Sucrase Specific Activity Research Articles

The effects of creep feed composition and form and nursery diet complexity on small intestinal morphology and jejunal mucosa-specific enzyme activities after weaning in pigs.

Fifty-six litters from first-parity sows standardized to 12 piglets were used to determine the effects of creep feed composition and form and the provision of low- or high-complexity nursery diets on the evolution of small intestinal histomorphology and jejunal mucosa-specific enzyme activities postweaning. At 5 d of age, litters (initial bodyweight [BW] 2.31 ± 0.61 kg) were assigned to one of four creep feeding regimens (n = 14): 1) commercial creep feed (COM), 2) liquid milk replacer (LMR), 3) pelleted milk replacer (PMR), or 4) no creep feed (NO). At weaning (21 d of age), six pigs per litter were provided a HIGH- (contained highly digestible animal proteins) or LOW- (contained corn and soybean meal as main protein sources) complexity nursery diet (n = 7). At 21, 28, and 59 d of age, two pigs per pen (one castrated male and one female) were euthanized, and ileal and jejunal segments for histomorphological measurements and jejunal mucosal scrapings were collected to determine specific mucosa enzyme activities. At weaning, pigs provided COM had a greater ileal absorptive capacity (M) than LMR or NO, which were not different (14.1 vs. 10.4 and 10.5 ± 0.9 μm2; P < 0.05); PMR was intermediate. On days 28 and 59, M was not different among pigs regardless of creep feed treatments. Pigs fed LOW had reduced jejunal villus height (VH; P < 0.001) and M (P < 0.001) on day 28 vs. day 21. The VH and M were not different for pigs fed HIGH or LOW by the end of the nursery period. For all dietary treatments except COM-HIGH and COM-LOW, jejunal mucosal maltase-specific activity was not different between days 21 and 28 of age but greater on day 59 (P < 0.05). For pigs that received COM-HIGH, maltase-specific activity was not different between days 21 and 28 but greater on day 59 than day 28 (P < 0.05). For pigs that received COM-LOW, maltase-specific activity was not different between days 21, 28, and 59. Regardless of creep or nursery treatment, sucrase-specific activity was the greatest on day 59, followed by days 21 and 28 (P < 0.001), and lactase-specific activity was greater on day 21 than on days 28 and 59 (P < 0.001), which were not different. Therefore, pigs that provided LOW diet had greater villus atrophy and reduced M during the first week after weaning vs. pigs that provided HIGH, regardless of creep feeding regimen, but were able to recover by the end of the nursery period.

Formula Feeding Predisposes Gut to NSAID-Induced Small Intestinal Injury.

Breast feeding protects infants from many diseases, including necrotizing enterocolitis, peptic ulceration and infectious diarrhea. Conversely, maternal separation stress and Non-Steroidal Anti-Inflammatory Drugs (NSAID's) can induce intestinal injury and bleeding. This study aimed to evaluate in suckling rats if maternal separation/formula feeding leads to increased intestinal sensitivity to indomethacin (indo)-induced intestinal injury and to look at potential mechanisms involved. Nine-day-old rats were dam-fed or separated/trained to formula-feed for 6 days prior to indo administration (5 mg/kg/day) or saline (control) for 3 days. Intestinal bleeding and injury were assessed by measuring luminal and Fecal Hemoglobin (Hob) and jejunal histology. Maturation of the intestine was assessed by measuring luminal bile acids, jejunal sucrase, serum corticosterone, and mRNA expression of ileal Apical Sodium-Dependent Bile Acid Transporter (ASBT). At 17 days, formula-fed indo-treated pups had a 2-fold increase in luminal Hb compared to formula-fed control pups and had evidence of morphological injury to the small intestinal mucosa as observed at the light microscopic level, whereas indo had no effect on dam-fed littermates. In addition, formula-fed rats had significant increases in luminal bile acid, sucrase specific activity, serum corticosterone, and expression of ASBT mRNA compared to dam-fed rats. Maternal separation stress may cause early intestinal maturational changes induced by corticosteroid release, including increased epithelial exposure to bile acids. These maturational changes may have a sensitizing rather than protective effect against indo-induced injury in the new-born.

Effects of dietary supplementation of a zinc oxide product encapsulated with lipid on growth performance, intestinal morphology, and digestive enzyme activities in weanling pigs

The present experiment was performed to investigate the effects of a lipid-encapsulated ZnO product (Shield Zn) on growth, intestinal morphology, and digestive enzyme activities in (Yorkshire×Landrace)×Duroc piglets. A total of 408 21-day-old weanling pigs were allotted by sex and body weight to 12 pens, with 34 animals per pen, in a randomized complete block design. The animals were fed a ZnO-free basal nursery diet supplemented with 125mg ZnO (100mg Zn)/kg (ZnO-100), 3125mg ZnO/kg (ZnO-2500), or 139mg of lipid-encapsulated Shield Zn (100mg Zn)/kg (Shield Zn-100) for 14 days, after which 24 animals were killed for examination of intestinal morphology and digestive enzyme activities. The average daily gain of the Shield Zn-100 group (207g/d) was greater (P<0.01) than that of the ZnO-100 group (184g/d), but was less (P<0.01) than that of the ZnO-2500 group (235g/d). The average daily feed intake was less in the Shield Zn-100 (326g/d) than in the Zn-2500 group (367g/d; P<0.01), not being different between the former and the ZnO-100 group (309g/d; P=0.23). However, the gain:feed ratio was not influenced by the treatment. The fecal consistency (diarrhea) score subjectively measured by a 3-notch integer scale was greater (P<0.01) in the Shield Zn-100 (1.30) and ZnO-100 (1.31) groups vs. ZnO-2500 group (1.06). Hepatic and circulating Zn concentrations were less (P<0.01) in the Shield Zn-100 and ZnO-100 groups vs. ZnO-2500, not being different between the former two groups. The villus height, crypt depth and villus height:crypt depth ratio in the duodenum, jejunum, and ileum as well as specific activities of sucrase, maltase, leucine aminopeptidase in these intestinal regions and amylase and trypsin activities in the pancreas were not influenced by the dietary treatment. In conclusion, the present results indicate that supplementation of Shield Zn at a physiological level is superior to that of native ZnO at the same level in supporting weight gain of weanling pigs, but that the former is inferior to pharmacological ZnO in the growth-enhancing and diarrhea-suppressing effects.

Effects of a lipid-encapsulated zinc oxide supplement on growth performance and intestinal morphology and digestive enzyme activities in weanling pigs.

This study compared the effects of varying lipid content and dietary concentration of a lipid-encapsulated (LE) ZnO product to those of native ZnO and thereby to find insights into optimal lipid coating and dosage of the Zn supplement. A total of 192 21-d-old weanling pigs were allotted to 48 pens, after which each six pens received a ZnO-free basal diet supplemented with 125 ppm ZnO (100 ppm Zn; BASAL), 2,500 ppm Zn as native ZnO (HIGH), or 100 or 200 ppm Zn as LE ZnO (LE-100 or LE-250) containing 8%, 10%, or 12% lipid [LE-8%, LE-10%, or LE-12%, respectively; 2 × 3 factorial arrangement within the LE-ZnO diets (LE-ALL)] for 14 d. Forty pigs were killed at the end for histological and biochemical examinations. None of ADG, ADFI, gain:feed, and fecal consistency score differed between the LE-ALL and either of the BASAL and HIGH groups. Hepatic and serum Zn concentrations were greater (p <0.05) in the HIGH vs. LE-ALL group, but did not differ between LE-ALL and BASAL, between LE-100 and -250, or among LE-8%, -10%, and -12% groups. Villus height (VH), crypt depth (CD), and the VH:CD ratio in the duodenum, jejunum, and ileum did not differ between the LE-ALL and either of the BASAL and HIGH groups, except for a greater CD in the duodenum in the LE-ALL vs. HIGH group. Additionally, VH and CD in the duodenum and VH:CD in the jejunum were greater in the LE-250 vs. LE-100 group. Specific activities of sucrase, maltase, and leucine aminopeptidase in these intestinal regions and those of amylase and trypsin in the pancreas were not influenced by the lipid content or dietary concentration of LE ZnO and also did not differ between the LE-ALL and either of the BASAL and HIGH groups, except for a greater pancreatic amylase activity in the former vs. HIGH group. In conclusion, the present results indicate that the LE ZnO, regardless of its lipid percentage or supplementation level examined in this study, has no significant effect on growth performance, fecal consistency, or digestive enzyme activities of weanling pigs under the experimental conditions.

Ursodeoxycholic acid promotes intestinal adaptation in a cat model of short bowel syndrome

The aim of this study was to assess the effect of ursodeoxycholic acid (UDCA) on the morphological and functional adaptive response of the jejunal remnant after massive intestinal resection in a cat model of short bowel syndrome (SBS). UDCA was administered to animals at a daily oral dose of 15 mg/kg for 6 weeks following a 85% jejunoileal resection. Resection alone caused extensive hyperplasia of jejunal mucosa, as evidenced by a significant increase in the weight of jejunal mucosa per unit length as well as by significant increases in DNA and protein concentration but no change in the protein/DNA ratio. Morphometric analysis using microscopy revealed no changes in jejunal mucosa thickness, jejunal crypt depth, villus height and villus surface area, although villus thickness was increased. The specific activities of jejunal sucrase and alkaline phosphatase were unaffected. UDCA treatment of resected animals, using doses that caused no toxicity, as evidenced by the absence of serum biochemistry abnormalities and histopathology, did not induce, compared to resection alone, any changes in mucosal cellularity and did not affect villus morphometry. On the other hand, UDCA administration increased crypt depth and, also, induced a profound increase in the specific activity of sucrase. UDCA improved diarrhoea, a core SBS symptom, reflected in a considerably reduced frequency of defaecation and improved form and texture of faeces. It is concluded that UDCA administration may enhance the natural adaptive response of the intestinal remnant following massive jejunoileal resection and may, thus, be beneficial in SBS treatment.

A melon pulp concentrate rich in superoxide dismutase reduces stress proteins along the gastrointestinal tract of pigs

Objective A melon ( Cucumis melo LC.) pulp concentrate (MPC) rich in superoxide dismutase (SOD) activity was tested for its ability to decrease stress protein expressions along the gastrointestinal tract in a swine model. Methods Pig sextuplets weaned at 21 d of age were selected from among six litters ( n = 36). After a 2-d fasting period, the pigs were fed at similar levels of intake of the control, MPC1, and MPC2 diets, which provided 0, 12.5, and 50 IU of added SOD per kilogram of food, respectively. One triplet of pigs per litter was slaughtered at 7 d and the second triplet at 14 d after weaning. SOD, catalase, and digestive enzymes were determined enzymatically and stress protein expressions by western blotting. Results Plasma SOD increased with MPC dose at day 14 ( P < 0.05). Mucosal weights in the proximal and mid small intestine were lower at day 14 ( P < 0.05), cecum tissue weight was greater ( P < 0.05), and sucrase-specific activity in mid and distal small intestine mucosa was lower ( P = 0.05) in the MPC2 group than in the control group. MPC supplementation essentially decreased ( P < 0.05 to P < 0.001) stress proteins in the stomach (all), the mid small intestine (heat-shock protein-27, neuronal nitric oxide synthase) and the colon (heat-shock protein-70, neuronal nitric oxide synthase). Conclusion A SOD-rich MPC provided at the dose of 50 IU/kg of food for up to 12 d was effective in lowering the level of stress proteins along the gastrointestinal tract of pigs after weaning.

Colonic GLP‐2 is not Sufficient to Promote Jejunal Adaptation in a PN‐Dependent Rat Model of Human Short Bowel Syndrome

Bowel resection may lead to short bowel syndrome (SBS), which often requires parenteral nutrition (PN) due to inadequate intestinal adaptation. The objective of this study was to determine the time course of adaptation and proglucagon system responses after bowel resection in a PN-dependent rat model of SBS. Rats underwent jugular catheter placement and a 60% jejunoileal resection + cecectomy with jejunoileal anastomosis or transection control surgery. Rats were maintained exclusively with PN and killed at 4 hours to 12 days. A nonsurgical group served as baseline. Bowel growth and digestive capacity were assessed by mucosal mass, protein, DNA, histology, and sucrase activity. Plasma insulin-like growth factor I (IGF-I) and bioactive glucagon-like peptide 2 (GLP-2) were measured by radioimmunoassay. Jejunum cellularity changed significantly over time with resection but not transection, peaking at days 3-4 and declining by day 12. Jejunum sucrase-specific activity decreased significantly with time after resection and transection. Colon crypt depth increased over time with resection but not transection, peaking at days 7-12. Plasma bioactive GLP-2 and colon proglucagon levels peaked from days 4-7 after resection and then approached baseline. Plasma IGF-I increased with resection through day 12. Jejunum and colon GLP-2 receptor RNAs peaked by day 1 and then declined below baseline. After bowel resection resulting in SBS in the rat, peak proglucagon, plasma GLP-2, and GLP-2 receptor levels are insufficient to promote jejunal adaptation. The colon adapts with resection, expresses proglucagon, and should be preserved when possible in massive intestinal resection.

Effects of Xylanase on Growth and Gut Development of Broiler Chickens Given a Wheat-based Diet

To study the working mechanisms for non-starch polysaccharidases to improve the growth performance of broiler chickens, a 21-day feeding trial was conducted. Two dietary treatments were included: 1) wheat diet (the control); 2) wheat+xylanase diet (xylanase, Allzyme PT, Alltech, Kentucky, USA). There were 8 replicates with 8 birds each for each treatment and the experimental diets were given to birds from hatch. Feed intake and body weight were measured on days 7 and 21. At the same ages, samples were taken for the determination of selected groups of luminal and mucosa-associated bacteria, mucosal morphology, brush-border membrane (BBM) bound enzyme activity and ileal nutrient digestibility. The xylanase supplement increased (p 0.05) by xylanase. Up to day 7, xylanase increased the counts of C. perfringens in the ileum and total anaerobic bacteria (TAB) in the caeca (p 0.05) by the supplement but crypt depth at the same site was reduced at day 7. Also, xylanase tended to increase the concentration of BBM protein (p = 0.09) and the specific activity of sucrase (p = 0.07) at day 21. (Key Words : Xylanase, Growth Performance, Nutrient Digestibility, Gut Microflora, Intestinal Mucosal Morphology, Specific Activity of BBM Bound Enzymes)

Sodium tungstate decreases sucrase and Na+/d-glucose cotransporter in the jejunum of diabetic rats

Sodium tungstate reduces glycemia and reverts the diabetic phenotype in several induced and genetic animal models of diabetes. Oral administration of this compound has recently emerged as an effective treatment for diabetes. Here we examined the effects of 30 days of oral administration of tungstate on disaccharidase and Na+/D-glucose cotransporter (SGLT1) activity in the jejunum of control and streptozotocin-induced diabetic rats. Diabetes increased sucrase-specific activity in the jejunal mucosa but did not affect the activity of lactase, maltase, or trehalase. The abundance and the maximal rate of transport of SGLT1 in isolated brush-border membrane vesicles also increased. Tungstate decreased sucrase activity and normalized SGLT1 expression and activity in the jejunum of diabetic rats. Furthermore, tungstate did not change the affinity of SGLT1 for d-glucose and had no effect on the diffusional component. In control animals, tungstate had no effect on disaccharidases or SGLT1 expression. Northern blot analysis showed that the amount of specific SGLT1 mRNA was the same in the jejunum from all experimental groups, thereby indicating that changes in SGLT1 abundance are due to posttranscriptional mechanisms. We conclude that the antidiabetic effect of tungstate is partly due to normalization of the activity of sucrase and SGLT1 in the brush-border membrane of enterocytes.

Neutral detergent-soluble fiber improves gut barrier function in twenty-five-day-old weaned rabbits1

The effect of neutral detergent-soluble fiber level on gut barrier function and intestinal microbiota was examined in weaned rabbits. A control diet (AH) containing 103 g of neutral detergent-soluble fiber/ kg of DM included alfalfa hay as main source of fiber. Another diet (B-AP) was formulated by replacing half of the alfalfa hay with a mixture of beet and apple pulp resulting in 131 g of soluble fiber/kg of DM. A third diet (OH) was obtained by substituting half of the alfalfa hay with a mix of oat hulls and a soybean protein concentrate and contained 79 g of soluble fiber/kg of DM. Rabbits weaned at 25 d and slaughtered at 35 d were used to determine ileal digestibility, jejunal morphology, sucrase activity, lamina propria lymphocytes, and intestinal microbiota. Suckling 35-d-old rabbits were used to assess mucosa morphology. Mortality (from weaning to 63 d of age) was also determined. Villous height of the jejunal mucosa increased with soluble fiber (P = 0.001). Rabbits fed with the greatest level of soluble fiber (BA-P diet) showed the highest villous height/ crypt depth ratio (8.14; P = 0.001), sucrase specific activity (8,671 mumol of glucose/g of protein; P = 0.019), and the greatest ileal starch digestibility (96.8%; P = 0.002). The opposite effects were observed in rabbits fed decreased levels of soluble fiber (AH and OH diets; 4.70, 5,848 mumol of glucose/g of protein, as average, respectively). The lowest ileal starch digestibility was detected for animals fed OH diet (93.2%). Suckling rabbits of the same age showed a lower villous height/crypt depth ratio (6.70) compared with the B-AP diet group, but this ratio was higher than the AH or OH diet groups. Lower levels of soluble fiber tended (P = 0.074) to increase the cellular immune response (CD8+ lymphocytes). Diet affected IL-2 production (CD25+, P = 0.029; CD5+CD25+, P = 0.057), with no clear relationship between soluble fiber and IL-2. The intestinal microbiota biodiversity was not affected by diets (P >/= 0.38). Rabbits fed the B-AP and AH diets had a reduced cecal frequency of detection compatible with Campylobacter spp. (20.3 vs. 37.8, P = 0.074), and Clostridium perfringens (4.3 vs. 17.6%, P = 0.047), compared with the OH diet group. Moreover, the mortality rates decreased from 14.4 (OH diet) to 5.1% (B-AP diet) with the increased presence of soluble fiber in the diet. In conclusion, increased levels of dietary soluble fiber improve mucosal integrity and functionality.

Chronic psychological stress alters epithelial cell turn-over in rat ileum

Dysregulated epithelial cell kinetics associated with mucosal barrier dysfunction may be involved in certain intestinal disorders. We previously showed that chronic psychological stress, in the form of repetitive sessions of water avoidance stress (WAS), has a major detrimental impact on ileal barrier function. We hypothesized that these changes were related to a disturbance in enterocyte kinetics. Rats were submitted to WAS (1 h/day) for 5 or 10 days. As previously shown, permeability to macromolecules was enhanced in rats stressed for 5 and 10 days compared with controls. WAS induced a decrease in crypt depth at day 5 associated with an increased number of apoptotic cells. Cell proliferation was significantly increased at days 5 and 10. Villus height and the specific activity of sucrase were significantly reduced at day 10. We concluded that WAS induces a disturbance of epithelial cell kinetics, with the pattern depending on the duration of the stress period. These findings help to explain the mechanism underlying altered epithelial barrier function resulting from exposure to chronic psychological stress.

Vagal afferents are essential for maximal resection-induced intestinal adaptive growth in orally fed rats

Small bowel resection stimulates intestinal adaptive growth by a neuroendocrine process thought to involve both sympathetic and parasympathetic innervation and enterotrophic hormones such as glucagon-like peptide-2 (GLP-2). We investigated whether capsaicin-sensitive vagal afferent neurons are essential for maximal resection-induced intestinal growth. Rats received systemic or perivagal capsaicin or ganglionectomy before 70% midjejunoileal resection or transection and were fed orally or by total parenteral nutrition (TPN) for 7 days after surgery. Growth of residual bowel was assessed by changes in mucosal mass, protein, DNA, and histology. Both systemic and perivagal capsaicin significantly attenuated by 48-100% resection-induced increases in ileal mucosal mass, protein, and DNA in rats fed orally. Villus height was significantly reduced in resected rats given capsaicin compared with vehicle. Sucrase specific activity in jejunal mucosa was not significantly different; ileal mucosal sucrase specific activity was significantly increased by resection in capsaicin-treated rats. Capsaicin did not alter the 57% increase in ileal proglucagon mRNA or the 150% increase in plasma concentration of bioactive GLP-2 resulting from resection in orally fed rats. Ablation of spinal/splanchnic innervation by ganglionectomy failed to attenuate resection-induced adaptive growth. In TPN rats, capsaicin did not attenuate resection-induced mucosal growth. We conclude that vagal afferents are not essential for GLP-2 secretion when the ileum has direct contact with luminal nutrients after resection. In summary, vagal afferent neurons are essential for maximal resection-induced intestinal adaptation through a mechanism that appears to involve stimulation by luminal nutrients.

Phenotypic plasticity in response to low quality diet in the South American omnivorous rodent Akodon azarae (Rodentia: Sigmodontinae)

We studied the responses in the omnivorous rodent A. azarae submitted to a low quality diet at morphological, physiological and biochemical levels. At short term, a decrease in body mass occurred. A later increase in food consumption constituted a strategy that allowed a temporal recovery of physical condition. However, hyperphagia appeared not to be enough to maintain physical condition after 30 days of low quality diet consumption. At the morphological level, an increase in length (9%) of the anterior portion of the gut occurred, the part of the gut where digestion and absorption take place. A decrease in small intestine weight could be related with the long-term impairment of body condition. Inhibition of sucrase specific activity in small intestine would indicate a down-regulation of sucrase-isomaltase complex. Total maltase specific activity in small intestine was not affected suggesting an up-regulation of sucrase-independent maltase specific activity. A down-regulation of protease specific activity in small intestine occurred in response to low quality diet. The specific activity of disaccharidases in caecum and large intestine was down-regulated. The strategies and constraints at different levels of A. azarae upon low quality diet are discussed.

Phenotypic flexibility of digestive morphology and physiology of the South American omnivorous rodent Akodon azarae (Rodentia: Sigmodontinae)

We have determined the occurrence of responses at different levels (morphological, physiological and biochemical) in the omnivorous rodent Akodon azarae upon cold acclimation (15 °C). A short-term enhancement in food consumption appeared to account for the maintenance of both mass and body composition. At the morphological level, the main response was an increase in the dimensions of small intestine, which constitutes the section of the gut where absorption and secretion take place. An increase in sucrase specific activity was only found in small intestine. Sucrose independent maltase activity was very low since 99.8% of total maltase activity was due to sucrase–isomaltase (SI) complex. Protease specific activities were not affected. The fact that resting metabolic rates determined at 15 and 23 °C were similar in cold acclimated animals suggests a change in lower critical temperature. In conclusion, our results show that A. azarae exhibits different strategies to support cold environment that could lead to an enhancement in digestion and absorption efficiency. Furthermore, this work suggests that low temperature is an independent cue of other environmental factors to trigger the strategies allowing the maintenance of body condition in A. azarae.

Spermine-induced maturation in wistar rat intestine: a cytokine-dependent mechanism.

Polyamines are of great importance in biologic processes such as cell proliferation and differentiation. The ingestion of spermidine or spermine by suckling rats induces the precocious maturation of the small intestine. In a previous article, the authors hypothesized that this phenomenon could be mediated by interleukins. This work was performed to examine the role of IL-1, IL-2, and tumor necrosis factor (TNF)- alpha in the spermine-induced maturation of the small intestine. Wistar suckling rats were treated with spermine, FR167653 (inhibitor of IL-1beta/TNF-alpha production), IL-1beta/TNF-alpha neutralizing antibodies, lipopolysaccharide, or IL-2. Intestinal disaccharidase-specific activities, polyamine content, and IL-2 plasma concentration were analyzed. Comparisons were made with untreated control animals. Spermine-induced maturation of the small intestine was decreased by FR167653 but not by the neutralizing antibodies. Lipopolysaccharide injection induced an increase in disaccharidase-specific activity. IL-2 induced a decrease of the intestinal lactase-specific activity. Spermine administration led to a similar decrease of lactase activity and to an increase of IL-2 plasma concentration. The authors conclude that IL-1beta and TNF-alpha are involved in the spermine effects on maltase- and sucrase-specific activities and suggest that IL-2 is involved in the spermine-induced decrease of lactase activity.

Effect of inclusion of sunflower hulls in the diet on performance, disaccharidase activity in the small intestine and caecal traits of growing rabbits

AbstractA basal diet was formulated to meet the nutrient requirements of growing rabbits. Another diet was formulated by substituting 152 g/kg of the basal diet with sunflower hulls (SH diet). One hundred and sixty-eight weaned 30-day-old rabbits were given these diets and finishing performance was recorded. Eighty animals were used to study the effect of SH inclusion on caecal fermentation traits at two ages (5 and 35 days after weaning) and disaccharidase activity in the small intestine at 35 days after weaning. Inclusion of SH in the diet reduced growth rate by proportionately 0·056 in the first 2 weeks after weaning (P 0 ×001), but had no effect from 14 to 65 days after weaning. Accordingly, daily gain was lower by a factor of 0·035 over the whole finishing period (P 0×01). There was no effect of treatment on food intake during the 14 days after weaning, but SH inclusion tended to increase it from this time onwards ( +0·026; P = 0 ×06) and over the whole finishing period ( + 0·018; P = 0 ×09). This effect was parallel to a 0·09 proportional decrease in the weight of caecal contents (P 0 ×01) observed in animals of 2 kg live weight. Food efficiency was lower by a factor of 0·05 (P 0×001) in all the periods considered when SH was included in the diet. Mortality rate (6%) was not affected by treatment nor was caecal pH or caecal concentrations of volatile fatty acids and ammonia nitrogen either at 5 days (5×75, 72×7 mmol/l and 16×6 mmol/l, respectively) or at 35 days after weaning (5×70, 74×3 mmol/l and 9 ×7 5 mmol/l, respectively). Inclusion of SH increased sucrase specific activity at the ileum by a factor of 0·47 (P 0×01) but had no effect on maltase specific activity at the jejunum or ileum or on sucrase specific activity at the jejunum. In conclusion, SH included at moderate levels (150 g/kg) in the diet reduced accumulation of digesta in the caecum, which increased voluntary food intake but impaired growth rate and food efficiency. Inclusion of SH did not affect caecal fermentation or mortality.

Diet-related adaptation of the small intestine at weaning in pigs is functional rather than structural.

Incidence of diarrhea at weaning in commercial pigs is an important problem, and diet is thought to be a predisposing factor. The aim of this study was to determine the impact of switching from milk-based to cereal-based diets on the morphology and function of the small intestine of piglets using a model of delayed weaning to isolate the influence of the diet from that of environmental and social factors. Forty-five piglets received a milk-based diet for 5 weeks after weaning. Thirty piglets were then switched from milk-based to wheat- or barley-based diets, mimicking the dietary change that occurs at weaning. The last 15 piglets remained on the milk-based diet. Piglets were killed 4 days after the dietary switch. Jejunal mucosa morphometry and enzyme activities were measured. Ussing chambers were used to measure intestinal permeability to macromolecules, basal electrical properties, glucose absorption, and induced chloride-secretion. Alkaline phosphatase- and sucrase-specific activities were higher in both groups of cereal-fed piglets than in milk-fed piglets. Dipeptidylpeptidase IV activity was higher in wheat-fed piglets than in the other groups. Na + -dependent glucose absorption was 1.7-fold higher in cereals-fed piglets than in milk-fed piglets. Serotonin-induced and vasoactive intestinal polypeptide-induced chloride secretion was doubled in cereals-fed piglets. Dietary transition did not influence the other parameters. These results indicate that switching from milk to cereals increased some mucosal enzyme activities, intestinal Na + -dependent glucose absorption, and response to secretagogues. This supports the hypothesis that dietary factors could initiate diarrhea in the presence of other aggravating factors, such as pathogens or environmental stress.

Estimation of apparent L-amino acid diffusion in porcine jejunal enterocyte brush border membrane vesicles

There is an overlap of carrier-mediated L-amino acid transport and apparent simple diffusion when measured in intestinal brush border membrane vesicles. Using L-threonine and L-glutamine as representative amino acids, this study was undertaken to estimate apparent simple diffusion of L-amino acids and to establish the effective dosage of HgCl2 for completely blocking carrier-mediated L-amino acid transport in porcine jejunal enterocyte brush border membrane vesicles. Jejunal mucosa was scraped from three pigs weighing 26 kg. Enterocyte brush border membrane vesicles, with an average enrichment of 24-fold in sucrase specific activity, were prepared by Mg2+-precipitation and differential centrifugation. In vitro uptake was measured by the fast filtration manual procedure. HgCl2 blocked the carrier-mediated initial transport of L-threonine and L-glutamine under Na+-gradient condition in a dose-dependent manner. At the minimal concentration of 0.165 mmol HgCl2 mg-1 protein, carrier-mediated L-threonine and L-glutamine transport was completely inhibited. The apparent L-threonine and L-glutamine diffusion was estimated to be 8.6±0.7 and 12.4±1.0 % of the total uptake at the substrate concentrations of 5 mM (L-threonine) and 50 mM (L-glutamine). Therefore, the treatment of porcine brush border membrane vesicles with a minimum of 0.165 mmol HgCl2 mg-1 protein completely blocks carrier-mediated L-amino acid transport and enables the direct estimation of apparent L-amino acid diffusion in enterocyte brush border membrane vesicles.

Pancreatic Exocrine Secretions as a Source of Luminal Polyamines in Pigs

The goal of the present study was twofold: (1) to detect the possible storage of dietary polyamines (PAs) in various tissues and (2) to investigate the role of dietary PAs in the differentiation of the pig intestinal epithelium. A first experimental series was designed to assess the accumulation of either milk PAs (mostly spermidine) or orally administered spermine (SPM) in piglet red blood cells (RBCs) and plasma, a preliminary stage in their distribution to growing and storage organs. Though PA concentrations of piglet RBCs and plasma were generally significantly higher than their sow counterparts, our experimental conditions failed to demonstrate that this increase could stem from ingested PAs. A second experimental series dealt with the determination of disaccharidase specific activities in proximal and distal parts of piglet gut on the 26th and 29th days after birth (preweaning time). In agreement with observations made previously on rat pups, we observed an increase in maltase specific activity (SA) at the end of the suckling period (the observed increase in sucrase SA was not significant). However, orally administered SPM did not affect this activity. Compared to the constant protein concentrations observed in both parts of the gut, the pancreatic protein content decreased sharply between the 26th and 29th postnatal days. At the same time pancreatic concentrations of spermidine (SPD) also decreased, suggesting that some pancreatic PAs were released as the organ secreted its proteins. In accordance with this hypothesis, we recorded SPM and SPD in pancreatic juice. The increases in PA concentrations seemed to follow the protein secretion pattern (i.e. PA concentrations reached a maximal value when the protein concentration was highest). The presence of PAs in pancreatic juice could be indicative of a control mechanism exerted by the pancreas on PA-induced growth and differentiation of porcine intestinal epithelium.

Pancreatic exocrine secretions as a source of luminal polyamines in pigs

The goal of the present study was twofold: (1) to detect the possible storage of dietary polyamines (PAs) in various tissues and (2) to investigate the role of dietary PAs in the differentiation of the pig intestinal epithelium. A first experimental series was designed to assess the accumulation of either milk PAs (mostly spermidine) or orally administered spermine (SPM) in piglet red blood cells (RBCs) and plasma, a preliminary stage in their distribution to growing and storage organs. Though PA concentrations of piglet RBCs and plasma were generally significantly higher than their sow counterparts, our experimental conditions failed to demonstrate that this increase could stem from ingested PAs. A second experimental series dealt with the determination of disaccharidase specific activities in proximal and distal parts of piglet gut on the 26th and 29th days after birth (preweaning time). In agreement with observations made previously on rat pups, we observed an increase in maltase specific activity (SA) at the end of the suckling period (the observed increase in sucrase SA was not significant). However, orally administered SPM did not affect this activity. Compared to the constant protein concentrations observed in both parts of the gut, the pancreatic protein content decreased sharply between the 26th and 29th postnatal days. At the same time pancreatic concentrations of spermidine (SPD) also decreased, suggesting that some pancreatic PAs were released as the organ secreted its proteins. In accordance with this hypothesis, we recorded SPM and SPD in pancreatic juice. The increases in PA concentrations seemed to follow the protein secretion pattern (i.e. PA concentrations reached a maximal value when the protein concentration was highest). The presence of PAs in pancreatic juice could be indicative of a control mechanism exerted by the pancreas on PA-induced growth and differentiation of porcine intestinal epithelium.