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Alginate oligosaccharide (AOS), a depolymerisation product of alginic acid polysaccharides of seaweed by alginate lyases, holds great potential as a novel feed supplement in swine production. This study conducted two trials to evaluate the effects of AOS supplementation on the growth performance, antioxidant capacity, serum hormone levels and intestinal digestion-absorption function in weaned pigs. In trial 1, 200 weaned pigs were allotted to four groups and fed a basal diet (control group) or a basal diet containing 50, 100 and 200 mg/kg AOS, respectively. Supplementation with 100 or 200 mg/kg AOS for 2 weeks significantly increased ( P P P P + /glucose co-transporter 1 ( SGLT1 ) and divalent metal transporter 1 ( DMT1 ) transcriptions in the jejunal mucosa. Altogether, dietary AOS inclusion can stimulate weaned pig growth, validating AOS as a valid feed supplement in the pig industry.

This study was conducted to investigate the effects of in ovo feeding (IOF) of Arg solution on the hatchability, growth performance, gastrointestinal hormones, serum AA, activities of digestive enzymes, and mRNA expressions of sensing receptors and nutrient transporters in the jejunum of posthatch broilers. One thousand two hundred embryonated eggs with similar weight were randomly allocated to 5 groups consisting of 8 replicates of 40 eggs each. The 5 treatments were arranged as a noninjected control, a diluent-injected (0.75% NaCl solution) group, and Arg solution-injected groups with 0.5%, 1.0%, and 2.0% Arg, all dissolved in diluent. At 17.5 d of incubation, 0.6 mL of IOF solution was injected into the amniotic fluid of each egg of the injected groups. Results showed the hatchability of the 2% Arg group was lower (linear, = 0.025) than that of the other groups, and the BW of 21-d-old broilers increased (linear, = 0.008; quadratic, = 0.003) with increasing IOF concentration of Arg. The ADFI (linear, = 0.005; quadratic, = 0.001) and ADG (linear, = 0.010; quadratic, = 0.004) increased during d 1 to 21 with increasing IOF concentration of Arg. For 7- and 21-d-old broilers, the weights of digestive organs increased (linear, < 0.05) with increasing IOF concentrations of Arg; the greatest values were observed in the 1% Arg group. For 21-d-old broilers, IOF of the 1% Arg solution increased ( < 0.05) the concentrations of ghrelin and glucagon-like peptide 2; the activities of digestive enzymes, alkaline phosphatase, maltase, and sucrase in the jejunum; and the concentrations of serum AA of Val, Met, Ile, Leu, Arg, and Pro compared with those of the noninjected control and diluent-injected group. In ovo feeding of the 1% Arg solution also increased ( < 0.05) the mRNA expressions of jejunal sensing receptors of taste receptor type 1 members 1 and 3; the G protein-coupled receptor, class C, group 6, subtype A; nutrient transporters of solute carrier family 7, members 4, 6, and 7; sodium-glucose transporter 1; and fatty acid-binding protein 1. In conclusion, the 1% Arg solution was the appropriate injection level. In ovo feeding of the 1% Arg solution did not affect the hatchability but facilitated the release of gastrointestinal hormones, increasing the digestive and absorptive capacity and finally improving the growth performance of 21-d-old broilers. Therefore, IOF of the appropriate Arg solution could be an effective technology for regulating early nutrition supply and subsequent growth development in the poultry industry.

A glucansucrase encoding gene was cloned into pET-28a(+) vector and expression in Escherichia coli BL21(DE3). An about 160 kDa recombinant glucansucrase was purified with a yield of 50.73% and a 4.02-fold increase in activity. The 1464 amino acid residue enzyme belongs to the GH70 subfamily and shares 90% similarity with Leuconostoc sp. glucansucrase. The optimal temperature and pH were 30 °C and pH 5.5, and 80% of activity was retained after incubation at 10–30 °C and pH 5–7. Enzyme activity was strongly activated by Ca2+ and Mn2+ and inhibited by various metal ions and chemical agents, and a high affinity for sucrose (Km = 11.6 mM, Vmax = 8.1 mmol/(mL·min)). Circular dichroism (CD) and Raman spectra collectively indicated a high proportion of random coil structure.

BACKGROUND Prebiotics selectively stimulate the growth of beneficial bacteria within the gastrointestinal tract, and have been investigated in human and animal studies for their capacity to improve intestinal health. OBJECTIVE We investigated the prebiotics fructo-oligosaccharide (FOS), galacto-oligosaccharide (GOS), and mannan-oligosaccharide (MOS) for their potential to alleviate intestinal damage in rats. METHODS Female Dark Agouti rats (6-8 wk old, 110-150 g) were allocated to 1 of the following treatment groups (n = 8/group): saline/water, saline/FOS, saline/GOS, saline/MOS, 5-fluorouracil (5FU)/water, 5FU/FOS, 5FU/GOS, and 5FU/MOS. Rats were pretreated with either 5% GOS, MOS, or FOS or vehicle (water) from day -12 to day 0. On day 0, rats received a single intraperitoneal injection of saline or 5FU. Metabolic data were recorded daily and all rats were killed on day 3. Histopathology was quantified in hematoxylin and eosin-stained sections. Intestinal sucrase and myeloperoxidase activity were quantified by biochemical assay. Fecal SCFAs-acetic, propionic, and butyric acid-were also measured. Statistical analysis was by repeated-measures, 2-factor ANOVA or Kruskal-Wallis and Mann-Whitney U test; P

Early nutrition of pullets could determine the overall development and the performance of laying hens. With the aim to reduce the use of antibiotic growth promoters (AGPs) and to maintain the growth and development of pullets, the effect of simultaneous short-termed supplementation of AGPs (bacitracin zinc 20 mg/kg and colistin sulfate 4 mg/kg) and Bacillus subtilis (B. subtilis) DSM17299 probiotic, as well as the effect of supplementation of AGPs (bacitracin zinc 20 mg/kg and colistin sulfate 4 mg/kg) during the whole period (0~16 weeks) on the overall growth and development, intestinal health, and caecal microbiota of pullets were evaluated. In the present study, a total of 630 one-day-old Hy-Line Brown layers were randomly distributed into five equal groups: including the AGPs group (supplemented with AGPs based on basal diets for 16 weeks), the BA3 group (supplemented with AGPs and B. subtilis based on basal diets for 3 weeks), the BA6 group (for 6 weeks), the BA12 group (for 12 weeks), and the BA16 group (for 16 weeks). When compared with the AGPs group, the supplementation of AGPs + B. subtilis for the first 3 weeks could maintain overall growth performance, including the average body weight, average feed intake, average daily weight gain, and feed conversion ratio of pullets at 3, 6, 12, and 16 weeks of age (P > 0.05). Meanwhile, the characteristic growth indexes in different periods were separately measured. At 3 weeks of age, the amylase activity in ileum was elevated (P = 0.028), and the length of tibia was up to the standard in the BA3 group. At 12 weeks of age, the increased villus height (P = 0.046) of jejunum, increased villus height (P = 0.023) and ratio of villus height to crypt depth (P = 0.012) of ileum, decreased crypt depth (P = 0.002) of ileum, and elevated mRNA levels of sucrase in jejunum (P < 0.05) were all identified in the BA3 group. At 16 weeks of age, the secreted immunoglobulin A (sIgA) content in the jejunum mucosa of the BA3 group was greater than the other groups (P < 0.001). Furthermore, altered intestinal microbiota was found in the BA3 group. Specifically, decreased amounts of Alistipes, Bacteroides, Odoribacter, Dehalobacterium, and Sutterella and increased amounts of Lactobacillus, Dorea, Ruminococcus, and Oscillospira were determined (P < 0.05) in the BA3 group at week 6. Meanwhile, decreased amounts of B. fragilis and C. leptum (P < 0.05) were identified in the BA3 group at week 12, which were found to be relevant for the improvement of intestinal morphology (P < 0.05) by Pearson analysis. In conclusion, simultaneous supplementation of AGP and B. subtilis for 0~3 weeks increased the relative abundance of beneficial microbiota in caecum in 0~6 weeks, then improved the intestinal morphology by elevating populations of B. fragilis and C. leptum in 7~16 weeks, and further upregulated sucrase expression and increased sIgA content in the intestinal mucosa in 13~16 weeks.

Intestinal epithelial cells undergo rapid renewal along the crypt-villus axis (CVA), which ensures intestinal functions. Weaning stress differentially effects intestinal epithelial cell metabolism and physiological states along the CVA. Sulfur amino acids (SAA) play a key role in intestinal epithelial cell functioning. This study evaluated the effects of SAA dietary supplementation on weaning pig jejunal epithelial cells along the CVA. Sixteen Duroc × Landrace × Yorkshire piglets (6.16 ± 0.22 kg BW) were weaned at 21 d of age and were blocked by BW and gender and the randomly assigned to 1 of 2 groups fed diets consisting of low (0.53%) or high (0.85%) levels of SAA for a 7-d period. All piglets were euthanized for tissue sampling on day 7 postweaning. Jejunal epithelial cells were isolated along the CVA to yield 3 "cell fractions" (upper villus, middle villus, and crypt cells). The number of proliferating cells per crypt of piglets fed the high SAA diet was lower (P < 0.05) than that for low SAA diet. High SAA diet piglets tended to have decreased (P = 0.059) sucrase activities compared low SAA diet piglets. A high SAA diet increased (P < 0.05) total antioxidant capacity, catalase, and superoxide dismutase activities compared with a low SAA diet. mRNA expression levels of claudin-1, Slc5a1, and Slc7a9 in high SAA diet piglets were lower (P < 0.05) than for low SAA diet piglets. There were no interactions between dietary SAA and cell sections along the CVA for enzyme activities and mRNA expression in any of the weaned piglets. Protein amounts and phosphorylation levels related to Wnt/β-catenin and mechanistic targeting of rapamycin (mTOR) signaling pathways were affected by SAA in weaning piglets. These findings indicate that dietary SAA affects jejunal cell proliferation and functions in weaning piglets. There appears to be no interactions between dietary SAA and cell sections along the CVA. The effects of SAA may be partly through affecting antioxidant capacity, and Wnt/β-catenin and mTOR signaling pathway.

A 4 × 2 factorial experiment was conducted to investigate the effect of inclusion of spray-dried porcine plasma (SDPP), in lieu of meat meal, in the starter diet on performance and digestive physiology of broiler chickens between hatch and 35 d of age. Four levels of SDPP (0, 5, 10 or 20 g/kg) were included in the starter diets in lieu of meat meal on either wheat- or maize-based diets. Over the first 10 d, and throughout the 35-d experimental period, birds gained more body weight with increasing concentrations of SDPP regardless to the type of grain used. Inclusion of SDPP in the starter diet markedly improved feed per gain in the starter phase and across the 35-d study. There was no significant effect of the type of grain and its interaction with SDPP on the body weight gain and feed per gain for the two assessed periods. At d 10, the relative weight of the gizzard+proventriculus, spleen and liver increased with increasing concentrations of SDPP. At 24 d of age, the grain and SDPP inclusion significantly interacted, depressing the weight of bursa and spleen in birds that received the highest concentration of SDPP in the maize-based diet. Birds fed on the maize-based diets had higher relative weight of pancreas than those on the wheat-based diets. Increasing concentrations of SDPP in the starter diet improved the activities of maltase, sucrase and alkaline phosphatase at 24 d of age. The interaction of grain and SDPP concentration was significant for sucrase activity in birds on the wheat-based diets. Chickens on maize-based diets had higher alkaline phosphatase and maltase activities than those on wheat-based diets. Chicks that were offered SDPP-containing starter diets had longer villi, deeper crypts and lower villi/crypt than the control at 24 d of age regardless of the grain type used. Furthermore, longer villi and larger villi/crypt were found in chicken groups fed on wheat-based diets than those on maize-based diets. Chickens on maize-based diets had higher dressing percentage and relative breast weight than those on wheat-based diets at 35 d of age. It can be concluded that supplementation of starter diets with SDPP would be beneficial to the long-term growth of broiler chickens. The effect of the basal grain used in the diet is minimal.

The objective of this study was to evaluate the effect of different fiber sources on jejunal digestive and absorptive physiology in weaned piglets. One hundred weaned piglets were allotted according to body weight, gender and litter to four dietary treatments. Each treatment was replicated in 5 pens of 5 pigs each. The experimental diets contained 10% of a fiber source: wheat bran (WB), maize fiber (MF), soyabean fiber (SF), or pea fiber (PF). Piglets were fed ad libitum for 30 d. Reduced villus height and villus height-to-crypt depth ratio (P PF > MF > WB. Our study indicates that SF and PF could promote apparent faecal digestibility in piglets, but this is not accompanied by better jejunal morphology or digestive enzyme activities as compared with WB.

To test the hypothesis that a low molecular weight fraction of colostral whey could affect the morphology and barrier function of the small intestine, 30 3-d-old piglets (normal or low birth weight) were suckled (n = 5), artificially fed with milk formula (n = 5), or artificially fed with milk formula with a low molecular weight fraction of colostral whey (n = 5) until 10 d of age. The small intestine was sampled for histology (haematoxylin and eosin stain; anti-KI67 immunohistochemistry) and enzyme activities (aminopeptidase A, aminopeptidase N, dipeptidylpeptidase IV, lactase, maltase, and sucrase). In addition, intestinal permeability was evaluated via a dual sugar absorption test and via the measurement of occludin abundance. Artificially feeding of piglets reduced final BW (P < 0.001), villus height (P < 0.001), lactase (P < 0.001), and dipeptidylpeptidase IV activities (P < 0.07), whereas crypt depth (P < 0.001) was increased. No difference was observed with regard to the permeability measurements when comparing artificially fed with naturally suckling piglets. Supplementing piglets with the colostral whey fraction did not affect BW, enzyme activities, or the outcome of the dual sugar absorption test. On the contrary, the small intestines of supplemented piglets had even shorter villi (P = 0.001) than unsupplemented piglets and contained more occludin (P = 0.002). In conclusion, at 10 d of age, no differences regarding intestinal morphology and permeability measurements were observed between the 2 BW categories. In both weight categories, the colostral whey fraction affected the morphology of the small intestine but did not improve the growth performances or the in vivo permeability. These findings should be acknowledged when developing formulated milk for neonatal animals with the aim of improving the performance of low birth weight piglets.

Summary Cereal grains such as maize and wheat are used extensively in feed formulations for poultry as the primary source of carbohydrates. High cost of these grains in many developing countries necessitates the evaluation of other ingredients that are grown locally. Sweet potato is one such crop. The study was conducted as a proof of concept experiment to test the hypothesis that in the presence and absence of enzyme, sweet potato roots when included in diets of broiler chickens may affect the total metabolisable energy content of the diets which may exert certain influences on dry matter digestibility of these diets as well as impacting on production and certain gut parameters. A total of 120 chicks were raised on a commercial starter feed from day 0 to 19. On day 22, the birds were individually weighed and allocated to 96 single bird metabolism cages to conduct a 7-day classical apparent metabolisable energy (AME) assay. The test diets contained 0% and 25% sweet potato flour (SPF) with and without enzyme supplementation (Rovabio Excel AP T-flex) and replicated 24 times. AME of the control diet with and without enzyme was 14.05 and 13.91 MJ/kg whilst the AME of the SPF diets with and without enzymes were 13.45 and 13.43 MJ/kg respectively. AME of SPF was 12.08 MJ/kg. Birds fed the SPF had significantly reduced end weights (p = .002) and weight gains (p

During diabetes, structural and functional changes in the alimentary tract are known to take place resulting in an increased absorption of intestinal glucose and alterations in the activities of brush-border disaccharidases. To elucidate the effect of administrating polysaccharide fromGynura divaricata(PGD) on disaccharidase activities, the specific activities of intestinal disaccharidases, namely sucrase, maltase and lactase, were measured in streptozotocin-induced diabetic rats. Normal control and diabetic rats were treated by oral administration with PGD. Specific activities of intestinal disaccharidases were increased significantly during diabetes, and amelioration of the activities of sucrase and maltase during diabetes was clearly visible by the treatment with PGD. However, the increased activity of lactase during diabetes mellitus was remarkably alleviated by the administration of PGD only in the duodenum. Meanwhile, oral sucrose tolerance tests demonstrated that PGD alleviated the hyperglycaemia during diabetes mellitus, resulting from the amelioration in the activities of intestinal disaccharidases. The present investigation suggests that PGD exerted an anti-diabetic effect partly via inhibiting the increased intestinal disaccharidase activities of diabetic rats. This beneficial influence of administration of PGD on intestinal disaccharidases clearly indicates their helpful role in the management of diabetes.

Castrated male Iberian (n = 12) and Landrace × Large White (n = 12) pigs were used to study histological structure and enzymatic activity in the small intestine at 3 points of the productive cycle (BW = 15, 50, and 115 kg). Both strains were fed the same cereal-based diets (DE = 2,799 kcal·kg −1 , and CP = 15%) throughout the entire experimental period. Dif- ferences (P < 0.05) in histometrical variables (villus height, width and surface, crypt depth, villus height/ crypt depth relationship, mucosal thickness, muscular layer thickness, and number of goblet cells) were found among samples of small intestinal sections (duodenum, jejunum, and ileum) at the 3 productive stages studied. Also, differences (P < 0.05) in histometrical variables of small intestinal samples were found between Iberian and lean pigs at all productive stages, although these differences tended to disappear with age. Differences (P < 0.05) in enzymatic activities (lactase, sucrase, maltase, isomaltase, aminopeptidase, and alkaline phosphatase) of small intestinal samples were found be- tween the different intestinal sections at all productive stages studied. Although differences (P < 0.05) in enzy- matic activities of small intestinal samples were found between Iberian and lean pigs at all productive stages, values tended to equalize with pig age. We concluded that differences previously found in dietary nutritional utilization between Iberian and lean strains are likely not due to differences in intestinal absorption or hydro- lytic capacity.

1. The objective of the present study was to examine the effect of in ovo injection of disaccharides (DS), disaccharides and glutamine (DS + Gln) or disaccharides and β-hydroxy-β-methylbutyrate (DS + HMB) at d 23 of incubation on the development of the small intestine. 2. In DS + Gln-injected ducks, the greatest relative small intestine mass and muscularis layer thickness among 4 treatments was observed from d 25 of incubation to 7 d of age. 3. Jejunal sucrase activity in DS-injected ducks was significantly greater than in controls at hatch and on d 7. 4. In DS + HMB-treated ducks, a tendency toward slightly higher jejunal DNA concentration was observed throughout the experiment. 5. Greater body weight was found in DS + Gln and DS + HMB treated ducks in the first two weeks. However, there was no significant difference in the market weight (35 d) of ducks among the 4 treatments. 6. The results of present study suggest that administering disaccharides and Gln, or disaccharides and HMB, to the duck embryos exerted a beneficial effect on the early development of small intestine and on growth performance.

The aim of this experiment was to investigate the physiological and growth response of young turkeys (up to 8 weeks of age) to dietary replacement of soybean meal (SBM) by soy protein concentrate (PC) or protein isolate (PI). This replacement resulted in a differentiated dietary concentration of α-galactosides of over 2.5% in the SBM diet, approximately 2% with a mixture SBM and PC, 1% with a PC diet and 0.1% with a PI diet. Each treatment was applied in two ways: with lower (3.5%) or higher (5.3%) dietary crude fibre content, made by supplementation with soybean hulls. The highest and lowest body weight of turkeys was recorded both after the first and second 4-week half of the study in the PC and PI-type diets respectively. A gradual withdrawal of α-galactosides from a diet was accompanied by a decline in ileal tissue mass, ileal viscosity and activity of endogenous maltase (the latter was found to be significant at 4 weeks of age). At the same time, two-way anova revealed that an elevated level of crude fibre (HF treatment) caused an increase in ileal tissue mass (p < 0.05 after 4 weeks of feeding) as well as a decrease in activity level of intestinal sucrase and maltase. The presence of raffinose family oligosaccharides in a diet, in contrast to dietary crude fibre level, significantly affected the caecal metabolism. The rate of bacterial production of short-chain fatty acids in the caeca was distinctly diminished by dietary withdrawal of α-galactosides. In conclusion, the soy protein concentrate, in contrast to the protein isolate preparation, exerted positive effects on the turkeys' growth and gastrointestinal tract physiology and should be considered as an effective SBM substitute.

To evaluate the effects of dietary hemi- cellulose from corn on growth and metabolic measures, female pigs (n = 48; initial BW 30.8 kg) were fed di- ets containing 0 to 38.6% solvent-extracted corn germ meal for 28 d. Increasing the hemicellulose level had no impact on ADG or ADFI, but resulted in a quadratic response (P < 0.03) on G:F. To investigate physiologi- cal changes that occur with increased dietary hemicel- lulose, blood, colon contents, and tissue samples from the liver and intestine were obtained from a subset (n = 16; 8 pigs/treatment) of pigs fed the least and great- est hemicellulose levels. The abundance of phospho- adenosine monophosphate-activated protein kinase (AMPK) and the mitochondrial respiratory protein, cytochrome C oxidase II (COXII) were determined in liver, jejunum, ileum, and colon by Western blotting. The mRNA expression levels of AMPKα1, AMPKα2, PPAR coactivator 1α (PGC1-α), PPARγ2, and sirtuin 1 (Sirt1) were determined in liver and intestinal tis- sues. When compared with pigs fed the control diet, pigs fed the high hemicellulose diet had increased (P < 0.02) plasma triglycerides, but there was no differ- ence in plasma cholesterol, glucose, or insulin. Absolute and relative liver weights were decreased (P < 0.03) in pigs consuming the high hemicellulose diet. The high- fiber diet led to a tendency (P < 0.12) for decreased liver triglyceride content. In pigs fed the high hemicel- lulose diet, ileal mucosal alkaline phosphatase activity was increased (P < 0.08) and sucrase activity tended (P < 0.12) to be increased. The high hemicellulose diet had no effect on phospho-AMPK, AMPK mRNA, or colonic VFA, but in pigs consuming the high fiber diet there was a greater (P < 0.05) abundance of COXII in colon tissue. The expression of PGC1-α, PPARγ, or Sirt1 mRNA was not altered by dietary fiber in liver, jejunum, or ileum tissue. In colon tissue from pigs fed the high fiber diet there was an increase (P < 0.09) in Sirt1 mRNA and a trend (P < 0.12) toward increased of PGC1-α mRNA. These data suggest that alterations in metabolism involved in adaptation to a diet high in hemicellulose are associated with increased colonic Sirt1 mRNA and COXII expression, indicating an increased propensity for oxidative metabolism by the intestine.

The present study investigated the effect of different zinc (Zn) levels on activities of gastrointestinal digestive enzymes of growing rats. Four diets including Zn-adequate (ZA; 46 mg/kg, control), Zn-deficient (ZD; 3 mg/kg), high Zn supply (ZH; 234 mg/kg) and pair-fed in which animals received the ZA diet at restricted amounts reflecting feed intake of the ZD group were fed to rats for 5 weeks. Dietary Zn was supplemented with ZnO. The results showed that Zn deficiency resulted in decreases in body weight, while ZH supply stimulated growth. The activities of sucrase, lactase and lipase were unaffected by dietary Zn levels. Maltase activity, however, was reduced in ZD group and elevated in ZH group. Amylase and protease activities were depressed by zinc deficiency. However, rats fed the Zn-repletion diet displayed higher activity of pepsin, pancreatic amylase and protease. In particular, ZH supply did have no effect on intestinal hydrolases activities. The present study suggested that zinc deficiency impaired the activities of digestive enzymes and growth of animals. However, ZH supply might improve the digestion of nutrients via increasing activities of gastrointestinal hydrolase and probably enhanced animal health.

An experiment was conducted to investigate the effects of diets containing soybean meal (SBM), soybean protein concentrate (SPC), and soybean protein isolate (SPI) on growth performance and gut function of the young turkey. A total of 812 one-day-old male turkey poults were randomly assigned to 4 dietary treatments, with 7 pens per treatment and 29 birds per pen. The 4 experimental diets contained SBM, SBM-SPC, SPC, and SPI and were fed throughout the two 4-wk experimental periods. In each period, the diets were isonitrogenous and isocaloric and contained similar amounts of total and water-soluble nonstarch polysaccharides. The content of oligosaccharides differed among the diets and averaged 2.4, 1.9, 0.9, and 0.1% for SBM, SBM-SPC, SPC, and SPI, respectively. When compared with SBM, birds consuming the SBM-SPC and SPC diets had higher (P0.05) final BW (4.32 vs. 4.45 and 4.46 kg, respectively). Incorporation of SPI as a substitute for SBM resulted in improved (P0.05) feed utilization (from 1.76 to 1.67) but did not affect the final BW. Significant changes in cecal concentrations of short-chain fatty acids were observed and averaged 130, 103, and 89 micromol/g of digesta for the SBM, SBM-SPC, and SPC diets, respectively. This coincided with the proportional decrease in dietary oligosaccharide content (from 2.4 to 0.9%) and was further substantiated by a significant decrease in ileum weights. Feeding the SPI diet resulted in the lowest ileal and cecal tissue weights as well as the lowest cecal short-chain fatty acids concentration. There was no effect of diet on digesta pH, viscosity, and mucosal sucrase and maltase activities. Bacterial beta-glucuronidase activity was decreased (P=0.08) in the cecum (from 0.98 to 0.60 U/g) with decreased dietary oligosaccharide content. In conclusion, partial or almost complete substitution of SBM with SPC suppressed the fermentation processes in the ceca but enhanced the growth rate. Substitution of SBM with SPI significantly improved feed utilization but decreased BW of 4-wk-old turkeys with no effect on growth rate of older 8-wk-old birds.

Galacto-oligosaccharides (GOS) are non-digestible oligosaccharides with short galactosyl chain units produced by lactose fermentation which are considered as prebiotics. Only few studies have investigated the effects of GOS medium-term ingestion on the small intestinal epithelium characteristics. In this study, we evaluated the consequences of GOS ingestion on small intestinal mucosal morphology, on brush-border membrane enzyme activities and on mucin content in BALB/c mice. Mice received the experimental diets for 4 weeks and then the small intestine was collected to measure sucrase, lactase and alkaline phosphatase activities, to study the villus heights in the jejunum mucosa and to determine mucosal mucin content as well as MUC-2 and MUC-4 mRNAs expression by qRT-PCR. Our results showed that GOS has no detectable effect on the intestine villus height but increased the total protein content by twofold. Sucrase activity was significantly increased in the intestinal mucosa recovered from animals fed the GOS diet without any detectable modification of lactase and phosphatase activities. Interestingly, GOS was also able to increase sucrase activity in cultured Caco-2 cells raising the view that they likely act directly on these cells. Furthermore, GOS was found to markedly increase O-linked glycoproteins associated with the intestinal mucosa without modifying MUC-2, MUC-4 mRNAs expression. Lastly, TNF-α mRNA expression was also not modified after GOS ingestion. These results suggest that, in BALB/c mice, 4-week GOS ingestion is able to increase the small intestinal mucosa-associated mucin content and enterocyte-associated sucrase activity without modifying villus height.

（1） トチノキ種皮よりポリフェノールを熱水で抽出し，Diaion HP-20, Chromatorex ODS 1024T, そしてSephadex LH-20のカラムクロマトグラフィーで分離したF1，F2，F3のそれぞれの画分をMALDI-TOF/MSで分析した．その結果，主成分は，縮合型タンニンであり，F2で19mer, F3で23mer以上のポリマーとして存在することが明らかになった．（2） トチノキ種皮のタンニンは，単結合のBタイプの架橋に加えて，二重結合により架橋したAタイプのインターフラバン結合を多数，有していた．また，構成単位は，ガロイル基により修飾されていない（＋）-カテキン，もしくは（−）-エピカテキンであった．（3） トチノキ種皮に由来するポリフェノール成分について，糖質消化酵素に対する阻害作用を検討した．その分画成分は，α-グルコシダーゼおよびα-アミラーゼに対して強い阻害活性を示した．これらは，血糖値の急激な上昇を緩和する機能性食品素材として期待できる．

Diabetes mellitus is a most serious and chronic disease whose incidence rates are increasing with incidences of obesity and aging of the general population over the world. One therapeutic approach for decreasing postprandial hyperglycemia is to retard absorption of glucose by inhibition of alpha-glucosidase. Two bromophenols, 2,4,6-tribromophenol and 2,4-dibromophenol, were purified from the red alga Grateloupia elliptica. IC(50) values of 2,4,6-tribromophenol and 2,4-dibromophenol were 60.3 and 110.4 microM against Saccharomyces cerevisiae alpha-glucosidase, and 130.3 and 230.3 microM against Bacillus stearothermophilus alpha-glucosidase, respectively. In addition, both mildly inhibited rat-intestinal sucrase (IC(50) of 4.2 and 3.6mM) and rat-intestinal maltase (IC(50) of 5.0 and 4.8mM). Therefore, bromophenols of G. elliptica have potential as natural nutraceuticals to prevent diabetes mellitus because of their high alpha-glucosidase inhibitory activity.

SummaryThe method for disaccharidase activity assay in peroral biopsies of the human small-intestinal mucosa is described in detail. The specificity of the enzymes and the clinical conditions affectin

The aim of our study was to investigate the possible effects of the removal of different parts of the stomach (fundectomy, antrectomy, gastrectomy) on the total protein content and enzyme activity in the pancreas and the brush border of the intestinal mucosa. Twenty-four 2.5-month-old male Wistar rats were divided into four groups: sham-operated animals (SHO) and those subjected to gastrectomy (Gx), fundectomy (Fx), and antrectomy (ANT). After a six-week experiment, the rats were sacrificed, and blood was collected for further gastrin analysis in serum. Samples of the pancreas, duodenum, and jejunum (proximal part in 25% of length, middle part in 50% of length, and distal part in 75% of length) were collected to determine the total protein content and enzyme activity. The rats subjected to fundectomy, antrectomy and gastrectomy showed an increased total protein content and enzyme activity (amylase, trypsin) in pancreatic tissue. They exhibited an increase in the total protein content in the homogenates of the mucosa of the proximal, middle and distal jejunum, compared to the control, and a statistical increase in maltase activity. Compared with the control group, the rats subjected to Fx and ANT showed a decreased sucrase activity in the homogenates of the mucosa of the duodenum and of the proximal, middle and distal jejunum. In the gastrectomized rats, there was a statistically significant increase in the total protein content in the homogenates of the mucosa of the jejunum, compared to the control, while the activities of lactase and sucrase were decreased. There was a statistically significant increase in the gastrin level in all experimental groups (Fx, ANT, Gx). We suggest that surgical removal of a part of the stomach radically changes the level of hormones that determine many functions of the organism. Hormonal changes may have an impact on the pancreas and the activity of brush border enzymes. .

Necrotic enteritis caused by Clostridium perfringens has become prevalent in the European Union due to the withdrawal of antibiotics in poultry feed. In an experiment with a 2 × 2 factorial arrangement, 336 one-day-old male broiler chicks (Ross 308) were assigned to 4 groups with or without C. perfringens challenge and fed wheat-based diets supplemented with or without xylanase at 5,500 U/kg of diet. The study aimed to investigate effects of xylanase addition on growth performance as well as nutrient digestion and absorption of C. perfringens-infected broilers. Before challenge (d 0-14), xylanase-supplemented birds had greater ADG and lower feed conversion ratio (FCR; P < 0.05). During infection (d 14-21), challenge tended to decrease ADG (P = 0.063) and significantly increased FCR (P < 0.05), whereas xylanase addition greatly reduced FCR (P < 0.05). Clostridium perfringens infection decreased AME values and apparent ileal digestibility of DM of diets (P < 0.05). Xylanase supplementation increased AME values regardless of infection and apparent ileal digestibility of CP in challenged birds (P < 0.05). Activities of duodenal α-amylase and chymotrypsin and pancreatic trypsin were decreased by C. perfringens infection (P < 0.05). Xylanase supplementation elevated pancreatic chymotrypsin activity and reduced duodenal α-amylase and trypsin activities (P < 0.05). It also decreased jejunal α-amylase activity and increased pancreatic α-amylase as well as jejunal sucrase activities in uninfected birds (P < 0.05). The duodenal mRNA expression of sodium glucose cotransporter 1 (SGLT1), H(+)-dependent peptide transporter 1 (PepT1), and liver fatty acid-binding protein (L-FABP) were downregulated (P < 0.05), but ileal SGLT1 gene expression was increased by infection (P < 0.05). Xylanase addition upregulated expression of jejunal SGLT1, PepT1, and L-FABP genes as well as ileal PepT1 and L-FABP genes in challenged broilers (P < 0.05). In conclusion, xylanase supplementation of wheat-based diets improved FCR and AME in birds irrespective of C. perfringens infection and elevated apparent ileal digestibility of CP and mRNA expression of nutrient transporters in challenged birds.

Diabetes was induced in rats with streptozotocin. They were fed either with wheat bran as a source of insoluble dietary fibre or guar gum as soluble dietary fibre. The effect of these fibres on intestinal and renal disaccharidases in diabetic rats was studied. Activities of intestinal maltase, sucrase and lactase increased during diabetes, which was ameliorated to a considerable extent in fibre fed groups. The activities of disaccharidases in renal tissue was decreased in diabetic rats and there was an improvement in fibre fed group.

L-アラビノースは小腸スクラーゼを特異的に阻害し, ショ糖の消化吸収を抑制する。実験動物ではショ糖負荷後の血糖上昇を用量依存的に抑制することが認められている。本研究では, ヒトにおけるショ糖含有食品摂取後の血糖上昇およびインスリン分泌に及ぼすL-アラビノース添加の効果を, 健常者 (48例) および2型糖尿病患者 (10例) で検討した。試験はクロスオーバー法または群間比較試験で行った。その結果, (1) 健常者 (8例) を対象にショ糖50gを摂取させた試験で, L-アラビノース添加ショ糖摂取群では血糖値および血中インスリン値の上昇が有意に抑制された。(2) 健常中高年 (40例) を対象にショ糖含有食品 (ゼリー: ショ糖含有量30g) を摂取させた試験で, L-アラビノース添加群では血糖値の上昇が添加濃度に依存して抑制された。(3) 2型糖尿病患者を対象とした試験でも, L-アラビノース添加ショ糖の有用性が認められた。(4) すべての試験において消化器症状等の副作用は認められなかった。以上より, L-アラビノースは健常者および2型糖尿病患者において安全にショ糖摂取後の血糖上昇を抑制することが明らかになった。

The intracellular sucrase SacA from Zymomonas mobilis was purified to homogeneity from a recombinant E. coli strain containing the SacA gene under an expression system. The protein was monomeric with a molecular mass of 58 kDa. The sucrase activity was maximal at 25 °C and thermal stability of the purified protein was low (50% recovery after 30 min at 46 °C ). The activation energy was low at 33 kJ mol−1. Maximum activity was at pH 6.5. Activity was strongly inhibited (>99%) by SH blocking reagents and reducing agents slightly (10–60%) increased the activity of purified SacA. The sucrase showed a low KM (42 mM) and kcat (125 s−1) which indicated its very low efficiency for sucrose hydrolysis. A mutant strain of Z. mobilis not able to grow on sucrose was isolated. This strain (ZM4S) lacked the two sucrases SacB and SacC but SacA was present in the intracellular fraction. Therefore, SacA alone is unable to allow growth Z. mobilis on sucrose.

The use of hyper-prolific sows results in large litters but also leads to an increasing number of supernumerary and underprivileged (e.g. low birth weight (LBW)) piglets. The effects of artificial rearing on the growth, small intestinal morphology and digestion capacity of these piglets remain unclear. Therefore, the aim of this study was to assess the effect of sow-feeding versus formula-feeding on piglets' structural and functional gut maturation. To this purpose, pairs of LBW and normal birth weight (NBW) piglets (n=40) were allocated to four treatment groups. Groups 1 and 2 contained piglets that suckled until either d 10 or 28 of age, respectively. Groups 3 and 4 contained animals that suckled until 3 d of age and were then formula-fed until either d 10 or 28. During d 3-10, formula-fed piglets showed reduced average daily gain (ADG; -112 g d(-1)) and lactase activities (-4.50 U g(-1) tissue) compared to suckling piglets (P < 0.01). In contrast, animals that were formula-fed until d 28 had a comparable ADG compared to sow-fed pigs. In addition, formula-fed piglets had a greater absorptive area (P < 0.01; +59.1 mu m(2)), maltase and sucrase activities (P < 0.05; +0.97 and +0.23 U g(-1) tissue) and deeper crypts (P < 0.03; +42.5 mu m) compared to suckling piglets. In general, the differences between LBW and NBW piglets were scarce. These results suggest that the combination of ad libitum access to formulated milk and an increased capacity to absorb nutrients makes artificial rearing a good alternative to raise supernumerary and/or LBW piglets. (C) 2013 Elsevier B.V. All rights reserved.

The effect of feeding high-moisture maize grains dried in the sun or artificially in a forced draught oven at 80, 90 or 100 °C for 24 hours and supplemented with microbial enzymes (Avizyme 1502 and Phyzyme XP) on growth performance, visceral organs, tissue protein, enzyme activity and gut development was investigated in a broiler growth trial. Feed intake (FI) up to 21 days decreased as a results of oven drying of grains whereas supplementation with microbial enzymes increased FI compared to the non-enzyme diets (881.1 vs. 817.2 g/bird). The highest FI (900 g/bird) was found only in sun-dried grain diets. There was no effect of grain drying temperature or enzyme supplementation on FI when assessed at 7 days of age. Up to day 21 there was a reduction in live weight (LW) with increase in grain drying temperature while supplementation with enzymes significantly improved LW only on the diets containing sun-dried grains (731 g/bird) and grains dried at 90 °C (634 g/bird). Live weight was significantly higher in chickens on the enzyme supplemented diets than on diets without enzymes (638 vs. 547 g/bird). The feed conversion ratio (FCR) at this age was poorer with an increase in grain drying temperature but improved when the diets were supplemented with enzymes (1.48 vs. 1.62 g/g). There was an increase in the relative weight of the small intestine and liver with an increase in grain drying temperature at day 21 but there was no difference in the relative weight of these organs when the diets were supplemented with enzymes. Only the activities of the alkaline phosphatase at day 7 and maltase and sucrase at days 7 and 21 increased as a result of grain drying treatment but not by microbial enzyme supplementation. The ileal digestibility of gross energy, protein and starch was not significantly changed with an increase in grain drying temperature or by enzyme supplementation. The concentrations of ileal formic and acetic acids and caecal propionic and valeric acids were significantly increased by an increase in grain drying temperature but not affected by the microbial enzyme supplementation. The populations of lactic acid and lactobacilli bacteria in the ileal content were reduced on diets containing enzymes but were not affected by an increase in grain drying temperature. In the caecal content, the total anaerobic bacterial count was higher in birds on diets supplemented with microbial enzymes (8.1 vs. 7.8 log10 cfu x/g digesta). The resident lactic acid bacteria population also increased as a result of an increase in grain drying temperature. From results of the current study, diets based on sun-dried maize or maize dried at 90 °C provided comparatively better gross response. It may be inferred that there was a positive response to addition of microbial enzymes. Overall, it may be assumed that, for broiler chickens, there is little or no difference in the nutritive value of sun-dried grain and grains artificially dried at 90 °C.

1. Effects of early feeding with a diet containing added putrescine on duck intestinal development and growth performance were examined by a 2 x 2 factorial arrangement with two different feeding times (6 and 48 h) and two levels of putrescine (0 and 025%). 2. A significant main effect of early feeding on increasing body weight (BW) was observed from hatch to 35 d, whereas dietary putrescine had no significant effect on BW. 3. In the first week posthatch, enhanced small intestinal weight and intestinal density (weight of intestinal tissue/unit length of intestine), increased villus length and reduced crypt depth were observed in the early feeding group, while no effect was observed when putrescine was added to the diet. 4. Maltase and sucrase activity and protein/DNA ratio in jejunum were increased by early feeding in the first week, while decreased by putrescine supplementation. 5. In conclusion, early feeding methods have great potential for small intestine development and thereafter enhanced the growth performance of ducks, but dietary putrescine used during this period should be used cautiously to avoid toxicity.

Glycoside hydrolase family 13 (GH-13) mainly contains starch-degrading or starch-modifying enzymes. Sucrose hydrolases utilize sucrose instead of amylose as the primary glucosyl donor. Here, the catalytic properties and X-ray structure of sucrose hydrolase from Xanthomonas campestris pv. campestris are reported. Sucrose hydrolysis catalyzed by the enzyme follows Michaelis-Menten kinetics, with a K(m) of 60.7 mM and a k(cat) of 21.7 s(-1). The structure of the enzyme was solved at a resolution of 1.9 A in the resting state with an empty active site. This represents the first apo structure from subfamily 4 of GH-13. Comparisons with structures of the highly similar sucrose hydrolase from X. axonopodis pv. glycines most notably showed that residues Arg516 and Asp138, which form a salt bridge in the X. axonopodis sucrose complex and define part of the subsite -1 glucosyl-binding determinants, are not engaged in salt-bridge formation in the resting X. campestris enzyme. In the absence of the salt bridge an opening is created which gives access to subsite -1 from the ;nonreducing' end. Binding of the glucosyl moiety in subsite -1 is therefore likely to induce changes in the conformation of the active-site cleft of the X. campestris enzyme. These changes lead to salt-bridge formation that shortens the groove. Additionally, this finding has implications for understanding the molecular mechanism of the closely related subfamily 4 glucosyl transferase amylosucrase, as it indicates that sucrose could enter the active site from the ;nonreducing' end during the glucan-elongation cycle.

The interactions of gallic acid and tannic acid with purified brush border sucrase (EC 3.2.1.48) from mouse intestine have been studied. These findings indicate that both gallic acid and tannic acid inhibit sucrase activity, which is pH dependent. Kinetic analysis revealed that enzyme inhibition by gallic acid is a pure V effect at pH 5.0, which changes to mixed type at pH 7.2, and pure K effect at pH 8.5. In contrast, sucrase inhibition by tannic acid was a pure K effect at acidic pH and uncompetitive type in the alkaline pH range. Far-CD spectroscopic analysis revealed an increase in the helicity of the enzyme at acidic pH in the presence of tannic acid but no change at alkaline pH. Fluorescence spectra revealed a red shift in λmax of the enzyme, suggesting that tryptophan residues come to a more hydrophilic environment in the presence of polyphenols. These findings suggest that inhibition of mice sucrase by polyphenols is pH dependent, and is associated with conformational modifications of the enzyme.

Congenital sucrase-isomaltase deficiency (CSID) is characterized by absence or deficiency of the mucosal sucrase-isomaltase enzyme. Specific diagnosis requires upper gastrointestinal biopsy with evidence of low to absent sucrase enzyme activity and normal histology. The hydrogen breath test (BT) is useful, but is not specific for confirmation of CSID. We investigated a more specific 13C-sucrose labeled BT.Determine whether CSID can be detected with the 13C-sucrose BT without duodenal biopsy sucrase assay, and if the 13C-sucrose BT can document restoration of sucrose digestion by CSID patients after oral supplementation with sacrosidase (Sucraid).Ten CSID patients were diagnosed by low biopsy sucrase activity. Ten controls were children who underwent endoscopy and biopsy because of dyspepsia or chronic diarrhea with normal mucosal enzymes activity and histology. Uniformly labeled 13C-glucose and 13C-sucrose loads were orally administered. 13CO2 breath enrichments were assayed using an infrared spectrophotometer. In CSID patients, the 13C-sucrose load was repeated adding Sucraid. Sucrose digestion and oxidation were calculated as a mean percent coefficient of glucose oxidation averaged between 30 and 90 minutes.Classification of patients by 13C-sucrose BT percent coefficient of glucose oxidation agreed with biopsy sucrase activity. The breath test also documented the return to normal of sucrose digestion and oxidation after supplementation of CSID patients with Sucraid.13C-sucrose BT is an accurate and specific noninvasive confirmatory test for CSID and for enzyme replacement management.

The effects of a cafeteria diet on the small intestine were investigated in adult Wistar rats under sedentary conditions and after physical training.Parameters including morphometry, enzyme activities, and total myenteric populations in the jejunum were evaluated.The cafeteria diet, characterized as hyperlipidic, produced obese rats, corroborated by increases in the Lee index and the weights of the periepididymal and retroperitoneal adipose tissues (P0.01). Obesity caused increases in the length of the small intestine, villi height, crypt depth, whole-wall thickness (P0.05), and the enzymatic activities of alkaline phosphatase, lipase, and sucrase (P0.01), in addition to a reduction in the number of goblet cells (P0.05). With reference to the jejunal intrinsic innervations, the total number and area of myenteric neurons was unchanged regardless of the group. Physical training promoted 1) a reduction of the weight in the retroperitoneal and periepididymal adipose tissues (P0.05) and 2) an increase in the thickness of the muscular layer (P0.05).The cafeteria diet promoted obesity in rodents, leading to alterations in morphometry and enzymatic intestinal parameters, which were partily attenuated by physical training.

Summary A study was conducted to investigate the effect of the key cereal grains and a microbial enzyme supplement on broiler chicken performance, gut microflora and intestinal function. Ingestion of the barley-based diet was associated with low 28-day body weight, decreased feed intake and high FCR. The supplemental enzyme increased feed intake and weight gain of the chickens on a wheat-based diet. The pH of the gizzard and caecal contents varied with the grain type. Enzyme supplementation reduced ileal viscosity, particularly in birds that received the diet based on wheat. The birds on the barley-based diet had lower ileal digestibility of dry matter, protein and energy than those given maize and sorghumbased diets. The ileal digestibility of starch was increased by enzyme supplementation. Enzyme supplementation increased the number of total anaerobic bacteria in the gizzard of birds fed on sorghum and increased lactobacilli in the gizzard of those fed both sorghum and wheat. The birds fed the sorghum-based diet had the lowest counts of caecal total anaerobic bacteria and lactobacilli. Jejunal villus height and villus:crypt ratio of birds fed the barley-based diet were the lowest when compared with those fed the other diets. Enzyme application induced an increase in villus height and villus:crypt ratio of birds on wheat, crypt depth on barley and a reduction in crypt depth of chickens on the sorghum-based diets. The highest activity of maltase and the lowest activity of sucrase were observed in tissue from birds fed on maize and sorghum-based diets respectively. The differences in the performance of broilers on cereal grains could be explained by changes in intestinal morphology, enzyme activities and gut microflora as well as nutrient digestibility. The improved performance by supplemental enzyme in wheat-fed chickens was associated with beneficial changes in intestinal morphology and digesta viscosity.

The effects of supplementing a barley-based diet for weaned piglets withexogenous beta-glucanase and xylanase on gastrointestinal digestiveenzyme activities were investigated. Thirty-six cross-bred weaned pigletswere randomly assigned to two groups with three pens based on sexand mass. Each group was fed on the diet based on barley with or withoutadded beta-glucanase and xylanase (0.15%) for a 4-week period. Theresults showed that enzyme supplementation improved growth performanceof piglets significantly (p < 0.05), but had no effect (p = 0.091)on average daily feed intake. The results also showed that supplementationof beta-glucanase and xylanase had no effect on pepsin activity in gastriccontents but slightly decreased (p = 0.092) the pepsin activity ingastric mucosa. Meanwhile, no effect of enzyme supplementation ontrypsin activity in duodenal contents was observed. However, the activitiesof amylase and lipase in duodenal contents were significantly(p < 0.05) decreased, whereas the activities of maltase, sucrase andgamma-glutamyl transpeptidase (gamma-GT) in jejunal and ileal mucosa wereenhanced significantly (p < 0.05). The improvement of disaccharidaseand gamma-GT activity may be attributed to the positive impacts of exogenousenzymes on digestion and absorption of the nutrients. In conclusion,the current results indicated that supplementation with enzymes in barley-based diets could improve the growth performance of piglets,decrease the activities of amylase and lipase in duodenal contents andincrease the activities of disaccharidase and gamma-GT in jejunal and ilealmucosa.

1. 1. Small but significant differences were observed in the total and specific activity of larval midgut sucrase among nine strains of the silkworm, Bombyx mori. The hybrid strain that is commercially available for use of cocoon production showed a rather high activity, which might indicate the significant role of this enzyme in the silkworm physiology. 2. 2. Three species of soluble midgut sucrase were isolated on column chromatography of DEAE-cellulose from the fifth instar larvae in nine silkworm strains. They were named Peaks III, II and I according to the order of elution from the column. Peak II was a predominant soluble sucrase. 3. 3. The kinetic parameters of three soluble sucrases in the midgut tissue from a hybrid silkworm strain were investigated. pH optima were pH 5.5–7.5, pH 6.4 and pH 6.3–7.4 in Peaks I, II and III, respectively (hereafter we refer to the data in this order). K m values toward sucrose at pH 6.5 were 7.5 mM, 14.8 mM and 5.1 mM. Substrate inhibition was observed in three soluble sucrases above 200 mM. Metal ions such as Cu2+, Pb2+, Zn2+ and Fe3+ activated three soluble sucrases markedly, as much as 17-fold against the control in Peak III with Cu2+. Tris and Tricine showed inhibition against three soluble sucrases. Tris inhibited three soluble sucrases similarly, in a mixed type of inhibition. K i values of Tris were 3.5 mM. 3.2 mM and 0.5 mM. 4. 4. These results indicate that three soluble sucrase in the larval midgut of the silkworm, Bombyx mori are the distinct entities with similar kinetic properties but with distinct kinetic parameters and suggest that they play a role slightly different from each other in the midgut cell.

The natural diet of aphids, plant phloem sap, generally contains high concentrations of sucrose. When pea aphids (Acyrthosiphon pisum) were fed on chemically defined diets containing sucrose radiolabelled in the glucose or fructose moiety, 2 to 12-fold and 87 to 110-fold more radioactivity was recovered from the tissues and honeydew, respectively, of aphids that ingested [U-(14)C-glucose]-sucrose than from those ingesting [U-(14)C-fructose]-sucrose. The total radioactivity recovered was 70% of the ingested [U-(14)C-glucose]-sucrose and5% of ingested [U-(14)C-fructose]-sucrose. The dominant honeydew sugars produced by aphids feeding on 0.75 M sucrose diets were oligosaccharides comprising glucose. In vitro the guts of pea aphids had high sucrase activity, 1-5 U mg(-1) protein, generating equimolar glucose and fructose except at high sucrose concentrations where glucose production was inhibited (K(si)=0.1 M). These data suggest that the fructose moiety of ingested sucrose is assimilated very efficiently and may be preferentially respired by the aphid, and that the glucose moiety of sucrose is incorporated into oligosaccharides by the transglucosidase activity of the gut sucrase at high sucrose concentrations. These differences in the fate of sucrose-derived glucose and fructose are important elements in both the carbon nutrition and osmoregulation of aphids.

The ontogenetic development of intestinal digestive functions for avian species other than the domesticated chicken are not well documented. Therefore, this study was conducted to resolve the developmental patterns of some intestinal digestive functions in White Pekin ducks. The ducks were killed and their intestines harvested when they were 1, 3, 5 and 7 wk old. Several small intestinal tissue characteristics, sucrase and alkaline phosphatase (ALP) activities of homogenates from the small intestine mucosa were measured, and the small intestinal L-threonine uptake capacities were estimated with brush border membrane vesicles prepared from the corresponding age groups. Between 1 wk (0.37 +/- 0.04 kg) and 7 wk (3.79 +/- 0.06), posthatch ducks exhibited relative body growth rates of 352, 77 and 28% from 1 to 3, 3 to 5 and 5 to 7 wk, respectively. Allometric changes in small intestine weight indicated that the small intestine grew in direct proportion to the duck's metabolic body weight. Total homogenate sucrase activity per unit body weight did not differ (P0.05) among the age groups studied. Total homogenate ALP activity per body weight was lower at 3 wk than at 1 wk (P0.05) but did not differ (P0.05) among 3, 5 and 7 wk-old ducks. The development pattern of L-threonine uptake capacities normalized to body weights paralleled the course of relative body growth rates.

Factors, such as insulin, found in human and pig colostrum and mature milk likely influence small intestinal growth and development. Although pharmacologic doses of insulin injected parenterally may accelerate small intestinal development in altricial animals such as the rodent, the effects of oral insulin on intestinal development have not been studied. In the first of two studies, we randomized 2-d-old miniature piglets to receive bottle-feedings of a swine weaning milk formula with (group F + I) or without (group F) the addition of insulin. Serum glucose, insulin, and cortisol were measured before and 1 h after the first feeding the piglets received at our facility. In the second study, piglets were randomized (groups F and F + I) and fed for 6 d, after which blood samples were obtained as in the first experiment. The piglets were then killed and the small intestine removed for analysis. We found no differences between groups in serum glucose, insulin, and cortisol at both 2 and 8 d of age, both before and after feeding. In the second experiment, small intestinal weight was greater in the F + I than in the F group. Although no differences were noted between groups in the jejunum, values were greater for group F + I versus group F for ileal mucosal weight, protein, RNA, lactase, and maltase activities. No differences were found between groups in ileal DNA or sucrase activity. We conclude that the administration of oral insulin stimulated an increase in ileal mass and disaccharidase activity in the newborn miniature pig without apparent concomitant changes in serum glucose, insulin, or cortisol.

Lactase and sucrase are two disaccharidases that differ not only in their substrate specificity and developmental patterns, but also in their resistance to mucosal insult. In this experiment, we tested the hypothesis that there might be a dichotomy in expression of enzyme activity along the jejunal villuscrypt unit. Sectioning of the villus-crypt unit in a cryostat enabled direct comparison of the distribution of lactase and sucrase enzyme activities in the adult rat. There is a stepwise increase in mean lactase/sucrase ratio going from crypt to villus. The data indicate that unlike sucrase activity, which is expressed maximally in enterocytes along the entire villus, maximal lactase activity is not attained until midvillus. The delay in expression of maximal lactase activity might help to explain the vulnerability of this enzyme to acute mucosal insult such as occurs in viral gastroenteritis.

1. The effects of low-protein and protein-free diets on the levels of disaccharidase, peptidase and aldolase activities in the jejunal mucosa of rats were studied.2. Maltase, palatinase and sucrase activities increased significantly after both types of feeding, although there was an initial fall with the protein-free diet.3. The rise in lactase levels was, however, not so marked.4. Glycyl-glycine and glycyl-leucine dipeptidase levels fell consistently with both diets.5. Aldolase activities were generally unaltered, but tended to fall if the period of low-protein feeding was prolonged.6. Enzyme levels rapidly returned to normal when the rats were given a normal diet after a period on a protein-deficient one.7. It is suggested that the rise in disaccharidase and fall in peptidase levels are adaptive changes to the high-carbohydrate, low-protein diet, with diminished enzyme synthesis, due to lack of nitrogen, contributing to the lowered peptidase activities. The relevance of these results to disaccharide intolerance in chronic malnutrition, kwashiorkor and gastro-intestinal infection is discussed.

Intestinal sucrase activity of the rat varies with the age, but not the sex, of the animal. Sucrase activity of rats 23 days of age was approximately two-thirds that of adults.Sucrase activity of adult rats was significantly decreased by several days of fasting. The decrease was rapid during the first 2 to 4 days of the fast, but became negligible thereafter.Diets containing large (70%) amounts of sucrose, galactose, melizitose, or α-methyl-D-glucoside produced highly significant increases in intestinal sucrase levels (compared with a carbohydrate-free, high-casein control diet) when fed ad libitum for 24 hours to adult male rats previously fasted for 3 days. Similar diets containing fructose, fructose plus glucose in equimolar amounts, or maltose significantly increased sucrase activity, but diets containing glucose, mannose, xylose, or lactose were not stimulatory. A 70% raffinose diet significantly decreased sucrase activity. Normal male rats which were fed the 70% sucrose diet for 4 weeks had sucrase activities similar to those of controls fed Purina fox checkers, but animals fed the carbohydrate-free, high-casein diet for 1 day or longer had sucrase activities significantly lower than those of controls. The significance of these observations in regard to enzyme "adaptation" is discussed.

Reductions in weight gain, feed consumption and feed efficiency resulted under the stress of water restriction or high population density. The metabolizable energy (ME) content of the feed was unaffected by the severity of the stresses. Elevated and depressed environmental temperatures resulted in reductions in weight gain and feed efficiency, but there were no alterations in the ME content of the feeds. Water restriction decreased the sucrase activity, but not the maltase activity in the intestinal mucosa. Overcrowding had no effect on the level of these mucosal enzymes. At adverse temperatures mucosal sucrase and maltase activities were significantly higher for birds on a low energy than for those on a high energy diet. On the low energy, but not the high energy regime, the sucrase and maltase activities were increased at the elevated and depressed environmental temperatures.

This study determined the time required for the adaptive changes in human jejunal sucrase and maltase activities when dietary carbohydrate was changed from glucose to sucrose, sucrose to carbohydrate-free, and glucose to fructose. Four volunteer subjects were studied. The time for the increases and decreases in activity was 2 to 5 days and there was no further change for 9 weeks thereafter. This time response is similar to the estimated time for intestinal epithelial cell turnover in the small intestine of man. It is proposed that the changes in disaccharidase activity produced by changes in dietary sugar content are due primarily to an effect on the crypt cell. The effect becomes increasingly manifest as these crypt cells divide and migrate up the villus.