Acidomucin goblet cell expansion induced by parenteral nutrition in the small intestine of piglets

Total parenteral nutrition (TPN) impairs small intestine development and is associated with barrier failure, inflammation, and acidomucin goblet cell expansion in neonatal piglets. We examined the relationship between intestinal goblet cell expansion and molecular and cellular indices of inflammation in neonatal piglets receiving TPN, 80% parenteral + 20% enteral nutrition (PEN), or 100% enteral nutrition (control) for 3 or 7 days. Epithelial permeability, T cell numbers, TNF-alpha and IFN-gamma mRNA expression, and epithelial proliferation and apoptosis were compared with goblet cell numbers over time. Epithelial permeability was similar to control in the TPN and PEN jejunum at day 3 but increased in the TPN jejunum by day 7. By day 3, intestinal T cell numbers were increased in TPN but not in PEN piglets. However, goblet cell expansion was established by day 3 in both the TPN and PEN ileum. Neither TNF-alpha nor IFN-gamma mRNA expression in the TPN and PEN ileum correlated with goblet cell expansion. Thus goblet cell expansion occurred independently of overt inflammation but in association with parenteral feeding. These data support the hypothesis that goblet cell expansion represents an initial defense triggered by reduced epithelial renewal to prevent intestinal barrier failure.     

Growth and morphological changes in the small and the large intestine in piglets during the first three days after birth.

Growth and morphological changes in the small and the large intestine of piglets were examined during the first three days after birth. There was a 72% increase in small intestinal weight, virtually all of which occurred during the first day and was due primarily to a 115% increase in the weight of the mucosa. Associated with the tissue weight gain there was a 24% increase in small intestinal length, a 15% increase in small intestinal diameter, a 33-90% increase in villus height and a 14-51% increase in villus diameter, during the first day. The cellular population in the small intestinal mucosa, as indicated by its DNA content, increased progressively with age, and at three days had increased by 84-154%. The percentage increase in mucosal DNA content was highest in the duodenum, intermediate in the jejunum and lowest in the ileum. Histological features and tissue protein contents revealed a transient epithelial cellular swelling related to intracellular accumulation of protein on the first day. Protein accumulation was evident in the jejunum and ileum but not in the duodenum. The positions of the nuclei in the epithelial cells suggested that on the first day protein absorption was at a more advanced stage in the jejunum and the proximal ileum than in the distal ileum. Large intestinal weight increased by 33% during the first day and had doubled by the third day, and this weight gain was due to both mucosal and non-mucosal tissue growth. Villus-like structures were observed in the caecum and the proximal colon in piglets at birth and one day after birth but not in piglets three days after birth. It is speculated that such villus-like structures may have a functional significance during the transition to complete dependence on oral nutrition in newborns.     

Heat shock protein 70 is upregulated in the intestine of intrauterine growth retardation piglets

The objective of this study is to investigate the expression and distribution of heat shock protein 70 (Hsp70) in the intestine of intrauterine growth retardation (IUGR) piglets. Samples from the duodenum, prejejunum, distal jejunum, ileum, and colon of IUGR and normal-body-weight (NBW) piglets were collected at birth. The results indicated that the body and intestine weight of IUGR piglets were significantly lower than NBW piglets. The villus height and villus/crypt ratio in jejunum and ileum of IUGR piglets were significantly reduced compared to NBW piglets. These results indicated that IUGR causes abnormal gastrointestinal morphologies and gastrointestinal dysfunction. The mRNA of hsp70 was increased in prejejunum (P < 0.05), distal jejunum (P < 0.05), and colon in IUGR piglets. However, the hsp70 mRNA in ileum of piglets with IUGR was decreased. Similar to hsp70 mRNA, the protein levels of Hsp70 in prejejunum (P < 0.05), distal jejunum, and colon (P < 0.05) in IUGR piglets were higher than those in NBW piglets. These results indicated that the expression of Hsp70 in the intestinal piglets was upregulated by IUGR, and different intestinal sites had different responses to stress. Meanwhile, the localization of Hsp70 in the epithelial cells of the whole villi and intestinal gland rather than in the lamina propria and myenteron suggested that Hsp70 has a cytoprotective role in epithelial cell function and structure.     

Effect of Weaning on Small Intestinal Structure and Function in the Piglet

Fifty-four piglets were selected from 12 litters weaned at 17 (Treatment 1), 21 (Treatment 2), 28 (Treatment 3) and 35 (Treatment 4) days old, respectively, to determine the effect of weaning age on small intestinal villus morphology, immunology and histochemistry. From proximal duodenum, proximal jejunum, distal jejunum and middle ileum, intestinal samples with three replicates (piglets) in each treatment were taken at 18, 22, 28 and 36; 22, 28, 36 and 43; 28, 36, 43, and 50; and 18, 22, 28, 36, 43 and 50d of age in Treatment 1, 2, 3 and 4, respectively. This was equivalent to 12h, 3d, 1 week, 2 week postweaning in Treatment 1; 12h, 1 week, 2 week, 3 week postweaning in Treatment 2 and 3, and all the same age in Treatment 4 as in Treatment 1, 2, 3, respectively. The results showed that villous height of duodenum and proximal jejunum decreased significantly in Treatment 1 and 3. Crypt depth in the duodenum, proximal jejunum and ileum also decreased significantly in Treatment 1. Date had significant effect on villous height of the duodenum, distal jejunum and ileum with the shortest on day 29 and crypt depth of all positions increased with piglet age except the crypt depth in proximal jejunum decreased on day 50. Weaning age and day of age had significant effects on intraepithelial lymphocyte (IEL) number and goblet cell (GC) number at all positions of small intestinal mucosa in piglets. The number of IEL at all segments of small intestinal mucosa in Treatment 3 increased significantly compared to those in other treatments, but IEL number at all locations of small intestinal mucosa in Treatment 2 decreased significantly compared to those in other treatments. The number of GC in small intestinal mucosa increased significantly in early-weaned (< day 21) piglets. It appears that providing fluid milk replacer for a few days postweaning could dramatically reduce the negative impact of weaning on villous morphology and digestive and absorptive function, especially in pigs weaned prior to 3 week of age. Finally, as weaning age was reduced, GC had a greater role in intestinal duct protection.     

GLP-2 stimulates intestinal growth in premature TPN-fed pigs by suppressing proteolysis and apoptosis

We wished to determine whether exogenous glucagon-like peptide (GLP)-2 infusion stimulates intestinal growth in parenterally fed immature pigs. Piglets (106-108 days gestation) were given parenteral nutrient infusion (TPN), TPN + human GLP-2 (25 nmol. kg(-1). day(-1)), or sow's milk enterally (ENT) for 6 days. Intestinal protein synthesis was then measured in vivo after a bolus dose of [1-(13)C]phenylalanine, and degradation was calculated from the difference between protein accretion and synthesis. Crypt cell proliferation and apoptosis were measured in situ by 5-bromodeoxyuridine (BrdU) and terminal dUTP nick-end labeling (TUNEL), respectively. Intestinal protein and DNA accretion rates and villus heights were similar in GLP-2 and ENT pigs, and both were higher (P < 0.05) than in TPN pigs. GLP-2 decreased fractional protein degradation rate, whereas ENT increased fractional protein synthesis rate compared with TPN pigs. Percentage of TUNEL-positive cells in GLP-2 and ENT groups was 48 and 64% lower, respectively, than in TPN group (P < 0.05). However, ENT, but not GLP-2, increased percentage of BrdU-positive crypt cells above that in TPN piglets. We conclude that GLP-2 increases intestinal growth in premature, TPN-fed pigs by decreasing proteolysis and apoptosis, whereas enteral nutrition acts via increased protein synthesis and cell proliferation and decreased apoptosis.     

Transport mechanisms in chloride channels.

A comparative study of lipids and proteins in sarcoplasmic reticulum (SR) from rabbit and flounder has been undertaken. The protein/phospholipid ratio (w/w) was 3:1 in flounder SR (FSR) and 2.2:1 in rabbit SR (RSR). Both membranes had similar contents of PC (70%) and PI (6%). PE constituted 15% in RSR and 21% in FSR. PS and sphingomyelin were minor components of both SR (less than 4%). There were differences in the unsaturated chains of the total lipid extracts, PC, PE, and PI between FSR and RSR. RSR was high in linoleate and arachidonate while FSR contained substantial amounts of eicosapentaenoate and docosahexaenoate. FTIR spectroscopy revealed that the lipids of both membranes did not undergo a phase transition between 0 and 50 degrees C. The lipids were in the liquid-crystalline state at physiological temperatures and underwent monotonic increases in conformational disorder as the temperature was raised. CD spectra indicated higher content of alpha-helical structure of proteins in RSR than in FSR. Increasing temperature caused diminution of alpha-helix content. Relatively large decreases in ellipticity were observed between 20 degrees C and 40 degrees C for FSR and 30 degrees C and 60 degrees C for RSR. Measurements of intrinsic tryptophan fluorescence as a function of temperature gave similar results for membrane proteins in both FSR and RSR. The rate of change of tryptophan fluorescence and fluorescence lifetimes was constant over the temperature ranges studied, and no abrupt shifts in fluorescence occurred in the temperature regions where ellipticity decreased rapidly.     

Effect of glutamine on glutathione kinetics in vivo in dogs

To determine whether glutamine affects glutathione (GSH, gamma-glutamyl-cysteinyl-glycine) metabolism, seven healthy beagle dogs received 6-h infusions of [(15)N]glutamate and [(13)C]leucine after a 3-day fast. Isotope infusions were performed during oral feeding with an elemental regimen, supplemented with either l-glutamine or an isonitrogenous amino acid mixture, on two separate days and in randomized order. Timed blood samples were obtained, and a surgical duodenal biopsy was performed after 6 h of isotope infusion. GSH fractional synthesis rate (FSR) was assessed from [(15)N]glutamate incorporation into blood and gut GSH, and duodenal protein synthesis from [(13)C]leucine incorporation into gut protein. Glutamine supplementation failed to alter erythrocyte GSH concentration (2189+/-86 vs. 1994+/-102 micromol L(-1) for glutamine vs. control; ns) or FSR (64+/-17% vs. 74+/-20% day(-1); ns). In the duodenum, glutamine supplementation was associated with a 92% rise in reduced/oxidized GSH ratio (P=.024) and with a 44% decline in GSH FSR (96+/-15% day(-1) vs. 170+/-18% day(-1); P=.005), whereas total GSH concentration remained unchanged (808+/-154 vs. 740+/-127 micromol kg(-1); P=.779). We conclude that, in dogs receiving enteral nutrition after a 3-day fast: (1) glutamine availability does not affect blood GSH, and, (2) in contrast, in the duodenum, the preserved GSH pool, along with a decreased synthesis rate, suggests that glutamine may maintain GSH pool and intestinal redox status by acutely decreasing GSH utilization.     

Effects of the antimicrobial peptide cecropin AD on performance and intestinal health in weaned piglets challenged with Escherichia coli

This study was conducted to determine the effects of the antimicrobial peptide cecropin on performance and intestinal health in piglets. Newly weaned barrows were randomly assigned to one of three treatments (n=8), including a corn-soybean basal diet or similar diets supplemented with antibiotics (100 mg/kg kitasamycin plus 800 mg/kg colistin sulfate) or 400 mg/kg cecropin AD. On day 13, all piglets were orally challenged with 10(9)CFU/mL of Escherichia coli K88. On day 19, all piglets were euthanized and sampled. Before challenge, piglets fed antibiotics had greater weight gain, feed efficiency, nitrogen and energy retention than the control (P<0.05). E. coli challenge decreased weight gain, feed intake and feed efficiency for the control piglets (P<0.05) but not for the antibiotic or cecropin AD treated piglets. The incidence of diarrhea post-challenge in the antibiotic and cecropin AD treatments decreased compared with the control piglets. The total viable counts of cecal E. coli were lower while the Lactobacilli counts were higher in the antibiotic and cecropin AD treatments compared with the control (P<0.05). Cecropin AD treatment decreased total aerobes while increasing total anaerobes in the ileum (P<0.05). A higher villus height to crypt depth ratio in the jejunum and ileum as well as a deeper crypt depth in the jejunum and higher villus height in the ileum were observed in piglets fed antibiotics or cecropin AD compared with control piglets (P<0.05). Piglets fed the control diet had lower levels of secretory IgA in their jejunum and lower serum IgA, IgG, interleukin-1β and interleukin-6 compared with the other treatments (P<0.05). Overall, these data suggest that cecropin AD enhances pig performance through increasing immune status and nitrogen and energy retention as well as reducing intestinal pathogens in weaned piglets.     

Intestinal epithelial cell proliferation and migration in Atlantic salmon, Salmo salar L.: effects of temperature and inflammation

A 28-day feeding trial was carried out to characterise intestinal epithelial cell (IEC) turnover in Atlantic salmon (Salmo salar L.) post-smolts in seawater. Four groups of fish raised at two temperatures of 8°C or 12°C and fed two different diets were investigated. The diets included a reference maize gluten and fishmeal-based diet (FM) and an experimental enteropathy-causing diet containing 20% extracted soybean meal (SBM). IEC proliferation and migration were investigated by labelling cells with the in vivo proliferation marker 5-bromo-2′-deoxyuridine (BrdU). Proliferating cell nuclear antigen (PCNA) labelling was used as a control for identifying proliferating cells. Samples of the proximal (PI), mid (MI) and distal (DI) intestinal regions were collected at five time points (3 h–28 days) over the experimental period. Histologically, FM-fed fish had normal mucosa, whereas the SBM-fed fish developed DI enteropathy. Major zones of cell proliferation were observed in the mucosal fold bases for all intestinal regions. Over time, BrdU-labelled cells migrated up mucosal folds to the tips before being lost. Migration rates were dependent on intestinal region, temperature and diet. Highest migration rates were observed in the PI followed by the MI and DI for FM-fed fish. Diet and temperature barely affected migration in the PI and MI. Migration in the DI was most sensitive to diet and temperature, with both SBM and the higher water temperature increasing proliferation and migration rates. The slow IEC turnover in the DI might help to explain the sensitivity of this region to dietary SBM-induced enteropathy.     

Small intestine growth and morphometry in piglets weaned at 7 days of age. effects of level of energy intake

Two trials involving a total of 56 pigs were conducted to examine the effects of weaning at 7 d of age (trial 1) and of energy intake level and length of post-weaning underfeeding period (trial 2) on small intestinal (SI) development and morphometry. At 3 d after weaning, weight of the SI and mucosa (g/kg body weight) and villous height along SI were reduced by 20, 36 and 41%, respectively, compared to the day of weaning. Intestinal morphometrical changes are dependent on SI site and days post-weaning. Villous atrophy on d 3 and recovery on d 14 post-weaning were greater and occurred earlier in the proximal than in the medial and distal SI. Villous height was dependent on the level of energy intake which explains 56% of the variations in proximal SI villous height in weaned pigs and 73% when data of the sow-reared pigs were included in the analysis. Moreover, after 4 d of refeeding, underfed piglets showed similar villous characteristics to piglets fed a continuously high feeding level after weaning stressing that capacities of intestinal restoration were not affected by the length of the post-weaning underfeeding period. Overall, the present results suggest a spatial and temporal effect of weaning on villous atrophy and recovery, and that the level of energy intake is a major factor accounting for the post-weaning villous height.     

Increasing weaning age of piglets from 4 to 7 weeks reduces stress, increases post-weaning feed intake but does not improve intestinal functionality

This study tested the hypothesis that late weaning and the availability of creep feed during the suckling period compared with early weaning, improves feed intake, decreases stress and improves the integrity of the intestinal tract. In this study with 160 piglets of 16 litters, late weaning at 7 weeks of age was compared with early weaning at 4 weeks, with or without creep feeding during the suckling period, on post-weaning feed intake, plasma cortisol (as an indicator of stress) and plasma intestinal fatty acid binding protein (I-FABP; a marker for mild intestinal injury) concentrations, intestinal morphology, intestinal (macro)molecular permeability and intestinal fluid absorption as indicators of small intestinal integrity. Post-weaning feed intake was similar in piglets weaned at 4 weeks and offered creep feed or not, but higher (P < 0.001) in piglets weaned at 7 weeks with a higher (P < 0.05) intake for piglets offered creep feed compared with piglets from whom creep feed was witheld. Plasma cortisol response at the day of weaning was lower in piglets weaned at 7 weeks compared with piglets weaned at 4 weeks, and creep feed did not affect cortisol concentration. Plasma I-FABP concentration was not affected by the age of weaning and creep feeding. Intestinal (macro)molecular permeability was not affected by the age of weaning and creep feeding. Both in uninfected and enterotoxigenic Escherichia coli-infected small intestinal segments net fluid absorption was not affected by the age of weaning or creep feeding. Creep feeding, but not the age of weaning, resulted in higher villi and increased crypt depth. In conclusion, weaning at 7 weeks of age in combination with creep feeding improves post-weaning feed intake and reduces weaning stress but does not improve functional characteristics of the small intestinal mucosa.     

低蛋白质日粮对断奶仔猪生长相关激素和肠道微生物区系的影响

【目的】在饲喂低蛋白质日粮条件下,探究断奶仔猪生长相关激素、回肠和盲肠微生物组成及其代谢产物的变化。【方法】选取体重相近杜长大断奶仔猪54头,随机平均分为3组,每组18头,分别饲喂含20%(NP组)、17%(MP组)和14%(LP组)粗蛋白日粮,平衡日粮中的赖氨酸、蛋氨酸、苏氨酸和色氨酸,于试验第10、25和45天每组屠宰6头,采血测定血常规和生长相关激素;于第45天采集回肠和盲肠食糜,分析微生物及其代谢产物。【结果】与NP组相比,第25和45天时MP和LP组尿素氮水平显著降低(P0.05),第25天时LP组甘油三脂含量、第45天时LP组胆固醇含量显著增加(P0.05)。各时间点血液胰高血糖素、胰岛素、生长激素、T3和T4在3组之间差异均不显著。门水平上,回肠和盲肠中的微生物均以厚壁菌门占主导地位,但各组间差异不显著;随日粮蛋白质含量降低,乳酸杆菌属呈上升趋势,严格梭菌属呈下降趋势,但差异不显著。降低日粮蛋白质含量显著减少了回肠和盲肠中氨氮的产量(P0.05)。【结论】断奶仔猪日粮蛋白质降低3或6个百分点不影响机体生长相关激素的分泌,但能降低血液尿素氮和肠道内氨氮的浓度,对肠道有益菌乳酸杆菌属的相对丰度有一定的提高作用。这说明低蛋白质日粮能提高断奶仔猪对饲料氮源的利用率,且有利于肠道健康。     

Glycine is a nutritionally essential amino acid for maximal growth of milk-fed young pigs

Analysis of amino acids in milk protein reveals a relatively low content of glycine. This study was conducted with young pigs to test the hypothesis that milk-fed neonates require dietary glycine supplementation for maximal growth. Fourteen-day-old piglets were allotted randomly into one of four treatments (15 piglets/treatment), representing supplementation with 0, 0.5, 1 or 2 % glycine (dry matter basis) to a liquid milk replacer. Food was provided to piglets every 8 h (3 times/day) for 2 weeks. Milk intake (32.0–32.5 g dry matter/kg body weight per day) did not differ between control and glycine-supplemented piglets. Compared with control piglets, dietary supplementation with 0.5, 1 and 2 % glycine increased (P < 0.05) plasma concentrations of glycine and serine, daily weight gain, and body weight without affecting body composition, while reducing plasma concentrations of ammonia, urea, and glutamine, in a dose-dependent manner. Dietary supplementation with 0.5, 1 and 2 % glycine enhanced (P < 0.05) small-intestinal villus height, glycine transport (measured using Ussing chambers), mRNA levels for GLYT1, and anti-oxidative capacity (indicated by increased concentrations of reduced glutathione and a decreased ratio of oxidized glutathione to reduced glutathione). These novel results indicate, for the first time, that glycine is a nutritionally essential amino acid for maximal protein accretion in milk-fed piglets. The findings not only enhance understanding of protein nutrition, but also have important implications for designing improved formulas to feed human infants, particularly low birth weight and preterm infants.     

Dietary supplementation with Chinese herbal powder enhances ileal digestibilities and serum concentrations of amino acids in young pigs

This study was designed to determine the effect of ultra-fine Chinese herbal powder as a dietary additive on serum concentrations and apparent ileal digestibilities (AID) of amino acids (AA) in young pigs. In Experiment 1, 60 Duroc x Landrace x Yorkshire piglets weaned at 21 days of age were randomly assigned to one of three treatments, representing supplementation with 0 or 2 g/kg of the powder, or 0.2 g/kg of colistin (an antibiotic) to corn- and soybean meal-based diets (n = 20 per group). Blood samples from five piglets per group were collected on days 7, 14, and 28 to determine serum AA concentrations. In Experiment 2, 12 barrows with an average initial body weight of 7.64 kg were randomly assigned to one of the three dietary treatments, followed by surgical placement of a simple T-cannula at the terminal ileum. All of the diets contained 0.1% titanium oxide as a digestibility marker. The samples of terminal ileal digesta were collected on day 7 for determining AID of AA. Results show that dietary supplementation with the herbal powder increased (P < 0.05) serum concentrations and AID of most AA by 10-50% and 10-16%, respectively. As an indicator of improved intestinal function, AID values of calcium were also enhanced in piglets supplemented with the herbal powder. Dietary supplementation of colistin increased serum concentrations and AID values of some AA by 8-44% and 10-15%, respectively, in comparison with the non-supplemented group. These novel findings demonstrate that the herbal powder can enhance the digestibility of dietary protein and the intestinal absorption of AA into the systemic circulation in post-weaning pigs, therefore providing a new mechanism for its growth- and immunity-promoting efficacy.     

Effects of enteral glutamine on gut mucosal protein synthesis in healthy humans receiving glucocorticoids

In hypercatabolic patients, the beneficial effects of glutamine on gut mucosa could be partly due to a stimulation of protein synthesis. The fractional synthesis rate (FSR) of gut mucosal protein was measured in four groups of healthy volunteers treated with glucocorticoids for 2 days. Two groups were studied in the postabsorptive state while receiving glutamine or a nitrogen equivalent (control) and two groups in the fed state with or without glutamine, using a 5-h intravenous infusion of [(13)C]leucine, [(2)H(5)]phenylalanine, and cortisone. After nutrient and tracer infusion, duodenal biopsies were taken. In the postabsorptive state, FSR of gut mucosal protein were 87 and 76%/day in the control group and 130% (P = 0.058 vs. control) and 104% (P = 0.17 vs. control)/day in the glutamine group, with leucine and phenylalanine as tracers, respectively. During feeding, FSR did not increase and no significant difference was observed between glutamine and control groups. Overall, FSR of the four groups were two- to threefold higher than those obtained previously in healthy humans, suggesting that glucocorticoids may increase gut mucosal protein synthesis. However, in this situation, a moderate enteral glutamine supply failed to demonstrate a significant effect on gut mucosal protein synthesis in the postabsorptive state and during feeding.     

Enteral glutamine stimulates protein synthesis and decreases ubiquitin mRNA level in human gut mucosa

Effects of glutamine on whole body and intestinal protein synthesis and on intestinal proteolysis were assessed in humans. Two groups of healthy volunteers received in a random order enteral glutamine (0.8 mmol.kg body wt(-1)x h(-1)) compared either to saline or isonitrogenous amino acids. Intravenous [2H5]phenylalanine and [13C]leucine were simultaneously infused. After gas chromatography-mass spectrometry analysis, whole body protein turnover was estimated from traced plasma amino acid fluxes and the fractional synthesis rate (FSR) of gut mucosal protein was calculated from protein and intracellular phenylalanine and leucine enrichments in duodenal biopsies. mRNA levels for ubiquitin, cathepsin D, and m-calpain were analyzed in biopsies by RT-PCR. Glutamine significantly increased mucosal protein FSR compared with saline. Glutamine and amino acids had similar effects on FSR. The mRNA level for ubiquitin was significantly decreased after glutamine infusion compared with saline and amino acids, whereas cathepsin D and m-calpain mRNA levels were not affected. Enteral glutamine stimulates mucosal protein synthesis and may attenuate ubiquitin-dependent proteolysis and thus improve protein balance in human gut.     

Nutrient-intake-level-dependent regulation of intestinal development in newborn intrauterine growth-restricted piglets via glucagon-like peptide-2

The objective of the present study was to investigate the intestinal development of newborn intrauterine growth-restricted (IUGR) piglets subjected to normal nutrient intake (NNI) or restricted nutrient intake (RNI). Newborn normal birth weight (NBW) and IUGR piglets were allotted to NNI or RNI levels for 4 weeks from day 8 postnatal. IUGR piglets receiving NNI had similar growth performance compared with that of NBW piglets. Small intestine length and villous height were greater in IUGR piglets fed the NNI than that of piglets fed the RNI. Lactase activity was increased in piglets fed the NNI compared with piglets fed the RNI. Absorptive function, represented by active glucose transport by the Ussing chamber method and messenger RNA (mRNA) expressions of two main intestinal glucose transporters, Na⁺-dependent glucose transporter 1 (SGLT1) and glucose transporter 2 (GLUT2), were greater in IUGR piglets fed the NNI compared with piglets fed the RNI regimen. The apoptotic process, characterized by caspase-3 activity (a sign of activated apoptotic cells) and mRNA expressions of p53 (pro-apoptotic), bcl-2-like protein 4 (Bax) (pro-apoptotic) and B-cell lymphoma-2 (Bcl-2) (anti-apoptotic), were improved in IUGR piglets fed the NNI regimen. To test the hypothesis that improvements in intestinal development of IUGR piglets fed NNI might be mediated through circulating glucagon-like peptide-2 (GLP-2), GLP-2 was injected subcutaneously to IUGR piglets fed the RNI from day 8 to day 15 postnatal. Although the intestinal development of IUGR piglets fed the RNI regimen was suppressed compared with those fed the NNI regimen, an exogenous injection of GLP-2 was able to bring intestinal development to similar levels as NNI-fed IUGR piglets. Collectively, our results demonstrate that IUGR neonates that have NNI levels could improve intestinal function via the regulation of GLP-2.     

刺五加提取物对早期断奶仔猪肠道微生物多态性的影响

选用21日龄断奶的三元杂交仔猪60头,随机分为3个处理,处理1饲喂添加0.1%刺五加提取物日粮,处理2饲喂添加0.02%硫酸粘杆菌素日粮,处理3饲喂基础日粮。分别于添加后第7、14和28 d从各处理随机取5头试猪,处死后无菌采集空肠、回肠和盲肠内容物,采用体外培养计数法和PCR/DGGE技术,测定其中乳酸杆菌和大肠杆菌的数量及细菌菌群的变化。结果表明,第7 d时,提取物组回肠内容物大肠杆菌数量显著低于对照组;各肠段内容物乳酸杆菌数量均显著高于其它2组。第14 d时,提取物组各肠段内容物大肠杆菌数量均显著低于其它2组;空肠和回肠内容物乳酸杆菌数量显著高于其它2组,且盲肠内容物乳酸杆菌数量显著高于对照组。第28 d时,提取物组空肠和回肠内容物大肠杆菌数量显著低于其它2组,盲肠内容物大肠杆菌数量也显著低于对照组;回肠内容物乳酸杆菌数量显著高于其它2组。各时间点提取物组盲肠内容物细菌DGGE条带数较对照组多,第28 d时空肠内容物细菌DGGE条带数比对照组多;3个处理间各肠段内容物DGGE图谱间的相似性均达56.9%以上。提示刺五加提取物有助于提高肠道内容物乳酸杆菌的数量,抑制大肠杆菌增殖,显著增加肠道微生物的多样性,这可能是其防治断奶仔猪腹泻、促进生长的机理之一。     

Changes in the inhibitory responses to electrical field stimulation of intestinal smooth muscle from Trichinella spiralis infected rats

Functional motor changes and morphological alterations have been associated with intestinal inflammation. The aim of this work was to study functional motor changes in inflamed and non-inflamed intestinal segments of Trichinella spiralis infected rats. Thickness of muscle layers and cell infiltration during infection were also evaluated. Segments of rat jejunum and ileum were placed in organ bath and relaxations of the longitudinal muscle in response to electrical field stimulation (EFS) were recorded. During the post-infection (PI) period EFS-induced relaxations in ileum were decreased. Maximal decreases in relaxation were found on day 14-23 PI for ileum, whereas non significant changes were observed in jejunal samples throughout the experimental period. The sensitivity of the EFS-induced relaxations to the NO synthase inhibitor Nω-nitro-l-arginine (L-NNA) and to the soluble guanylate cyclase inhibitor oxadiazolo-quinoxalin-1-one (ODQ) was decreased on day 14 PI for jejunum, whereas in the ileum it lasted from day 14-23 PI. The sensitivity of EFS-induced relaxations to apamin (a small conductance calcium activated potassium channel blocker) disappeared between day 6-23 PI for both jejunum and ileum. In contrast, the sensitivity of the EFS-induced relaxations to the K⁺ channel blockers tetraethylamonium (TEA) and tetrapenthylammonium (TPEA) chloride was similar for healthy tissue and for tissue obtained form infected animals. Distribution and density of NADPH-diaphorase positive neurons was similar in tissue obtained form healthy and infected animals. In conclusion, intestinal inflammation induces functional and structural changes in both worm-free and worm-positive intestinal segments. Increased muscle thickness was similar for both inflamed and noninflamed segments but the most prominent functional changes i.e. a long-lasting decrease of EFS-induced relaxation was found in non-inflamed ileal segments.     

Effects of pre-weaning housing in a multi-suckling system on performance and carbohydrate absorption of relatively light and heavy piglets around weaning

The low feed intake and stress associated with abrupt weaning in conventional pig farming often result in poor post-weaning performance, which is related to impaired intestinal function. We investigated effects of housing conditions before weaning on performance around weaning of relatively light and heavy piglets. Before weaning, piglets were housed either with five sows and their litters in a multi-suckling (MS) system or in pens with individually housed sows in farrowing crates (FC). After weaning at 4 weeks of age (day 0), 16 groups of four piglets (two light and two heavy litter-mates) were housed under equal conditions in enriched pens. Mannitol (day −5 and day 5) and galactose (day 5) were orally administered as markers for gastrointestinal carbohydrate absorption, and after 20 min a blood sample was taken (sugar absorption test). In addition, BW, feed intake and faecal consistency as an indicator for diarrhoea, were assessed frequently during 2 weeks post-weaning. Pre-weaning housing, weight class and their interaction did not affect post-weaning faecal consistency scores. Weight gain over 2 weeks did not differ between pre-weaning housing treatments, but MS piglets gained more (0.67±0.12 kg) than FC piglets (0.39±0.16 kg) between days 2 and 5 post-weaning, P=0.02), particularly in the ‘heavy’ weight class (interaction, P=0.04), whereas feed intake was similar for both treatments. This indicates a better utilisation of the ingested feed of the MS piglets compared with the FC piglets in the early post-weaning period. Pre-weaning mannitol concentrations were unaffected by pre-weaning housing, weight class and their interaction. On day 5 post-weaning, however, MS piglets had a lower plasma concentration of mannitol (320 v. 592 nmol/ml, SEM=132, P=0.04) and galactose (91 v. 157 nmol/ml, SEM=20, P=0.04) than FC piglets, regardless of weight class. In conclusion, MS and FC piglets differed in aspects of post-weaning gastrointestinal carbohydrate absorption and in weight gain between days 2 and 5 after weaning, but pre-weaning housing did not affect feed intake, weight gain and measures of faecal consistency over the first 2 weeks after weaning.