Specific Activities Of Maltase 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.

Gut Digestive Function and Microbiome after Correction of Experimental Dysbiosis in Rats by Indigenous Bifidobacteria.

In recent years, great interest has arisen in the use of autoprobiotics (indigenous bacteria isolated from the organism and introduced into the same organism after growing). This study aimed to evaluate the effects of indigenous bifidobacteria on intestinal microbiota and digestive enzymes in a rat model of antibiotic-associated dysbiosis. Our results showed that indigenous bifidobacteria (the Bf group) accelerate the disappearance of dyspeptic symptoms in rats and prevent an increase in chyme mass in the upper intestine compared to the group without autoprobiotics (the C1 group), but significantly increase the mass of chyme in the colon compared to the C1 group and the control group (healthy animals). In the Bf group in the gut microbiota, the content of opportunistic bacteria (Proteus spp., enteropathogenic Escherichia coli) decreased, and the content of some beneficial bacteria (Bifidobacterium spp., Dorea spp., Blautia spp., the genus Ruminococcus, Prevotella, Oscillospira) changed compared to the control group. Unlike the C1 group, in the Bf group there was no decrease in the specific activities of maltase and alkaline phosphatase in the mucosa of the upper intestine, but the specific activity of maltase was decreased in the colon chyme compared to the control and C1 groups. In the Bf group, the specific activity of aminopeptidase N was reduced in the duodenum mucosa and the colon chyme compared to the control group. We concluded that indigenous bifidobacteria can protect the microbiota and intestinal digestive enzymes in the intestine from disorders caused by dysbiosis; however, there may be impaired motor function of the colon.

Elephant foot yam ameliorates activities of intestinal and renal disaccharidases in streptozotocin induced diabetic rats

Elephant foot yam (Amorphophallus paeoniifolius (Dennst.) Nicolson syn. Amorphophallus campanulatus) is a tuber vegetable used as an ingredient in ayurvedic preparations for various ailments. The present investigation deals with the effect of elephant foot yam extract on intestinal and renal disaccharidases in normal rats and streptozotocin induced diabetic rats. The specific activities of maltase, sucrase and lactase were measured in control and starch fed diabetic (SFD), elephant foot yam extract at 0.1% fed diabetic (YFD0.1), elephant foot yam extract at 0.25% fed diabetic (YFD0.25) and aminoguanidine fed diabetic (AFD) groups at the end of experimental period. Intestinal maltase, sucrase and lactase activities were high in SFD group compared to control, YFD0.1, YFD0.25 and AFD groups. Amelioration of intestinal maltase activities by 18% 26% and 48% was observed in YFD0.1, YFD0.25 and AFD groups respectively when compared to SFD group. Intestinal sucrase activity was ameliorated in YFD0.1, YFD0.25 and AFD groups to about 28%, 45% and 56% respectively. Lactase activity of intestine was improved by 36%, 52% and 64% in YFD0.1, YFD0.25 and AFD groups respectively. On the contrary, specific activities of renal maltase, sucrase and lactase were decreased in SFD group compared to control groups. Supplementation of elephant foot yam extract in diet significantly ameliorated renal disachharidases activities in YFD0.1 and YFD0.25 groups. The results demonstrate the potential use of elephant foot yam for the management of diabetes.

Effects of flavonoids on α-glucosidase activity: Potential targets for glucose homeostasis

ObjectiveFlavonoids are naturally occurring compounds widely distributed in plants, which have hypoglycemic potential and have been described as glucosidase inhibitors. This study evaluated the effect of flavonoids on intestinal glucosidase activity after in vivo and in vitro treatment. MethodsFor the in vivo studies animals received quercetin by gavage and for the in vitro assays a segment of the small intestine was used. To obtain the oral glucose tolerance curve fasted normal rats were loaded with glucose plus flavonoids. The glycemia was measured by the glucose oxidase method. ResultsQuercetin reduced the effect of sucrase and maltase in the in vivo and in vitro treatments. It was observed in the in vitro studies that the maximum inhibitory effect of kaempferitrin was around 23% for maltase activity. Also, for the sucrose substrate the specific enzyme activity was significantly decreased. Aglycone, flavonoids, and kaempferol decreased significantly the maltase activity at all concentrations assayed. Finally, rutin reduced maltase-specific activity at all concentrations studied. According to the oral glucose tolerance curve, rutin reduced the serum glucose levels at 15, 30, and 60 min when administered by oral gavage 30 min before glucose overload in rats. ConclusionBased on these results, we can conclude that disaccharidases are targets of flavonoids in the regulation of glucose absorption and consequently glucose homeostasis.

Exploring the Potential of C. Pasteurianum to Produce Biofuels from Waste Products

Biofuels which can be produced by microorganisms from agricultural waste products will provide a renewable and non controversial source of energy for the future. The saccharolytic Clostridium sp. can ferment a wide range of sugars to produce organic acids and solvents. They are also anaerobic and in some cases thermophilic which is advantageous for large-scale industrial processes. C.pasteurianum shows potentially high solvent and hydrogen gas production capacity. The fermentation end products of C.pasteurianum, when grown in media of high sugar content, included significant quantities of acetone, butanol and ethanol, acetate, butyrate, CO2 and H2. The aim of this research was to investigate maltose uptake and metabolism in Clostridium pasteurianum NCIB 9486, to increase understanding of its starch utilisation. The organism was grown in different substrates and assayed for induction of glucosidase activities. Results confirmed that enzyme synthesis is induced by substrates.MaltaseandpNPGasewere found largely in soluble form (89.5% and 86.6% respectively) proving that maltase is produced intracellularly and hydrolysis of maltose takes place in the cytpoplasm. Fractionationof the soluble extract ofmaltose growncells yielded two maltase enzymes, maltase I (120-150 KDa) and maltase II (60 KDa). Further characterisation of maltase II showed high substrate specificity for maltose and its analogues, and sucrose. Maltase II exhibited similar rates of hydrolysis of maltose andmaltotriose: values for Km of 0.8 and 0.7 mmol l-1;Vmax of 3.3 and 4.2 nmol min-1, respectively. There is indication of specific activity of maltase II in cleaving the -1,4 (maltose) and -1,6-(isomaltose) linkages, but not -linkages (cellobiose). PEP-dependent phosphorylation of maltose was demonstrated suggesting the presence of a PEP-dependent PTS for maltose transport. This species has potential for use in biofuel production and a better understanding of its carbohydrate metabolism will facilitate its exploitation.

Effects of dietary mannanoligosaccharide on growth performance, nutrient digestibility and gut development of broilers given different cereal‐based diets

A feeding trial was conducted to evaluate the effects of mannanoligosaccharide (MOS) on the growth performance, nutrient digestibility and gut development of broilers given a corn or a wheat-based diet over a 21-day experimental period. Dietary MOS improved the growth performance of birds given the wheat-based diet compared to that of birds given the corn-based diet during 7-21 days of age. In line with this, the ileal digestibility of starch was increased by MOS at 21 days of age. The addition of MOS modulated the development of gut microflora. From day 7 to day 21, the numbers of mucosa-associated coliforms along the small intestine were decreased; whereas the numbers of mucosa-associated lactobacilli were increased by MOS, regardless of the cereal type in the diets. Dietary MOS also reduced the counts of coliforms and Clostridium perfringens in the caeca of birds by 21 days of age. Villus height at the jejunum was not affected by MOS but the crypt depth and the muscularis thickness were reduced. The specific activities of maltase and alkaline phosphatase were increased in birds given the MOS-supplemented diet; whereas the development of leucine aminopeptidase was delayed by MOS. All these changes in the mucosal morphology and function were dependent on the type of cereal and/or the age of the birds.

Cloning and overexpression of a maltase gene from Schizosaccharomyces pombe in Escherichia coli and characterization of the recombinant maltase

The Schizosaccharomyces pombe maltase structural gene ( SPMAL1 +) was amplified from genomic DNA of S. pombe by PCR. An open reading frame of 1740 bp, encoding a putative 579 amino-acid protein with a calculated molecular mass of 67.7 kDa was characterized in the genomic DNA insert of plasmid pQE30. The specific maltase activity in the induced transformants was 21 times higher than that in wild-type. However, the estimated molecular mass of the purified recombinant maltase was 44.3 kDa by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The optimal temperature and pH of the purified recombinant maltase were 40 °C and 6, respectively. The recombinant maltase was weakly activated by Mg 2+, Ca 2+, Na +, and Ba 2+, but was strongly inhibited by Hg 2+, Ag + and Cu 2+, EDTA, and PMSF. The purified maltase could actively hydrolyse ρ-nitrophenyl glucoside (PNPG), maltose, dextrin, and soluble starch. The results demonstrate that maltase from S. pombe was different from that from other yeasts, and might be usefully exploited in the future by the biotechnology industry or lead to the development of new molecular genetic tools.

Influence of starch and casein administered postruminally on small intestinal sodium-glucose cotransport activity and expression

Twenty-four Holstein steer calves (88 ± 3kg) with abomasal catheters were randomly assigned within blocks to one of four treatments. The treatments consisted of four abomasal infusions: water (control), 4 g/kg BW.d-1 of partially hydrolyzed starch (SH), 0.6 g/kg BW.d-1 of casein, and a mix of SH + casein. The small intestine was collected and five equidistan, 1m sites were identified (duodenum, jejunum 1, jejunum 2 jejunum 3 and ileum). Maltase specific activity in mucosal homogenate and brush border membrane vesicles, SGLT1 protein abundance, and sodium-dependent glucose uptake in brush border membrane vesicles did not differ between the calves receiving different abomasal infusion treatments. However, maltase specific activity in homogenates and brush border membrane vesicles increased four-fold from the duodenum to the first jejunal site before declining steadily towards the ileum (p=0.0145 p=0.0020, respectively). The SGLT1 abundance differed by intestinal sampling site (p=0.0162). These data indicated that cattle might not have the ability to alter the capacity for glucose uptake when challenged with different substrates and that the regulation of SGLT1 expression could differ between bovine and other species.

Oral administration of spermine advances intestinal maturation in sucking piglets

AbstractThe objective of this study was to investigate the effect of orally administered spermine at various doses on intestinal maturation in sucking piglets. Thirty-six 11-day-old sucking piglets were assigned randomly to one of six treatments to receive via a stomach tube 0, 0·1, 0·2, 0·3, 0·4, or 0·5 mmol spermine per kg live weight (LW) per day for 3 days. At day 14 of age, duodenum, jejunum and ileum were obtained for biochemical and morphological analysis. Increasing the dose of orally administered spermine increased intestinal weight (linear effect, P&lt;0·01), mucosal weight (linear effect, P&lt;0·05), and mucosal protein, DNA and RNA contents of the duodenum (linear effect, P≤0·01) and jejunum (linear effect, P&lt;0·01). Elevating spermine doses also enhanced (linear effect, P≤0·02) the specific activities of maltase and sucrase but decreased (linear effect, P&lt;0·01) lactase specific activity in the jejunum and duodenum. Furthermore, augmenting oral doses of spermine increased crypt depth and villus width but reduced villus height in the jejunum (linear effect, P&lt;0·05) and duodenum (linear effect, P&lt;0·01). For most measurements, the effects were observed at the oral spermine doses of 0·3 to 0·5 mmol/kg LW per day. Collectively, the results show that oral administration of optimal doses of spermine to 11-day-old sucking piglets induces precocious intestinal maturation and promotes intestinal growth.

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.

Studies on inositol-mediated expression of MAL gene encoding maltase and phospholipid biosynthesis in Schizosaccharomyces pombe

In this study, the effects of inositol addition on expression of the MAL gene encoding maltase and phosphatidylinositol (PI) biosynthesis in Schizosaccharomyces pombe (a naturally inositol-requiring strain) were examined. We found that specific maltase activity was at its maximum when the concentration of added inositol reached 6 microg ml(-1) in a synthetic medium containing 2.0% (w/v) glucose. When the concentration of added inositol was 1 microg ml(-1) in the medium, repression of MAL gene expression occurred at glucose concentration higher than 0.2% (w/v). However, when S. pombe was cultured in the synthetic medium containing 6 microg ml(-1), repression of maltase gene expression occurred only at initial glucose concentration above 1.0% (w/v). More mRNA encoding maltase was detected in the cells grown in the medium with 6 microg ml(-1) inositol than in those grown in the same medium with 1 microg ml(-1) inositol. These results demonstrate that higher inositol concentrations in the synthetic medium could derepress MAL gene expression in S. pombe. PI content of the yeast cells grown in the synthetic medium with 6 microg ml(-1) of inositol was higher than that of the yeast cells grown in the same medium with 1 microg ml(-1) of inositol. This means that PI may be involved in the derepression of MAL gene expression in S. pombe.

Zinc-deficient diet impairs adaptive changes in the remaining intestine after massive small bowel resection in the rat.

An investigation was conducted on the influence of the presence of zinc in an elemental diet on the mucosa of residual intestine after massive small bowel resection. A total of 34 male Sprague-Dawley rats were divided into five groups: control animals (n = 10) were killed after overnight fasting; a second group (n = 14) underwent massive small bowel resection preserving 10 cm of terminal ileum, and the third group (n = 10) underwent sham operation. Animals in the second and third groups were fed either a commercially available elemental diet or a zinc-deficient diet for 2 weeks; they were then killed. In animals receiving the zinc-deficient diet, a significant decrease (P < 0.05) was noted in plasma zinc and total protein, and in mucosal wet weight (duodenum), thickness (duodenum and ileum), and protein (duodenum) and DNA (duodenum) content. Mucosal sucrase and maltase specific activities in the duodenum and ileum fell but diamine oxidase levels did not. These results suggest that zinc plays an important role in intestinal adaptation in the rat, and indicate that this trace element is essential for intestinal mucosal preservation in this animal.

Intestinal effects of long‐lasting spermine ingestion by suckling rats

Spermine ingestion induces the precocious maturation of the small intestine in suckling rats. Previous observations suggest that spermine-induced intestinal maturation is a two-step phenomenon. The first step is the elimination of immature enterocytes (4-10 h post spermine ingestion) and the second step is the replacement of previous immature cells by adult-type enterocytes (2-3 days post initial spermine administration). The spermine-induced maturation is reversible when spermine administration is stopped. This work was undertaken in order to check whether the extension of polyamine administration (for 3-7 days) after the appearance of spermine-induced maturation can retain the mature state of the small intestine. Our results indicate that extension of spermine administration does not prevent some parameters (sucrase and maltase specific activities) reverting to a typical 'immature' value while others remain at a typical 'mature' level (mucosal weight and lactase specific activity). Our results show that there are at least two different mechanisms in required for the control of spermine-induced maturation of the small intestine.

Influência da adição de probiótico e/ou prebiótico em dietas de leitões desmamados sobre as atividades das enzimas digestivas e parâmetros sangüíneos

This experiment used forty-four piglets weaned at 21 days, fed with five diets (T1 – basal diet; T2 – basal diet + antibiotic; T3 – basal diet + probiotic; T4 – basal diet + prebiotic; T5 – basal diet + synbiotic) and slaughtered at three different ages (at the weaning, 7 and 14 days post-weaning). Immediately after slaughter, samples of the small intestine were collected for enzyme determination. Blood samples of the piglets were collected in the same moments after weaning for hemogram analysis. The results showed that the products added in the diet did not alter the intestinal mucosa enzymes activity; even so, an increase (P&lt;0,05) was observed in the sacarase and maltase specific activity after weaning (7 and 14 days) in the piglets receiving prebiotic. The tested substances did not influence the blood parameters values studied.

Atlantic salmon ( Salmo salar) and rainbow trout ( Oncorhynchus mykiss) digest and metabolize nutrients differently. Effects of water salinity and dietary starch level

Atlantic salmon (average weight: 199 g, group size: 55) and rainbow trout (average weight: 565 g, group size: 25) of the same age, kept in freshwater (FW) or full-strength seawater (SW), were fed diets containing 7% (LCH) or 23% (HCH) precooked maize starch, replacing dietary protein. The fish were fed ad libitum in triplicate groups. Feed intake was monitored. The species appeared quite similar regarding thermal growth coefficient (TGC); 3.09% and 3.14% for the salmon and the trout, respectively, and retention of digestible protein; 45.9% and 43.9%, and energy; 45.7% and 46.9%, respectively. Rainbow trout showed higher digestibilities than Atlantic salmon, most pronounced with the HCH diet. Digestibilities were negatively affected by starch level in Atlantic salmon, less severe in rainbow trout. Hepatosomatic index was higher in rainbow trout than Atlantic salmon when fed the HCH diet. Liver lipid, liver glycogen, plasma glucose and plasma insulin were higher in rainbow trout than in Atlantic salmon at both starch levels. The difference was greatest with the HCH diet. In Atlantic salmon, the HCH diet elevated only liver glycogen. Specific activities of maltase and iso-maltase were substantially higher in the rainbow trout than in the Atlantic salmon. In seawater, Atlantic salmon showed higher TGC than in FW. Rainbow trout seemed unaffected by salinity. Salinity did not affect body composition significantly, except for ash, which was higher in SW than in FW in both species. Digestibility of protein, starch, freeze dry matter and energy was higher in FW than in SW. For starch digestibility, this was true for Atlantic salmon only. Retention of protein, but not energy, was higher in SW than FW. No significant effects of water salinity were observed with regards to condition factor, dress-out percentage, HSI, liver lipid, liver glycogen, plasma glucose or plasma insulin. The high starch diet reduced TGC in both species with no significant effect on FCR or body composition. Negative effects of starch level were observed on digestibility of macronutrients and energy in Atlantic salmon, but not in rainbow trout. Retention of digestible energy was not significantly affected by starch level, indicating that starch energy can replace protein energy. The results clearly showed stimulating effects of dietary starch on mucosal maltase, sucrase and lactase activities in both Atlantic salmon and rainbow trout, contrary to results of previous research. The response in leucine aminopeptidase showed adaptation according to protein level.

Development of the digestive tract in the ostrich (struthio camelus)

A study was conducted to investigate changes in the development of the gastrointestinal tract (GIT) in relation to body growth of growing ostriches. There was an 11-fold increase (P < 0.001) in body weight between 3 and 72 days of age. The relative (to body weight) weight of the proventriculus/gizzard, caeca and colon also increased (P < 0.001) with age. The relative weight of the small intestine peaked at 41 days of age and then tended to decline (P < 0.05) subsequently. The relative weight of the pancreas peaked at 27 days of age and remained fairly stable thereafter. The activities of chymotrypsin and lipase declined (P < 0.001) with age between 3 and 72 days. At 3 days of age, the protein content of the duodenal mucosal homogenate was higher (P < 0.001) than that of the jejunum or ileum, but at all subsequent periods the jejunal protein content was the highest. The protein content of the intestinal brush-border membrane was higher (P < 0.001) at the jejunum than at the duodenum or ileum. The specific activity of maltase declined (P < 0.001) with age in all three regions, most especially between 3 and 27 days of age. The activity of alkaline phosphatase (AP) at 41 and 55 days of age was higher (P < 0.001) in the duodenum than in the jejunum or ileum. The activity of AP fluctuated with age in the duodenum but there was a more defined decline (P < 0.001) with age in the jejunum and ileum. The relative protein content of the liver increased (P < 0.001) with age, with two peaks at 27 and 55 days of age. Arginase activity was not detected in the liver of 3-day old chicks and was not significantly affected by age between 27 and 72 days of age. The pattern of development observed is similar to that in growing poultry. There is, however, a need for evaluation at closer intervals in early life as well as an in-depth assessment of the morphometry of the intestinal mucosa.

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.

Small Intestinal Morphology and Disaccharidase Activities in Early‐weaned Piglets Fed a Diet Containing Spray‐dried Porcine Plasma

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

Body and intestinal growth of broiler chicks on a commercial starter diet. 2. Development and characteristics of intestinal enzymes

1. Investigations were conducted into the development of intestinal enzyme function in broiler chickens on a commercial starter diet. The differences between intestinal regions and localisation of enzymes on the villus were assessed. 2. The specific activity of maltase, sucrase, aminopeptidase N (APN) and alkaline phosphatase (AP) at all intestinal sites decreased with age. There were also variations between intestinal sites although this variation depended on age. The specific activity of maltase was higher than that of the other enzymes examined, regardless of age and intestinal site. The total activities of the enzymes also increased with age at all intestinal sites. 3. Results of the localisation of enzymes on the crypt : villus axis showed that activity was expressed over a large proportion of the villus. There was an increase in the total villus activity of α -glu cosidase (AG), APN and AP with age. Activity per unit villus surface area was similar between ages, except for jejunal AP. At hatch enzyme activity was expressed over 44.1, 55.8 and 63.3% of villus height in the duodenum, jejunum and ileum, respectively. At 21 d of age, corresponding values were 68.7, 65.6 and 77.2%. The point of peak activity from the crypt : villus junction increased with age. In the jejunum, most enterocytes were capable of secreting active enzymes within 1 h of formation. Cells maintained their secretory capabilities until they were more than 60 h old in the case of AG. 4. Although the specific activities of the enzymes were maximal at hatch, the digestive capacity of older birds may be sustained by an increase in total enzyme activity brought about by increased surface area. The pattern of enzyme activity along the gastrointestional tract (GIT) and crypt : villus axis is similar to that reported for some mammalian species.

Development of disaccharidase activity in the small intestine of broiler chickens

1. The changes in disaccharidase activity in the small intestine of broiler chickens were investigated in isolated enterocytes on d 18 of embryonic development and d 1, 7, 21, 35 and 56 after hatching. 2. The specific activities of maltase, lactase and trehalase were greatest on d 18 of embryonic development. After hatching, maltase specific activity gradually decreased until d 18. 3. After d 7 postnatally only traces of lactase and trehalase activity were found in the enterocytes. 4. Significant sucrase activity was found on d 18 of embryonic development and the activity of this enzyme increased 2-fold after hatch and remained generally constant up to d 35, after which the enzyme specific activity declined.