studied in six groups and each group consisted of 18 animals.Results: The gastrointestinal toxicity resulted in malabsorption, diarrhoea, weight loss, loss of appetite, abdominal haemorrhage and hair loss. The activities of sucrase and alkaline phosphatase were elevated and those of lactase, leucine aminopeptidase (LAP) and gamma-glutamyl transpeptidase or tranferase (γ-GTP) were markedly reduced. Antioxidant vitamin A, C or E supplementations prevented changes in brush border enzyme activities as compared to lycopene administration in rat intestine by radiation exposure. Intestinal histology showed that the vitamin supplementation to irradiated rats minimized the intestinal damage in rats.Conclusion: These findings suggest that the epithelial lining of the intestine is highly sensitive to radiation exposure and supplementation of antioxidant vitamins is helpful in minimizing the intestinal damage and supplementation by vitamin E was most potent in ameliorating the intestinal aberrations.

Premature Delivery Reduces Intestinal Cytoskeleton, Metabolism, and Stress Response Proteins in Newborn Formula‐Fed Pigs

Preterm infants often show intolerance to the first enteral feeds, and the structural and functional basis of this intolerance remains unclear. We hypothesized that preterm and term neonates show similar gut trophic responses to feeding but different expression of intestinal functional proteins, thus helping to explain why preterm neonates are more susceptible to feeding-induced disorders such as necrotizing enterocolitis (NEC). Incidence of feeding-induced NEC, intestinal mass, and brush border enzyme activities, and the intestinal proteome in preterm cesarean-delivered pigs were compared with the corresponding values in pigs delivered spontaneously at term. For both preterm and term pigs, mucosal mass and maltase activity increased (50%-100%), whereas lactase decreased (-50%), relative to values at birth. Only preterm pigs were highly NEC sensitive (30% vs 0% in term pigs, P < 0.05). By gel-based proteomics, 36 identified proteins differed in expression, with most proteins showing downregulation in preterm pigs, including proteins related to intestinal structure and actin filaments, stress response, protein processing, and nutrient metabolism. Despite that enteral feeding induces rapid gut tropic response in both term and preterm neonates, the expression level of cellular proteins related to mucosal integrity, metabolism, and stress response differed markedly (including complement 3, prohibitin, ornithine carbamoyltransferase, and arginosuccinate synthetase). These proteins may play a role in the development of functional gut disorders and NEC in preterm neonates.

Bovine colostrum improves intestinal function following formula-induced gut inflammation in preterm pigs

Only few hours of formula feeding may induce proinflammatory responses and predispose to necrotizing enterocolitis (NEC) in preterm pigs. We hypothesized that bovine colostrum, rich in bioactive factors, would improve intestinal function in preterm pigs following an initial exposure to formula feeding after some days of total parenteral nutrition (TPN). After receiving TPN for 2 days, preterm pigs were fed formula (FORM, n = 14), bovine colostrum (COLOS, n = 6), or formula (6 h) followed by bovine colostrum (FCOLOS, n = 14). Intestinal lesions, function, and structure, abundance and location of bacteria, and inflammation markers were investigated. NEC severity and interleukins (IL)-1β and -8 protein concentrations were lower, while villus height, galactose absorption, and brush-border enzyme activities were increased in the distal small intestine in COLOS and FCOLOS pigs, relative to FORM pigs. Intestinal gene expression of serum amyloid A, IL-1β, -6 and -8, and bacterial abundance, correlated positively with NEC severity of the distal small intestine. Bovine colostrum restores intestinal function after initial formula-induced inflammation in preterm pigs. Further studies are required to test if bovine colostrum may also benefit preterm infants during the challenging transition from total parenteral nutrition to enteral nutrition, when human milk is unavailable.

The effect of N‐butyl‐deoxynojirimycin on the structure, function and trafficking of intestinal glycoproteins

N‐butyl‐deoxynojirimycin (NB‐DNJ) is a synthetic analogue of D‐glucose which is used for treatment of the Niemann‐Pick Type C and Gaucher diseases. This drug is consumed orally and in most of the cases gives rise to gastrointestinal intolerances similar to congenital carbohydrate intolerance disorders, strongly suggesting that the activities of the disaccharidases in the intestine are affected. We have investigated the role of NB‐DNJ on the major disaccharidases of the intestinal epithelium. Our findings show that an immediate effect of NB‐DNJ is its interference with carbohydrate digestion in the intestinal lumen via reversible inhibition of disaccharidases that cleave α‐glycosidically linked carbohydrates. NB‐DNJ elicits also long term effects on the biosynthesis and processing of intestinal glycoproteins. Thus it reduces the trafficking rates of these proteins, since it interferes with their N‐glycosylation in the ER. These altered glycoforms lose partially their enzymatic function, yet their folding pattern does not grossly change as assessed by the similar proteolytic pattern of the various glycoforms. Therefore a reduction in the activities of brush border enzymes in the apical membrane of intestinal cells occurs due to the combinatorial effects of NB‐DNJ on the trafficking and N‐glycan pattern as well as the immediate inhibition of the enzymes of the brush border membrane.

In vitro Effects of Ethanol on Intestinal Epithelial Cell Glycosylation in Rats

Ethanol ingestion is known to influence intestinal glycosylation, epithelial cell morphology, luminal micro ecology and produces mal-absorption in mammals. In the present study, the effect of 6% ethanol on glycosylation and various enzyme systems was investigated in isolated epithelial cells in vitro. The activities of various brush border enzymes were reduced 10-30% in epithelial cells by ethanol exposure. Chemical analysis, revealed an increase in membrane sialic acid (70%) and total hexosamine (122%), and reduction in fucose (32%) and hexoses (18%) contents of ethanol treated cells compared to controls. The observed changes in sialylation and fucosylation were corroborated by binding of biotinylated Wheat germ agglutinin (WGA; affinity for N-acetylglucosamine and sialic acid) and Ulex europaeus agglutinin (UEA; affinity for α-L-fucose). Solid phase lectin binding assay showed a 65% increase in WGA and a 37% decrease in UEA reactivity in ethanol exposed cells compared to controls. These findings indicate that ethanol exposure modulates the glycosylation process in intestinal cells in vitro, which is similar to that seen under in vivo conditions. This may provide an in vitro assay system of ethanol toxicity, which could be of pathological significance.

A prospective study comparing histology and enteric enzyme function of patients with extrahepatic portal vein obstruction before and after shunt surgery

This was a prospective observational study carried out to objectively assess the effect of shunt surgery on intestinal morphology and function in patients with extrahepatic portal vein obstruction (EHPVO) and correlate it with growth improvement. Twenty patients who were operated upon for EHPVO were divided into two groups for the purpose of analysis depending on the outcome of surgery: group A--patients who underwent successful shunt surgery (n=14) and group B--patients who underwent splenectomy with devascularization (n=1) and those with thrombosed shunts (n=5). The patient groups were created on the basis of the type and outcome of the surgery and not prospective stratification. Growth parameters, endoscopy findings, duodenal histology, brush border enzyme activity, urinary D-xylose levels, fecal steatocrit, fecal α-1 antitrypsin, serum growth hormone and insulin-like growth factor-1 levels, and quality-of-life scores were assessed before surgery and at a mean of 24.9 weeks after surgery. There was no significant difference between the preoperative and postoperative duodenal histology. Preoperative brush border lactase activity was significantly lower than normal and did not change significantly after surgery. EHPVO did not affect intestinal absorption or permeability. Shunt surgery resulted in significantly improved z scores for height after surgery as well as quality of life. There was no significant growth hormone resistance. Our patients did not have any significant malabsorption or abnormality in small intestinal structure and function when compared with established normal levels. There was no significant change in the above parameters after shunt surgery, although an improvement in growth was observed. Thus, factors other than enteropathy or other lesser known enteral factors seem to be responsible for the growth retardation observed in EHPVO and its subsequent improvement after shunt surgery.

Antibiotics Increase Gut Metabolism and Antioxidant Proteins and Decrease Acute Phase Response and Necrotizing Enterocolitis in Preterm Neonates

BackgroundThe appropriate use of antibiotics for preterm infants, which are highly susceptible to develop necrotizing enterocolitis (NEC), is not clear. While antibiotic therapy is commonly used in neonates with NEC symptoms and sepsis, it remains unknown how antibiotics may affect the intestine and NEC sensitivity. We hypothesized that broad-spectrum antibiotics, given immediately after preterm birth, would reduce NEC sensitivity and support intestinal protective mechanisms.Methodology/Principal FindingsPreterm pigs were treated with antibiotics for 5 d (oral and systemic doses of gentamycin, ampicillin and metrodinazole; AB group) and compared with untreated pigs. Only the untreated pigs showed evidence of NEC lesions and reduced digestive function, as indicated by lowered villus height and activity of brush border enzymes. In addition, 53 intestinal and 22 plasma proteins differed in expression between AB and untreated pigs. AB treatment increased the abundance of intestinal proteins related to carbohydrate and protein metabolism, actin filaments, iron homeostasis and antioxidants. Further, heat shock proteins and the complement system were affected suggesting that all these proteins were involved in the colonization-dependent early onset of NEC. In plasma, acute phase proteins (haptoglobin, complement proteins) decreased, while albumin, cleaved C3, ficolin and transferrin increased.Conclusions/SignificanceDepressed bacterial colonization following AB treatment increases mucosal integrity and reduces bacteria-associated inflammatory responses in preterm neonates. The plasma proteins C3, ficolin, and transferrin are potential biomarkers of the colonization-dependent NEC progression in preterm neonates.

Correlation between villous height and the disaccharidase activity in the small intestine of piglets from nursing to growing

Early weaning induces villous atrophy in the small intestine. Reduction in villous height in the small intestine after weaning is associated with reductions in brush-border enzyme activity. Body weight gain after weaning is, therefore, correlated with villous height. This evidence suggested that the maintenance of small intestinal structure and function after weaning is important for the growth of young pigs. On the other hand, the relationship between villous height and the activity of the digestive enzymes in the small intestine has not been studied with piglets from the suckling to the growing period. Five suckling piglets, four piglets in the proximal stage of weaning, four pigs in the distal stage of weaning and four growing pigs were used. The activities of lactase (LA), sucrase (SA) and maltase (MA) were determined. LA showed a positive correlation with villous height in weaning. SA and MA were positively correlated with villous height from suckling to growing. In a previous study, non-infectious dyspeptic diarrhea was frequently observed in growing piglets on Japanese swine farms. The maintenance of villous height to retain disaccharidase activity may prevent dyspepsic diarrhea in this stage.

Bifidobacterium Infantis 35624 Protects Against Salmonella -Induced Reductions in Digestive Enzyme Activity in Mice by Attenuation of the Host Inflammatory Response

OBJECTIVES:Salmonella-induced damage to the small intestine may decrease the villi-associated enzyme activity, causing malabsorption of nutrients and diarrhea, and thus contribute to the symptoms of infection. The objective of this study was to determine the mechanism by which different doses and durations of Salmonella infection and lipopolysaccharide (LPS) affect brush border enzyme activity in the mouse, and to determine if the probiotic Bifidobacterium longum subspecies infantis 35624 could attenuate the intestinal damage.METHODS:BALB/c mice were challenged with Salmonella enterica serovar Typhimurium UK1 at various doses (102–108 colony-forming unit (CFU)) and durations (106 CFU for 1–6 days). Mice were also treated with B. longum subsp. infantis 35624 for 2 weeks before and during a 6-day S. Typhimurium challenge (106 CFU), or before injection of LPS. The small intestine was assessed for morphological changes, mRNA expression of cytokines, and activity of the brush border enzymes sucrase–isomaltase, maltase, and alkaline phosphatase.RESULTS:S. Typhimurium infection significantly reduced the activity of all brush border enzymes in a dose- and time-dependent manner (P<0.05). This also occurred following injection of LPS. Pre-treatment with B. longum subsp. infantis 35624 prevented weight loss, protected brush border enzyme activity, reduced the small intestinal damage, and inhibited the increase in interleukin (IL)-10 and IL-8 expression due to Salmonella challenge.CONCLUSIONS:Salmonella infection reduces the small intestinal brush border enzyme activity in mice, with the level of reduction and associated weight loss increasing with dose and duration of infection. B. longum subsp. infantis 35624 treatment attenuated the effect of Salmonella infection on brush border enzyme activity and weight loss, which may be due to modulation of the host immune response.

Influence of age and Enterococcus faecium NCIMB 10415 on development of small intestinal digestive physiology in piglets

This study aimed at studying the effect of age and Enterococcus faecium NCIMB 10415 on jejunal physiological measures in suckling and weaned piglets. A total of 112 piglets from 16 landrace sows were used. Sows received either no probiotic (n=8, control) or were fed a diet with 4.2 to 4.3×106cfu/g E. faecium NCIMB 10415 (n=8, EF) from 28days ante partum onwards. Piglets were offered creep feed beginning at 12 d of age and piglets were weaned to a pre-starter diet at 26 d of age. For EF piglets, the creep feed (pre-starter) and starter diets contained 5.1×106cfu/g and 3.6×106cfu EF/g, respectively. Twenty-seven randomly selected piglets from each group were euthanized at 12 (n=6), 26 (n=6), 34 (n=7), and 54d (n=8) of age and a 45cm mid-jejunal segment was taken. Histomorphometry was performed and relative transcript abundance of caspase-3, proliferating cell nuclear antigen, intestinal alkaline phosphatase (IAP), lactase-phlorizin hydrolase (LPH), sucrase (SUC), aminopeptidase-N (APN) and sodium/glucose cotransporter 1 (SGLT1) was determined. Lactase (LAC), maltase (MAL), SUC, APN and IAP activities were measured in brush border membranes. The EF treatment did not affect (P>0.05) performance variables like the pre- or post-weaning daily weight gain, feed intake, incidence of diarrhoea and ileal and total tract nutrient digestibility, except the feed conversion ratio which was reduced (P=0.033). Jejunal villus length and crypt depth did not differ between groups (P>0.05) but increased age-dependently (P=0.003 and P<0.001, respectively). Feeding EF did not markedly influence brush border enzyme expression or activity. Enzyme activity increased (SUC, MAL) or decreased (LAC, IAP) with age reflecting maturation and adaptation to creep feed (P<0.001). The gene expression of SUC, SGLT1 and IAP changed over time (P=0.012, P=0.003 and P=0.013). Furthermore, gene expression was not affected by treatment. The current study suggests that EF did not markedly affect physiological variables associated with digestive function. Age of piglets seems to be the main factor determining function and morphology of the jejunal tissue, reflecting both maturation and adaptation to creep feed.

Protein hydrolysates from yeast and pig blood as alternative raw materials in microdiets for gilthead sea bream (Sparus aurata) larvae

In this study, we have evaluated the incorporation of two types of protein hydrolysates at 9 and 12% levels of inclusion, one from yeast (Saccharomyces cerevisiae, YPH) and another one from pig blood (PBPH), in microdiets for gilthead sea bream (Sparus aurata) larvae, and compared these results to a microdiet containing fish protein hydrolysate and another group only fed with enriched live prey (rotifers and Artemia). The trial consisted in substituting up to 75% (wt/wt) the enriched Artemia with the experimental microdiets from 15 to 40days post-hatch, whereas larvae were exclusively fed on microdiets from 40 to 55dph. Protein hydrolysates used in the present study were obtained from different raw materials (yeast, pig blood and fish protein concentrate) and differed in their amino acid (AA) profile and in their molecular weight distribution. YPH and PBPH were mainly composed by free amino acids (FAA) (44%, MW<200Da), di- and tripeptides (50%, 200<MW<500Da) and 6% of larger polypeptides (500<MW<2500Da); whereas the fish protein hydrolysate (FPH) did only contain a minor quantity of FAA (1.5%) and was mainly composed of di- and tripeptides (36.5%) and larger polypeptides (51.4%, 500<MW<2500Da). The contents in FAA and di- and tripeptides in the microdiet containing FPH were 0.2 and 4.4%, respectively. FAA levels in microdiets including YPH and PBPH at 9 and 12% were 4.0 and 5.3%, whereas levels of di- and tripeptides were 4.5 and 6.0%, respectively. Results revealed that FPH in microdiets for marine fish larvae may be replaced by alternative protein hydrolysates obtained from yeast and pig blood, as fish fed with those diets performed, in terms of growth, survival, level of maturation of the enterocytes (activity of cytosolic and brush border enzymes) and incidence of skeletal deformities, as well as those larvae fed with only enriched live preys (rotifers and Artemia). Using YPH and PBPH, the inclusion level of protein hydrolysate in microdiets might be reduced to 9% (3% lesser to actual practices using fish protein hydrolysates) without affecting larval performance. Present results suggested the importance of leucine, valine and phenylalanine in fish larval skeletogenesis and in the appearance of skeletal disorders.

Prematurity does not markedly affect intestinal sensitivity to endotoxins and feeding in pigs

Preterm neonates show enhanced sensitivity to nutrient maldigestion and bacteria-mediated gut inflammatory disorders, such as necrotising enterocolitis (NEC). We hypothesised that preterm birth increases the sensitivity of intestinal nutrient absorption to endotoxins and that feeding after birth reduces this response. Hence, we investigated the postnatal development of nutrient digestive and absorptive capacity in the preterm and term pig intestine, and its responsiveness to endotoxins. Pigs were delivered by caesarean section at preterm (n 20) or term (n 17) gestation, and the small intestine was collected at birth or after 2 d of colostrum feeding, followed by ex vivo stimulation with lipopolysaccharide endotoxins and mixed gut contents collected from pigs with NEC. Brush border enzyme activities were reduced in newborn preterm v. term pigs (39-45 % reduction, P < 0.05), but normalised after 2 d of feeding. Ex vivo leucine and glucose uptake increased with prenatal age. Bacterial stimulation reduced the nutrient uptake similarly at birth and after 2 d in preterm and term pigs (23-41 % reduction, P < 0.05), whereas IL-6 and TNF-α expression was stimulated only at birth. Toll-like receptor-4 expression increased markedly at day 2 for preterm and term pigs (22-33-fold, P < 0.05) but with much lower expression levels in newborn preterm pigs (approximately 95 %, P < 0.01). In conclusion, digestive and absorptive functions mature in the prenatal period, but are similarly affected by postnatal feeding and bacterial exposure in both preterm and term pigs. Nutrient maldigestion may contribute to NEC development, while a prematurity-related hyper-responsiveness to endotoxins could be less important, at least in pigs.

Biochemical and histological changes in the small intestine of mice with dextran sulfate sodium colitis

The dextran sulfate sodium (DSS) model of colitis has been commonly utilized in mice to assess novel treatments for ulcerative colitis. Recent studies have indicated that morphological and biochemical changes extend to the small intestine (SI). This study aimed to characterize histological and biochemical changes in the SI during DSS colitis in wild-type (WT) and DPIV knock-out (DPIV(-/-) ) mice treated with saline or the DPIV inhibitors, Ile-Pyrr-(2-CN)*TFA or Ile-Thia. Groups (n = 10) of DPIV(-/-) and WT mice were orally gavaged twice daily with saline, Ile-Pyrr-(2-CN)*TFA or Ile-Thia. Mice consumed 2% DSS in drinking water for 6 days to induce colitis. Small intestinal tissue was assessed for histological changes, sucrase, and DPIV activity and neutrophil infiltration. Jejunal villus length was increased in all groups after 6 days DSS consumption (P < 0.05). Jejunal DPIV activity was significantly lower by 35% in WT mice receiving Ile-Pyrr-(2-CN)*TFA compared to saline controls. Jejunal MPO activity was significantly increased in the WT + saline and DPIV(-/-) + saline groups following DSS consumption, compared to WT and DPIV(-/-) controls at day 0. Increased sucrase activity was apparent at day 0 in DPIV(-/-) compared to WT mice (P < 0.05). We conclude that DSS-induced damage is not restricted to the colon, but also extends to the small intestine. Furthermore, reduced or absent DPIV activity resulted in functional adaptations to brush border enzyme activity. DPIV inhibitors are now a recognized therapy for type-II diabetes. The work presented here highlights the need to delineate any long-term effects of DPIV inhibitors on SI function, to further validate their safety and tolerability.

Enteral Feeding In Utero Induces Marked Intestinal Structural and Functional Proteome Changes in Pig Fetuses

Intestinal adaptation from parenteral to enteral nutrition is crucial for survival and growth of newborns. Rapid feeding-induced gut maturation occurs immediately after birth in both preterm and term neonates, but it remains unclear whether the responses depend on factors related to birth transition (e.g. bacterial colonization, endocrine, and metabolic changes). We hypothesized that enteral feeding matures the immature intestine, even in fetuses before birth. Hence, control pig fetuses were compared with fetuses fed with milk formula for 24 h in utero. Gel-based proteomics showed that feeding-induced changes in 38 proteins, along with marked increases in intestinal mass and changes in activities of brush border enzymes. Physiological functions of the identified proteins were related to enterocyte apoptosis (e.g. caspase 1) and nutrient metabolism (e.g. citric acid cycle proteins). Many of the differentiated proteins were similar to those identified previously in preterm pigs fed with the same formula after birth, except that effects on proteins related to inflammatory lesions (e.g. heat shock proteins) were absent. Our results show that enteral feeding, independently of the birth transition, induces marked gut maturation and proteome change in the immature intestine. Hence, immediate postnatal feeding-induced gut changes are largely independent of factors related to the birth transition.

The Incidence of Necrotizing Enterocolitis Is Increased Following Probiotic Administration to Preterm Pigs 3

AbstractPreterm birth and necrotizing enterocolitis (NEC) is associated with inappropriate gut colonization and immunity, which may be improved by probiotic bacteria. Using a preterm pig model of NEC, we investigated the effects of probiotics on intestinal structure, function, microbiology, and immunology in the immediate postnatal period. Just after birth, caesarean-delivered preterm pigs were inoculated with Lactobacillus paracasei, Bifidobacteria animalis, and Streptococcus thermophilus (total 2.4 1010/d) either as live (ProLive, n = 14) or gamma-irradiated dead bacteria (ProDead, n = 12) and compared with controls (n = 14). All pigs received parenteral nutrition for 2 d followed by enteral formula feeding until tissue collection on d 5. Compared with control pigs, intestinal weight was lower and NEC incidence was higher in both groups given probiotics (64–67 vs. 14%; P<0.01). Hexose absorption, brush border enzyme activities, and gut barrier function were lower in the ProDead group compared with the other groups (P < 0.05), whereas live probiotics induced higher expression of the proinflammatory cytokines IL-1a and IL-6 (P < 0.05). Probiotics minimally affected gut colonization, except that live probiotics induced a higher density of B. animalis and lower bacterial diversity in the distal intestinal mucosa and lower SCFA concentrations in the colon (P < 0.05). The detrimental effects of probiotic bacteria in this study may relate to the specific strain and dose combination and may have involved the very immature gut immune system and low NEC incidence in the control group. It remains to be determined whether similar adverse responses to probiotics occur in preterm infants.

Prolonged feed deprivation does not permanently compromise digestive function in migrating European glass eels Anguilla anguilla

The effects of prolonged feed deprivation (40 days at 18° C) and re-feeding (30 days) on body mass, growth and the activity of selected pancreatic and intestinal enzymes were evaluated in migrating European glass eels Anguilla anguilla by comparison with a control group fed to satiation with hake Merluccius merluccius roe for the duration of the experiment. Feed deprivation resulted in mass loss and a reduction in digestive function, as revealed by a decrease in the total and specific activities of pancreatic (trypsin and α-amylase) and intestinal brush border (alkaline phosphatase and leucine aminopeptidase) enzymes. The total activity of intestinal brush border enzymes diminished after 5 days of feed deprivation, whereas that of pancreatic enzymes did not decrease until 10 days, indicating that the intestine is more sensitive to feed deprivation than the pancreas. Re-feeding A. anguilla that were starved for 40 days resulted in compensatory growth, with specific growth rates that were 2·6 times higher than the control group. This compensatory growth was associated with the recovery of trypsin and intestinal brush border enzyme activities, which were restored to control levels within 5 days of re-feeding. The ability to maintain pancreatic enzyme activity during 40 days of feed deprivation, and rapidly recover capacity for protein digestion upon re-feeding, would enable A. anguilla at this glass eel stage to withstand periods without food but rapidly provide amino acids for protein synthesis and growth when suitable food was available.

Diet‐Dependent Effects of Minimal Enteral Nutrition on Intestinal Function and Necrotizing Enterocolitis in Preterm Pigs

A rapid advance in enteral feeding is associated with necrotizing enterocolitis (NEC) in preterm infants. Therefore, minimal enteral nutrition (MEN) combined with parenteral nutrition (PN) is common clinical practice, but the effects on NEC and intestinal function remain poorly characterized. It was hypothesized that a commonly used MEN feeding volume (16-24 mL/kg/d) prevents NEC and improves intestinal structure, function, and microbiology in preterm pigs. After preterm birth pigs were stratified into 4 nutrition intervention groups that received the following treatments: (1) PN followed by full enteral formula feeding (OF group, n = 12); (2) PN supplemented with formula MEN and followed by full formula feeding (FF, n = 12); (3) PN plus colostrum MEN followed by formula feeding (CF, n = 12); (4) PN plus colostrum MEN followed by colostrum feeding (CC, n = 10). NEC was absent in the CC group but frequent in the other groups (50%-67%). Compared with other groups, CC pigs showed improved mucosal structures, brush border enzyme activities, and hexose absorption (all P < .05). Relative to formula MEN, colostrum MEN thus improved gut function but did not prevent later formula-induced gut dysfunction and NEC. However, in CF pigs, intestinal lesions were restricted to the colon, compared with all regions in OF and FF pigs, which indicated proximal protection of colostrum MEN. Bacterial composition was not affected by MEN, diet, or NEC outcomes, but bacterial load and concentrations of short-chain fatty acids were reduced in the MEN groups. Colostrum MEN improves intestinal structure, function, and NEC resistance in preterm pigs but does not protect against gut dysfunction and NEC associated with later full enteral formula feeding.

Specific roles of threonine in intestinal mucosal integrity and barrier function

Threonine is the second or third limiting amino acid in swine or poultry diets. This nutrient plays a critical role in the maintenance of intestinal mucosal integrity and barrier function, which can be indicated by intestinal morphology, mucus production (number of goblet cells), transepithelial permeability, brush border enzyme activity, and growth performance. Dietary threonine restriction may decrease the production of digestive enzymes and increase mucosal paracellular permeability. A large proportion of dietary threonine is utilized for intestinal-mucosal protein synthesis, especially for mucin synthesis, and there is no oxidation of threonine by enterocytes. Because mucin proteins cannot be digested and reused, intestinal mucin secretion is a net loss of threonine from the body. Luminal threonine availability can influence synthesis of intestinal mucins and other proteins. Under pathological conditions, such as ileitis and sepsis, threonine requirement may be increased to maintain intestinal morphology and physiology. Collectively, knowledge about the role of threonine in mucin synthesis is critical for improving gut health under physiological and pathological conditions in animals and humans.