Influence of abomasal carbohydrates on small intestinal sodium-dependent glucose cotransporter activity and abundance in steers

Most animals adapt readily to increased supplies of carbohydrate in the intestinal lumen by increasing enzymes for degradation and increasing glucose transporter activity. However, the extent of upregulation of Na+-dependent glucose cotransporter 1 (SGLT1) activity and content in response to increased delivery of carbohydrate to the small intestinal lumen of ruminants is unclear. Therefore, an experiment was conducted to determine the effect of glucose and starch hydrolysate on the activity and abundance of SGLT1 in the small intestine of steers. In a randomized complete block design, 40 crossbred beef steers (243+/-2 kg BW) were fed 0.163 Mcal of ME/(kg BW0.75(d; W), 0.215 Mcal of ME/(kg BW0.75 x d; 2M), or 0.163 Mcal ME/(kg BW0.75 x d) and infused for 35 d into the rumen (R) or abomasum (A) with 12.6 g/(kg BW0.75 x d) of starch hydrolysate (S) or into the abomasum with 14.4 g/(kg BW0.75 x d) of glucose (G). Steers were slaughtered, and brush-border membrane vesicles were prepared from the small intestinal samples obtained from five equidistant sites along the intestine. Maltase activity in vesicles and homogenates differed with intestinal sampling site (quadratic, P < 0.001). Steers on the AG treatment yielded a greater intestinal maltase activity (38 nmol glucose x mg protein(-1) x min(-1)) compared with the AS, RS, W, or 2M treatments (34, 26, 23, and 23 nmol glucose x mg protein(-1) x min(-1) respectively [SEM = 3; P = 0.02]). Sodium-dependent glucose uptake averaged 18.4+/-3.94 pmol glucose/(mg protein x s) and was not affected by treatment, but uptake decreased distally along the intestine (P < 0.001). There was no effect of treatment on SGLT1 protein abundance, but SGLT1 protein abundance increased linearly from the duodenum to the ileum (P = 0.05). The inverse relationship between glucose uptake and SGLT1 abundance suggests that the regulation of brush border Na+-dependent glucose transport capacity is complex, involving factors other than the presence of luminal carbohydrate.     

Effect of dietary phytic acid on performance and nutrient uptake in the small intestine of piglets

An experiment was conducted with piglets to determine the effect of dietary phytic acid supplementation on performance, electrophysiological properties of jejunum mounted in Ussing chambers, sodium-dependent glucose transporter 1 (SGLT1) protein expression in jejunum, and plasma glucose and Na concentrations. Sixteen piglets with an average initial BW of 7.40 ± 0.36 kg were randomly assigned to 2 experimental diets with 8 piglets per diet. The diets were casein-cornstarch-based and were either unsupplemented or supplemented with 2% phytic acid (as Na phytate). The basal diet was formulated to meet the recommendation of NRC (1998) for energy, AA, minerals, and vitamins for piglets. The experiment lasted for 21 d, and at the end, BW gain and feed consumption were determined, and blood samples were collected for determination of plasma glucose and Na concentrations. The piglets were then euthanized to determine jejunal electrophysiological properties (transmural potential difference and short-circuit current) and SGLT1 protein expression. Phytic acid supplementation reduced ADG (P = 0.002), ADFI (P = 0.017), and G:F (P = 0.001) from 316.1 to 198.2 g, 437.4 to 360.3 g, and 0.721 to 0.539 g/g, respectively. Phytic acid supplementation also tended to reduce (P = 0.088) potential difference (-3.80 vs. -2.23 mV) and reduced (P = 0.023) short-circuit current from 8.07 to 0.1 μA/cm(2). However, phytic acid supplementation did not affect SGLT1 protein, and blood plasma glucose and Na concentrations. In conclusion, dietary phytic acid reduced growth performance and transmural short-circuit current in the jejunum of piglets. The reduced transmural short-circuit current in the jejunum by phytic acid implies reduced active Na transport in the jejunum by the phytic acid. Therefore, it seems that dietary phytic acid reduces growth performance of pigs partly through reduced capacity of the small intestine to absorb Na.     

Body weight of newborn and suckling piglets affects their intestinal gene expression

Modern hyperprolific sows must deal with large litters (16–20 piglets) which reduce piglet birthweight with a concomitant increase in the proportion of small and intrauterine growth retarded piglets. However, larger litters do not only have a greater variation of piglet weights, but also a greater variation in colostrum and milk consumption within the litter. To further understand the impact that body weight has on piglets, the present study aimed to evaluate the degree of physiological weakness of the smallest piglets at birth and during the suckling period (20 d) compared to their middle-weight littermates through their jejunal gene expression. At birth, light piglets showed a downregulation of genes related to immune response (FAXDC2, HSPB1, PPARGC1α), antioxidant enzymes (SOD2m), digestive enzymes (ANPEP, IDO1, SI), and nutrient transporter (SLC39A4) (P < 0.05) but also a tendency for a higher mRNA expression of GBP1 (inflammatory regulator) and HSD11β1 (stress hormone) genes compared to their heavier littermates (P < 0.10). Excluding HSD11β1 gene, all these intestinal gene expression differences initially observed at birth between light and middle-weight piglets were stabilized at the end of the suckling period, when others appeared. Genes involved in barrier function (CLDN1), pro-inflammatory response (CXCL2, IL6, IDO1), and stress hormone signaling (HSD11β1) over-expressed compared to their middle-weight littermates (P < 0.05). In conclusion, at birth and at the end of suckling period, light body weight piglets seem to have a compromised gene expression and therefore impaired nutrient absorption, immune and stress responses compared to their heavier littermates.     

Gut ecology, feed digestion and performance in weaned piglets fed liquid diets

Gut environment and microflora, digestibility, and performance were studied in weaned piglets in Central Vietnam fed a dry control diet (CO), a naturally fermented liquid diet (FE), and a liquid diet with inclusion of rice distiller's residue (RDR). Digesta samples were collected at the start (day 0) and at the end of experiment (day 42). Diet FE had a lower pH than diet RDR, contained more organic acids, had the lowest counts of E. coli and total coliforms (P < 0.05), and the highest counts of lactic acid bacteria (LAB) (P < 0.05). Piglets fed diets FE and RDR had lower pH (P < 0.05), and higher concentrations of organic acids in the stomach, ileum and mid-colon (P < 0.05) than piglets fed diet CO. Counts of LAB in stomach and ileum were higher in animals fed diets FE and RDR than CO (P < 0.05), while the number of E. coli and total coliforms along the gastrointestinal tract was reduced. The ileal digestibility of crude protein and organic matter was improved in piglets fed diet RDR (P < 0.05) compared with piglets fed diet CO. Piglets fed diet RDR had a higher weight gain (P < 0.05) and a better feed utilization (P < 0.05) than piglets fed the other diets. The present findings support the contention that fermented diets and/or fermented feedstuffs can be used for dietary manipulation to improve gut health and animal performance.     

Low-protein diets supplemented with glutamic acid or aspartic acid ameliorate intestinal damage in weaned piglets challenged with hydrogen peroxide

Glutamic acid (Glu) and aspartic acid (Asp) are acidic amino acids with regulatory roles in nutrition, energy metabolism, and oxidative stress. This study aimed to evaluate the effects of low-protein diets supplemented with Glu and Asp on the intestinal barrier function and energy metabolism in weaned piglets challenged with hydrogen peroxide (H₂O₂). Forty piglets were randomly divided into 5 groups: NC, PC, PGA, PG, and PA (n = 8 for each group). Pigs in the NC and PC groups were fed a low-protein diet, while pigs in the PGA, PG, or PA groups were fed the low-protein diet supplemented with 2.0% Glu +1.0% Asp, 2.0% Glu, or 1.0% Asp, respectively. On day 8 and 11, pigs in the NC group were intraperitoneally injected with saline (1 mL/kg BW), while pigs in the other groups were intraperitoneally administered 10% H₂O₂ (1 mL/kg BW). On day 14, all pigs were sacrificed to collect jejunum and ileum following the blood sample collection in the morning. Notably, low-protein diets supplemented with Glu or Asp ameliorated the intestinal oxidative stress response in H₂O₂-challenged piglets by decreasing intestinal expression of genes (P < 0.05) (e.g., manganese superoxide dismutase [MnSOD], glutathione peroxidase [Gpx]-1, and Gpx-4) encoding oxidative stress-associated proteins, reducing the serum concentration of diamine oxidase (P < 0.05), and inhibiting apoptosis of the intestinal epithelium. Glu and Asp supplementation attenuated the upregulated expression of energy metabolism-associated genes (such as hexokinase and carnitine palmitoyltransferase-1) and the H₂O₂-induced activation of acetyl-coenzyme A carboxylase (ACC) in the jejunum and adenosine monophosphate-activated protein kinase–acetyl-ACC signaling in the ileum. Dietary Glu and Asp also ameliorated intestinal barrier damage as indicated by restored intestinal histology and morphology. In conclusion, low-protein diets supplemented with Glu and Asp protected against oxidative stress-induced intestinal dysfunction in piglets, suggesting that this approach could be used as a nutritional regulatory protectant against oxidative stress.     

Efficacy of bentonite clay in ameliorating aflatoxicosis in piglets fed aflatoxin contaminated diets

The efficacy of locally produced bentonite was evaluated with respect to ameliorating the adverse effects of aflatoxins (AF) in piglets fed AF contaminated diets. Forty eight piglets were randomly assigned to one of four treatments: 1) 0 g of bentonite and 0 μg AF/kg feed (control); 2) 4 g of bentonite plus 200 μg AF/kg feed (AF + Bento 4); 3) 5 g of bentonite plus 200 μg AF/kg feed (AF + Bento 5) and 4) 0 g of bentonite plus 200 μg AF/kg feed (AFA). Piglets in the AFA treatment had lower overall average daily weight gain (ADG), feed conversion efficiency, albumin (ALB) and total protein (TP) compared to the control diet, while mean serum leukocyte and enzyme activities (glutamic-oxalacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT), gamma glutamyltransferase (GGT), alkaline phosphate (ALP) and lactic dehydrogenase (LDH)) were significant increased. The inclusion of bentonite at 0.4% or 0.5% in the AF contaminated diet restored the lower performance, feed efficiency and abnormal blood profiles of the piglets given AF and no differences between 0.4 and 0.5% inclusion of bentonite. The findings in the present study provide critically needed confirmation that bentonite has the ability to reduce the adverse effects of AF.     

Nutrient and energy retention in weaned Iberian piglets fed diets with different protein concentrations

Fifty-eight purebred castrated male Iberian (IB) piglets (initial BW 9.9 ± 0.1 kg) were used in an experiment to determine the effect of dietary protein content (PC) and feeding level (FL) on the rates of BW gain, whole body protein deposition (PD), and energy utilization between 10 and 25 kg of BW using the serial slaughter method. Treatments followed a 4 × 2 factorial arrangement with 4 PC (201, 176, 149, and 123 g of CP/kg of DM) and 2 FL (0.95 and 0.70 × ad libitum) and 6 or 7 piglets per combination of treatments. All diets were formulated to have an optimal AA pattern. Six piglets were slaughtered at the start of the trial to estimate initial body composition. The experimental pigs were individually housed in an environmentally controlled room (27 ± 2°C) until they reached 25 kg of BW, when they were slaughtered and analyzed for body composition. Positive linear effects of dietary PC on ADG, G:F, and gain:ME intake were observed (P < 0.001). Piglets fed at the highest FL showed greater ADG, G:F, and gain:ME intake (P < 0.001). An average increase was estimated to be 38.0 g of gain/MJ of ME intake. Protein deposition increased linearly from 35.6 to 50.9 g/d with increasing dietary PC (P < 0.001). A daily increase was estimated to be 0.35 g of PD/g of CP intake. Although the maximal genetic potential for PD of the IB piglet was not attained, a maximal value of 59.9 g/d for whole-body PD was achieved when the diet provided 201 g of CP/kg of DM and was fed at 0.95 × ad libitum. Piglets on the highest FL deposited on average 39% more body protein (P < 0.001) than restricted piglets. An average value of 4.39 g increase in PD/MJ of ME intake was obtained for diets containing 201 and 176 g of CP/kg of DM. Maintenance energy requirements and net efficiency of utilization of ME for growth, calculated by linear regression of ME intake on body retained energy, were 427 kJ/kg of BW(0.75)·d(-1) and 0.552, respectively. The corresponding partial efficiencies of utilization of ME for protein and fat deposition were 0.378 and 0.672, respectively, considerably less than the accepted values for conventional pig breeds. Practical diets of the young IB piglet should contain at least 201 g of ideal CP/kg of DM.     

Characterisation of glucose transporter (GLUT) gene expression in broiler chickens

1. Glucose transporter (GLUT) proteins, one of which is the major insulin-responsive transporter GLUT4, play a crucial role in cellular glucose uptake and glucose homeostasis in mammals. The aim of this study was to identify the extent of mRNA expression of GLUT1, GLUT2, GLUT3 and GLUT8 in chickens intrinsically lacking GLUT4. 2. GLUT1 mRNA was detected in most tissues of 3-week-old broiler chickens, with the highest expression measured in brain and adipose tissue. GLUT2 was expressed only in the liver and kidney. GLUT3 was highly expressed in the brain. GLUT8 was expressed ubiquitously, with expression in kidney and adipose tissue relatively higher than that of other tissues. 3. Expression levels of GLUT isoforms 1, 3 and 8 in skeletal muscle tissue were very low compared to the other tissues tested. 4. [3H]Cytochalasin B binding assays on tissue from 3-week-old chickens showed that the number of cytochalasin B binding sites in skeletal muscle plasma membranes was higher than in liver plasma membranes. These results suggest that GLUT proteins and/or GLUT-like proteins that bind cytochalasin B are expressed in chicken skeletal muscles. 5. It is proposed that GLUT expression and glucose transport in chicken tissues are regulated in a manner different from that in mammals.     

Physiological aspects and ileal gene expression profile of early-weaned piglets fed a low threonine diet

High dietary threonine extraction by the digestive tract suggests that threonine contributes to maintain gut physiology. The aims of this study were to investigate both the physiological disturbances and the molecular events caused by an inadequate dietary threonine supply to the ileum of piglets. We compared paracellular permeability and gene expression, using porcine cDNA microarrays, of the ileum of piglets weaned at 7 days of age fed either a low (LT; n = 7) or a control (C; n = 7) well balanced threonine diet for 2 weeks. At slaughter, the ileal paracellular permeability, measured by FD4 flux in Ussing chambers, increased in piglets fed a LT diet compared with C piglets (P = 0.017). Furthermore, 170 genes had their expression significantly modified in the ileum of the LT piglets: 64 were down regulated and 106 were up regulated. These genes are involved in immune response, apoptosis, energy metabolism, cell migration, epithelial permeability, RNA processing or protein translation. In conclusion, dietary threonine deficiency induced alteration of the ileal barrier and the ileum seems to respond by increasing its metabolic activity.     

Effect of dipeptide on intestinal peptide transporter 1 gene expression: An evaluation using primary cultured chicken intestinal epithelial cells

Peptide transporter 1 (PepT1) is a transporter responsible for absorbing dipeptide and tripeptide in enterocytes and is upregulated by dipeptide in mammals. It has not been certain whether intestinal PepT1 expression is responsive to dipeptides in chickens because of the lack of in vitro study using the cultured enterocytes. This study established a primary culture model of chicken intestinal epithelial cells (IECs) in two-dimensional monolayer culture using collagen gel by which the response of chicken PepT1 gene expression to dipeptide stimuli was evaluated. The cultured chicken IECs showed the epithelial-like morphology attached in a patch-manner and exhibited positive expression of cytokeratin and epithelial cadherin, specific marker proteins of epithelial cells. Moreover, the chicken IECs exhibited the gene expression of intestinal cell type-specific marker, villin1, mucin 2, and chromogranin A, suggesting that the cultured IECs were composed of enterocytes as well as goblet and enteroendocrine cells. PepT1 gene expression was significantly upregulated by synthetic dipeptide, glycyl-l-glutamine, in the cultured IECs. From the results, we herein suggested that dipeptide is a factor upregulating PepT1 gene expression in chicken IECs.     

Inclusion of linseed and linseed expeller meal in piglet diets affects intestinal gene expression profiles

Linseed as a feed ingredient contains a number of constituents, such as mucilage, gel forming polysaccharides, structural carbohydrates and ω-3 fatty acids, which could have functional properties in relation to maintaining and supporting gastro-intestinal health in post weaning piglets. Intestinal gene expression was studied in weanling piglets fed diets containing either or not linseed or linseed expeller meal. Piglets were either or not orally challenged with an enterotoxigenic strain of E. coli K88. Pairwise comparisons identified several mRNAs expressed significantly different, in particular between treatments C− (control, not challenged) and LS− (linseed, not challenged) and LS+ (linseed, challenged) and LSM+ (linseed expeller meal, challenged). The intestinal micro-array technique is a promising tool to study the relationship between nutrition and feeding and gut tissue responses under defined conditions.     

Small intestinal morphology in weaned piglets fed a diet containing spray-dried porcine plasma

The hypothesis tested in this study was that the reported beneficial effects of spray-dried porcine plasma (SDPP) on piglet post-weaning performance and health are associated with a trophic effect on small intestinal mucosa. At 24 days of age, the piglets of seven sows were assigned to one of three treatment groups. One group continued to be suckled. The other two groups were weaned and offered a diet containing either 15 per cent SDPP or casein. From each treatment group, one piglet was anaesthetised and samples were taken from the small intestinal wall at 26, 28 and 31 days of age. There were no significant effects of SDPP versus casein on villus length. On average, there was less mitotic activity in the SDPP -fed piglets than in those fed casein on days 4 and 7 after weaning. As less mitotic activity leads to less immature enterocytes, this may provide a mechanism for the reported beneficial effects of SDPP on performance and health.     

Growth, nutrient utilization and intestinal morphology of pigs fed high-fiber diets

Two trials (24 and 48 pigs; 9.7 kg initial body weight) were conducted to determine the effects of dietary fiber on growth, nutrient utilization and intestinal morphology of young pigs. The four diets fed were: basal corn-soybean meal (B), 15% oat hulls (OH), 15% soybean hulls (SH), and 20% alfalfa meal (AM). Fiber source did not have major effects on performance in a 35-d feeding trial. Balance trials (7-d duration) were conducted 32 d (Trial 1) or 6 d (Trial 2) after completion of the feeding trials. Feed intakes were equalized at 8.7% (Trial 1) or 10.3% (Trial 2) of initial body weight (kg.75). All fiber sources decreased apparent digestibilities of N, energy and dry matter (P less than .05) with no effect on N retention. Apparent digestibilities of neutral and acid detergent fiber, cellulose, and hemicellulose were reduced by OH and AM (P less than .01), but not by SH. Fiber sources did not affect apparent Ca, P, Zn or Mn absorption or retention, or Mg absorption, but decrease Mg retention (P less than .05). Apparent Na absorption was decreased by OH and increased by AM (P less than .05) but was unaffected by SH. All fiber sources increased K intake, but only SH and AM increased apparent K absorption (P less than .05). Fiber sources did not affect Na or K retention. The OH increased Cu intake and balance (P less than .05). All fiber sources increased Fe intake, but only SH and AM increased (P less than .05) Fe balance. Villus shape and surface morphology in jejunum and ileum examined by scanning electron microscopy (Trial 1 only) appeared to be independent of diet. However, jejunum villus morphologies of two pigs fed AM were characterized by loss of epithelial cells and microvilli at the villus apex, and ileum villi were blunted and frequently folded in one pig fed SH. Fiber sources at the levels included in a corn-soybean meal diet fed in this study had only a minimal impact on performance and utilization of minerals and N and intestinal structure, although apparent energy utilization was decreased.     

高锌日粮对断奶仔猪肠道黏膜免疫及黏膜上皮形态的影响

本试验旨在研究长期饲喂不同锌源的高锌日粮对断奶应激仔猪肠道黏膜免疫及黏膜上皮形态的影响。选用临床检查健康的(26±2)日龄"杜×长×大"三元杂交断奶仔猪60头,按体质量和性别随机分成3组,每组20头,分别饲喂基础日粮、基础日粮+3 000 mg.kg-1氧化锌和基础日粮+500 mg.kg-1蛋氨酸锌。试验期70 d。于试验结束时,每组选取5头仔猪放血致死,分别取十二指肠近端、空肠近端1/4处、空肠远端1/4处和回肠中段,用于测定肠黏膜绒毛高度、绒毛宽度、隐窝深度,小肠上皮间淋巴细胞、杯状细胞数量,粘液层厚度及肠道粘液中IgA的含量。结果显示,在断奶后0～42 d,添加高锌日粮组仔猪的体重和日增重显著或极显著高于对照组仔猪(P0.05或P0.01),而在断奶后42～70 d,对照组仔猪日增重显著高于添加高锌日粮组仔猪(P0.05);两高锌组仔猪小肠黏膜结构有明显的损伤,表现为绒毛高度下降,隐窝变深,肠黏膜上皮细胞萎缩,肠道粘液层厚度变薄;上皮间淋巴细胞数、杯状细胞数和肠道黏液中IgA水平都显著或极显著低于对照组(P0.05或P0.01)。高锌日粮长期暴露引起断奶仔猪锌中毒,改变了肠道黏膜上皮结构的完整性,并降低了仔猪生长性能及肠道黏膜免疫功能。     

Dietary glutamine supplementation enhances expression of ZO-1 and occludin and promotes intestinal development in Min piglets

Forty-eight Min piglets at 7 days of age were randomly divided into two groups which were fed with 0% and 0.8% glutamine, respectively. Supplementation with 0.8% l-glutamine, the average daily gain (ADG) were significantly increased, and the concentrations of glutamine, glutamate, arginine and citrulline in plasma were significantly improved (P?P?P?P?相似文献   

Small intestinal morphology and disaccharidase activities in early-weaned piglets fed a diet containing spray-dried porcine plasma

The purpose of this study was to test whether dietary spray-dried porcine plasma (SDPP) in early-weaned piglets prevents small intestinal villus atrophy by trophic or protective activity. Fifty-four weaned, 18-day-old piglets were used to determine the effect of dietary SDPP on small intestinal villus length, crypt depth, enterocyt mitotic activity and brush border enzyme activities during the first week after weaning. The piglets were offered a diet containing either 8% SDPP or 8% casein. At 2 and 7 days after weaning, piglets were anaesthetized to provide samples of the small intestinal wall and killed immediately afterwards. There were no differences in daily gain and daily feed intake between the two dietary treatments. At day 2 after weaning, all piglets showed a marked reduction in villus height when compared with baseline values. In all piglets, small intestinal enterocyte mitotic activity had decreased by day 2 and was increased again on day 7. There were no significant effects of dietary SDPP on small intestinal villus length, crypt depth and enterocyt mitotic activity. This indicates that SDPP has no trophic effect on the small intestinal mucosa and that it does not protect against the damaging effect on the small intestinal villi that is associated with the process of weaning. There was no effect of SDPP on lactase-, sucrase- or maltase-specific activities that are a measure of the digestive function of the small intestine. It can be concluded that SDPP versus casein has no effect on small intestinal morphology and disaccharidase activities in early weaned piglets kept under low infection pressure.     

Effects of age and diet on small intestinal structure and function in gnotobiotic piglets

The effects of age and dietary change on the structure and function of piglet small intestine were investigated in gnotobiotic pigs. The small intestinal mucosa was damaged when gnotobiotic pigs were weaned on to a pelleted meal diet; villus height, crypt cell production rate, and activities of brush border enzymes were reduced. Small intestinal damage was associated with reduced weight gain over a three week period; diarrhoea was not observed. The continuous consumption of meal appeared to perpetuate the intestinal damage for three weeks, although evidence of intestinal repair, as indicated by an increased crypt cell production rate, was present three weeks after weaning. Antibodies to soya antigen were detected in serum after weaning and the intestinal damage could have been caused by antibody-mediated immune reactions to soya proteins. Villi of milk fed gnotobiotic pigs shortened significantly with age.