Localization of acyl-coenzyme A: cholesterol acyltransferase in villus and crypt cells of chick intestine

Endogenous cholesterol esterification by acyl-CoA:cholesterol acyltransferase (EC 2.3.1.26) was studied in isolated enterocytes obtained from chick duodenal, jejunal, and ileal villi and crypts, using [14C]oleoyl-CoA as substrate. The maximal specific activity in each cell fraction was found in chick jejunum, followed by duodenum and ileum. Jejunal upper and mid villi showed higher specific activities than lower villi and crypts. Epithelial cells isolated from chick intestine also incorporated oleoyl-CoA into different lipids using the endogenous substrates. Upper and mid villus cells showed the maximal incorporation of oleoyl-CoA into triglycerides in duodenum and jejunum. Levels of oleoyl-CoA incorporation into phospholipids were higher than those found in the synthesis of triglycerides or cholesterol esters, whatever may be the cell fraction considered. Upper villus cells also showed the highest specific activity in the incorporation of oleoyl-CoA into phospholipids. The acyl-CoA hydrolase specific activity was practically similar in all the cell fractions obtained from chick duodenum, jejunum, and ileum.     

Effects of force-feeding on immunology,digestive function and oxidative stress in the duodenal and jejunal mucosa of Pekin ducks

Force-feeding was considered as a traditional high-efficiency approach to improve growth performance and accelerate fat deposition of Pekin ducks. However, force-feeding is a serious violation of international advocacy on animal welfare, because it can induce serious injuries to animals, such as damages to the digestive tract, effects on immunity and even severe oxidative stress. Therefore, it is urgent to stop force-feeding. The aim of this study was to determine the effects of force feeding on immune function, digestive function and oxidative stress in the mucosa of duodenum and jejunum of Pekin ducks. A total of 500 ducks were randomly divided into two groups. The control group was allowed to feed freely on a basal diet. The experimental group was force-fed by inserting a plastic feeding tube 8 to 10 inches long down the esophagus for 6 days. Compared with the control group, there was a significant (P<0.05) increase in serum diamine oxidase, d-lactic acid, endotoxin and corticosterone levels in the force-feeding group. The crypt depth in duodenum and jejunum showed significant differences (P<0.05) between the two groups and the intestinal villus epithelium cell was severely damaged in force-feeding group. Similarly, the activities of digestive enzymes as well as the levels of immune function in the duodenal and jejunal mucosa in the force-feeding group were significantly higher than the control group (P<0.05). However, there was a significant decrease in the superoxide dismutase, glutathione peroxidase and catalase levels with a marked increase in malondialdehyde level in duodenal and jejunal mucosa (P<0.05). In summary, at the end of the fattening period with force-feeding for 6 days, Pekin ducks experienced an adverse effect on the integrity of their duodenal and jejunal mucosa epithelium cell as well as their immune function and antioxidant capacity of Pekin ducks but also had improvement in digestive enzyme activities.     

Effects of Aflatoxin B1 Exposure and Sodium Selenite Supplementation on the Histology,Cell Proliferation,and Cell Cycle of Jejunum in Broilers

The aim of this study was to investigate the effects of aflatoxin B₁ (AFB₁) exposure and sodium selenite supplementation on the histology, cell proliferation and cell cycle of jejunum in broilers. A total of 240 1-day-old male AA broilers were divided into four groups of 60 each, fed with basal diet (control group), 0.3 mg/kg AFB₁ (AFB₁ group), 0.4 mg/kg supplement Se (Se group), and 0.3 mg/kg AFB₁?+?0.4 mg/kg supplement Se (AFB₁ + Se group) for 21 days, respectively. Compared with the control group, decreased jejunal villus height, villus height/crypt ratio, and proliferation cell nuclear antigen (PCNA)-positive cells, and G₂/M phase arrest and shedded epithelial cells on the tip of jejunal villus were observed in AFB₁ groups at 7 and 14 days of age. However, the villus/crypt ratio, PCNA-positive cells and cell percentage of G₀/G₁, S, and G₂/M phases had no significant differences between AFB₁ group and control group at 21 days. Simultaneous supplementation with sodium selenite restored these parameters to be close to those in control group. In conclusion, 0.3 mg/kg AFB₁ in the diet inhibits the development of broiler’s jejunum by reducing cellular proliferation and inducing G₂/M arrest during only the first 2 weeks after hatching. Supplementation of dietary sodium selenite at the concentration of 0.4 mg/kg Se had protective action against these toxic effects of AFB₁.     

Effects of Copper-Loaded Chitosan Nanoparticles on Intestinal Microflora and Morphology in Weaned Piglets

The objective of the present study was to investigate the effects of dietary supplementation with copper-loaded chitosan nanoparticles (CNP-Cu) on growth performance, intestinal microflora, and morphology in weaned piglets. A number of 90 weaned piglets (Duroc × Landrace × Yorkshire), weaned at 21?days with body weight of 7.2?±?0.81?kg, were randomly divided into three groups by weight and sex, each treatment including three replicates of ten pigs. The piglets were fed the same basal diet supplemented with 0 (the control group), 100?mg/kg CNP-Cu, and 100?mg/kg chlortetracycline (the positive group). The results showed that 100?mg/kg CNP-Cu significantly increased average daily gain and feed intake and decreased feed/gain ratio and diarrhea rate (P?<?0.05). Compared with the control group, the amount of Escherichia coli in duodenum, jejunal, and caecum were significantly decreased by 100?mg/kg CNP-Cu; the number of lactobacillus in jejunal and caecum were increased (P?<?0.05), and the amount of bifidobacterium in duodenum and caecum were also increased (P?<?0.05). Moreover, the villous height of duodenum, jejunum, and ileum mucosa was significantly increased (P?<?0.05), and the crypt depth was significantly decreased (P?<?0.05). The results indicated that CNP-Cu is beneficial to growth and intestinal microflora and morphology and could be a potential substitution of chlortetracycline in diets of weaned piglets.     

Effects of Bacillus subtilis and antibiotic growth promoters on the growth performance,intestinal function and gut microbiota of pullets from 0 to 6 weeks

The development of digestive organs and the establishment of gut microbiota in pullets play an important role throughout life. This study was conducted to investigate the effects of Bacillus subtilis (BS) on growth performance, intestinal function and gut microbiota in pullets from 0 to 6 weeks of age. Hy-line Brown laying hens (1-day-old, n = 504) were randomly allotted into four diets with a 2 × 2 factorial design: (1) basal diet group (control); (2) antibiotics group (AGP), the basal diet supplemented with 20 mg/kg Bacitracin Zinc and 4 mg/kg Colistin Sulphate; (3) BS group, the basal diet supplemented with 500 mg/kg BS and (4) mixed group, the basal diet supplemented with both AGP and BS. As a result, when BS was considered the main effect, BS addition (1) reduced the feed conversion ratio at 4 to 6 weeks (P < 0.05); (2) decreased duodenal and jejunal crypt depth at 3 weeks; (3) increased the villus height : crypt depth (V : C) ratio in the duodenum at 3 weeks and jejunal villus height at 6 weeks and (4) increased sucrase mRNA expression in the duodenum at 3 weeks as well as the jejunum at 6 weeks, and jejunal maltase and aminopeptidase expression at 3 weeks. When AGP was considered the main effect, AGP supplementation (1) increased the V : C ratio in the ileum at 3 weeks of age; (2) increased sucrase mRNA expression in the duodenum at 3 weeks as well as the ileum at 6 weeks, and increased maltase expression in the ileum. The BS × AGP interaction was observed to affect average daily feed intake at 4 to 6 weeks, and duodenal sucrase and jejunal maltase expression at 3 weeks. Furthermore, dietary BS or AGP addition improved caecal microbial diversity at 3 weeks, and a BS × AGP interaction was observed (P < 0.05) for the Shannon and Simpson indexes. At the genus level, the relative abundance of Lactobacillus was found to be higher in the mixed group at 3 weeks and in the BS group at 6 weeks. Moreover, Anaerostipes, Dehalobacterium and Oscillospira were also found to be dominant genera in pullets with dietary BS addition. In conclusion, BS could improve intestinal morphology and change digestive enzyme relative expression and caecum microbiota, thereby increasing the efficiency of nutrient utilization. Our findings suggested that BS might have more beneficial effects than AGP in the study, which would provide theoretical evidence and new insight into BS application in layer pullets.     

Distribution of 3-hydroxy-3-methylglutaryl-CoA reductase in isolated villus and crypt cells of chick duodenum, jejunum and ileum

3-Hydroxy-3-methylglutaryl-CoA reductase (EC 1.1.1.34), the major rate-limiting enzyme of cholesterogenesis, was studied in epithelial cells isolated in a villus to crypt gradient from chick duodenum, jejunum and ileum, in order to resolve the apparent controversy that exists on the anatomical localization of sterol synthesis in the intestine. Consistent separation was demonstrated by using the marker enzymes alkaline phosphatase, specific to the villus cells, and thymidine kinase, specific to the crypt cells. No relative difference in stability was observed, as shown by the equal distribution of acid phosphatase. Cells were 90-95 per cent viable. The highest specific activity of reductase was located in the microsomal fraction (41 per cent of the total). The mitochondria had lower specific activity (8 per cent of the total). The distribution of reductase activity in epithelial cells of the villus-crypt axis was also studied. The specific activity in each cell fraction from chick duodenum was clearly lower than that in jejunum and ileum. The jejunal and ileal crypt regions showed lower specific activity than the villus cells. About 70 per cent of total reductase activity was found in cells from the upper and the mid villus fraction in each intestinal segment.     

Betaine aids in the osmoregulation of duodenal epithelium of broiler chicks, and affects the movement of water across the small intestinal epithelium in vitro.

In Experiment 1, the water holding capacity of broiler chick intestinal tissue was studied in vitro. The chicks were fed with corn-based diets with or without a 0.2% betaine supplementation in the drinking water. Slices from duodenum and jejunum were incubated in iso-osmotic (300 mM) or hyperosmotic saline (600 mM) with or without 10 mM betaine. The water volume of tissue slices was studied by adding tritiated water in the incubation medium while [14C]inulin was used to correct for the adherent water. After 30 min of incubation, by which time the steady-state of tritium influx had been achieved, the 3H and 14C-activities of the tissue slices were measured. The ileal and duodenal tissues incubated in the hyperosmotic saline accumulated less tritium than those incubated in iso-osmotic saline. Duodenal slices incubated in hyperosmotic saline with the presence of betaine showed a tritium content similar to slices incubated in iso-osmotic saline. The data suggest that the presence of betaine helped the duodenal, but not jejunal, epithelium to maintain water balance in hyperosmotic conditions. The dietary betaine supplementation diminished the differences between the incubation treatments in duodenal, but not in ileal tissue. In Experiment 2, the same double labeling method, but with shorter incubation times, was used to assess the rate of water flux from the incubation medium to duodenal or jejunal slices. The dietary treatments (as in Experiment 1) had little effect on the results. Betaine in the hyperosmotic saline significantly decreased the rate of tritium accumulation into the tissue slices, indicating that betaine slowed down the influx of water to the epithelium. We suggest that betaine affects the movement of water across the intestinal epithelium and has a role in the osmoregulation of small intestine of broiler chicks.     

Effects of melatonin on acetylsalicylic acid induced gastroduodenal and jejunal mucosal injury

We evaluated the effects of melatonin on acetylsalicylic acid (ASA) induced gastroduodenal and jejunal mucosal injury. We used 40 postpubertal rats divided randomly into five groups of eight animals. The control group consisted of untreated animals. The Mel group was injected intraperitoneally (i.p.) with 5 mg/kg melatonin. The ASA group was injected i.p. with 200 mg/kg ASA. The ASA + Mel group was injected i.p. with 5 mg/kg melatonin 45 min after administering 200 mg/kg ASA i.p. The Mel + ASA group was injected i.p. with 5 mg/kg melatonin 45 min before administering 200 mg/kg ASA i.p. We found no statistically significant differences in mean histopathological scores in the ASA + Mel group compared to the ASA group. ASA caused shortened villi and loss of the apical villus in the duodenum. The histopathological score was increased and villus height was decreased in the ASA group compared to untreated controls. Treatment with melatonin attenuated the histological damage. In the ASA group, occasional areas showed erosion of villi in the jejunum; however, differences in mean histopathological score in ASA group compared to the other groups were not statistically significant. Malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD) activities were measured in stomach, duodenal and jejunum tissue. We found increased MDA activity in both stomach and duodenal tissues in the ASA group compared to the control group (p < 0.05). We found no statistically significant changes in MDA levels in jejunal tissue in the ASA group compared to the control group. We found no change in SOD activity in either stomach or duodenal tissues in the ASA group compared to the control group. We observed decreased SOD activity in jejunal tissue in the ASA group compared to the control group (p < 0.05). We detected no change in GSH activity in stomach, duodenal or jejunal tissues in the ASA group compared to the control group. The stomach damage was less in melatonin treated groups, but the lesions were not completely eliminated. The jejunum in the ASA group retained a nearly normal appearance. We found that melatonin exhibited some healing effects on ASA induced duodenal mucosal injury.     

5-Hydroxytryptophan modulates postprandial motor patterns of canine proximal small intestine

The aim of the study was to clarify whether 5-hydroxytryptophan (5-HTP) stimulates the postprandial motor pattern of the duodenum in a similar way as that of the adjacent jejunal segment in dogs. Computerized analysis of motor patterns recorded by closely spaced strain gauges focused on the temporal and spatial distribution of the contractions. Results indicate that 5-HTP increased the incidence and the length of the spread of contraction waves after both an acaloric and a nutrient meal in the duodenum as well as in the adjacent jejunal segment. Effects were more pronounced after the nutrient than after the acaloric meal. After the nutrient meal, but not after the acaloric meal, 5-HTP additionally enhanced the number of both duodenal and jejunal contractions per minute and increased the force of duodenal contractions. The acaloric meal induced significant differences in the motor patterns between the duodenum and the adjacent jejunum. 5-HTP abolished these differences owing to a relatively stronger stimulation of duodenal motility. 5-HTP did not affect gastric emptying of both meals. We conclude (i) that 5-HTP is a potent stimulator of propagated contractions both in the duodenum and the adjacent jejunal segment and (ii) that intestinal motor patterns can be regulated independently of gastric emptying.     

Dietary supplementation with l-arginine or N-carbamylglutamate enhances intestinal growth and heat shock protein-70 expression in weanling pigs fed a corn- and soybean meal-based diet

This study determined effects of dietary supplementation with l-arginine (Arg) or N-carbamylglutamate (NCG) on intestinal health and growth in early-weaned pigs. Eighty-four Landrace × Yorkshire pigs (average body weight of 5.56 ± 0.07 kg; weaned at 21 days of age) were fed for 7 days one of the three isonitrogenous diets: (1) a corn- and soybean meal-based diet (CSM), (2) CSM + 0.08% NCG (0.08%), and (3) CSM + 0.6% Arg. There were four pens of pigs per diet (7 pigs/pen). At the end of a 7-day feeding period, six piglets were randomly selected from each treatment for tissue collections. Compared with the control group, Arg or NCG supplementation increased (P < 0.05): (1) Arg concentrations in plasma, (2) small-intestinal growth, (3) villus height in duodenum, jejunum and ileum, (4) crypt depth in jejunum and ileum, (5) goblet cell counts in intestinal mucosae, and (6) whole-body weight gain in pigs. Real-time polymerase chain reaction and western blotting analyses revealed that both mRNA and protein levels for heat shock protein-70 (HSP70) were higher (P < 0.05) in the intestinal mucosae of Arg- or NCG-supplemented pigs than in the control group. Furthermore, the incidence of diarrhea in the NCG group was 18% lower (P < 0.01) than that in the control group. Collectively, these results indicate that dietary supplementation with 0.6% Arg or 0.08% NCG enhances intestinal HSP70 gene expression, intestinal growth and integrity, and the availability of dietary nutrients for whole-body weight gain in postweaning pigs fed a CSM-based diet. Thus, Arg or NCG is a functional ingredient in the weaning diet to improve nutrition, health, and growth performance of these neonates.     

Ultrastructural localization of acid phosphatase activity in the small intestinal absorptive cells of adult rats.

Ultrastructural localization of acid phosphatase activity was investigated in ultrathin (0.05 micron) and semithin (0.5 and 0.75 micron) sections of the small intestinal epithelial cells of adult rats. The results showed that the enzyme activity was localized on the membrane of microvilli, lateral cell membranes, lysosomes, the Golgi complex, and the GERL of Novikoff (a part of the smooth-surfaced endoplasmic reticulum located in close proximity to the inner Golgi saccules) of duodenal absorptive cells. The lysosomes contained within the duodenal and jejunal absorptive cells appeared to be mainly heterolysosomes rather than autolysosomes. The enzyme activity of absorptive cells was lower in the jejunum than in the duodenum, and was barely detectable except in the GERL and lysosomes of the ileum. The average numbers of lysosomes having a diameter of 0.2 approximately 1.0 microns, per cell profile in sections of 214 duodenal, 226 jejunal and 318 ileal epithelial cells were 8.9 +/- 0.189, 6.4 +/- 0.155 and 3.5 +/- 0.027 (mean +/- SE), respectively. From these results, it was assumed that both the Golgi apparatus and GERL produce some lysosomes in the duodenal and jejunal absorptive cells, but only GERL does so in the ileum. It was considered also that because of an unexpectedly high number of lysosomes containes within the epithelial absorptive cells of the proximal intestine of adult rats, these cells may possess the strong heterophagic, as well as absorptive capacity.     

Contractile activity of duodenum, jejunum, and ileum at psychogenic stress in rabbits before and after muscarinic or nicotinic cholinoceptor blockade

In chronic experiments on rabbits, myoelectric activity (contractile activity index) in distal part of the duodenum, proximal and distal parts of the jejunum and proximal part of the ileum was studied under psychogenic stress caused by rigid fastening rabbit to a table in supine position. In duodenum, the stressor impact rendered stimulating, and in an ileum--inhibitory influence on their motility. In a jejunum the inhibition with the subsequent stimulation was observed, the latter being more expressed in a proximal part of the intestine. The proximo-distal gradient of exitatory and inhibitory influences of the psychogenic stress on contractile activity of the small bowel was revealed: in distal direction, inhibitory influences strengthen and stimulatory ones weaken. The muscarinic receptor blockade abolished increase of the duodenal and jejunal contractile activity obsereved in the control. The nicotinic cholinoceptor blockade abolished increase of the duodenal contractile activity in the 1-st phase of the stressor response and did not exclude an increase of the duodenal contractile activity in the 2-nd phase of the response. Muscarinic or nicotinic blockade did not influence the manifestation of the inhibitory reaction of proximal part of the ileum. In the period after release of the animal, the duodenal and jejunal contractile activity exeeded its initial level. This exeeding did not preserve after muscarinic cholinoceptor blockade but did preserve after nicotinic one in duodenum and proximal jejunum. The received data allow to conclude, that produced by the stress increase of the contractile activity of the distal part of duodenum, proximal and distal parts of jejunum produced by the stress, as well as exceeding the initial contractile activity level in the period after release of an animal, are mediated by cholinergic effector neurones of the enteric nervous system.     

热应激对小鼠器官指数、小肠损伤及胃HSP70 mRNA表达的影响

目的探讨热应激对小鼠器官指数、小肠形态、胃黏膜HSP70 mRNA表达量及糖代谢相关激素的影响。方法采用单因子实验设计,将年龄和体重相近的18只KM小鼠随机分为对照组和热应激组,分别测定心、肝、脾、肺、肾重量,小鼠胃黏膜HSP70 mRNA表达量、血浆中胰岛素和胰高血糖素浓度以及十二指肠和空肠的绒毛高度、隐窝深度,并对肝脏、十二指肠和空肠进行病理组织学检查。结果与结论热应激对小鼠器官指数无影响,可显著提高小鼠胃黏膜HSP70 mRNA表达量,降低血浆中胰岛素的含量,并造成小鼠肝脏、十二指肠和空肠严重损伤。     

Histological alterations of intestinal villi in chickens fed dried Bacillus subtilis var. natto

Two experiments were conducted. In experiment 1, chickens were fed dried Bacillus subtilis var. natto for 3 or 28 days. Growth performance and internal organs were not different from controls, but feed efficiency tended to be improved in the 28-day feeding. In these birds, blood ammonia concentration was decreased (P<0.05). Blood glucose concentration, and amylase and lipase activity in the intestinal content were not significantly different among dietary groups. These results suggest that the B. subtilis natto depressed ammonia concentration. In experiment 2, chickens were fed dietary B. subtilis natto for 28 days. These birds had a tendency to display greater growth performance and intestinal histologies, such as villus height, cell area and cell mitosis, than the controls. Flat cell outline on the duodenal villus surface in controls developed large, protruded cell clusters and cell protuberances after feeding of dietary B. subtilis natto. These results indicate that intestinal function was activated by the depressed blood ammonia concentration in the body of the chicken. The present results may suggest that the B. subtilis natto has the potential to be a beneficial microorganism in chickens.     

Dietary alanyl-glutamine improves growth performance of weaned piglets through maintaining intestinal morphology and digestion–absorption function

Alanyl-glutamine (Ala-Gln), a highly soluble and stable glutamine dipeptide, is known to improve gut integrity and function. The aim of this study was to evaluate whether dietary Ala-Gln supplementation could improve growth performance, intestinal development and digestive-absorption function in weaned piglets. A total of 100 purebred Yorkshire piglets weaned at 21 days of age were assigned randomly to four dietary treatment groups and fed a basal diet (control group) or a basal diet containing 0.15%, 0.30% and 0.45% Ala-Gln, respectively. Compared with the control group, piglets fed the Ala-Gln diets had higher average daily gain and lower feed : gain and diarrhea rate (P < 0.05). Moreover, dietary Ala-Gln supplementation increased villous height and villous height : crypt depth ratio in duodenum and jejunum (P < 0.05), as well as the activities of maltase and lysozyme in jejunum mucosa (P < 0.05). In addition, a decrease in serum diamine oxidase activity and crypt depth in duodenum and jejunum was observed in piglets fed the Ala-Gln diets (P < 0.05). Serum cytosolic phospholipase A2 (cPLA2) concentration and gene expression of cPLA2, Na⁺-dependent glucose transporter 1, glucose transporter 2 and peptide transporter 1 in jejunum were increased by feeding Ala-Gln diets relative to control diet (P < 0.05). These results indicated that feeding Ala-Gln diet has beneficial effects on the growth performance of weaned piglets, which associated with maintaining intestinal morphology and digestive-absorption function.     

Effects of dietary chitosan on growth rate,small intestinal morphology,nutrients apparent utilization and digestive enzyme activities of growing Huoyan geese

Dietary chitosan (CS) supplementation could improve the growth rate, small intestinal morphology, nutrients apparent digestibility and digestive enzyme activities in pigs, broiler chickens, rats and fish, whereas no data has been reported about the effect of CS on the growing Huoyan geese. Therefore, this study was designed to investigate the effects of CS on growth rate, small intestinal morphology, nutrients apparent utilization and digestive enzyme activities of growing Huoyan geese. Three hundred and twenty (28 days of age, gender balance) Huoyan geese were randomly divided into control, CS₁₀₀, CS₂₀₀ and CS₄₀₀ groups (based on BW) with 20 geese per pen and 4 replicates pen per group, and the feeding experiment lasted for 4 weeks. The 4 diets contained 0, 100, 200 and 400 mg CS per kg feed, respectively. The results showed that CS₂₀₀ groups had higher average daily gain, final BW, apparent utilization of DM and CP, and lower feed/gain ratio compared with the control group (P < 0.05). Meanwhile, CS₁₀₀ and CS₂₀₀ groups had higher villus height, villus height/crypt depth ratio and lower crypt depth in duodenum and jejunum than those in the control group (P < 0.05). The geese in CS₁₀₀ and CS₂₀₀ groups had higher villus height, villus height/crypt depth ratio and lower crypt depth of ileum compared with those in control and CS₄₀₀ groups (P < 0.05). In addition, compared with the control group, CS₂₀₀ group has higher trypsin activities and lower lipase activities in duodenal, jejunal and ileal contents (P < 0.05). The results suggested that addition of 200 mg/kg CS had positive effects on growth rate, small intestinal morphology, nutrients apparent utilization and digestive enzyme activities of growing Huoyan geese.     

Cell cycle time and rate of entry of cells into mitosis in the small intestine of young rats

Cell cycle time (T(C)) and the rate of entry of cells into mitosis (r(M)) in the jejunum and duodenum of young rats were investigated using the stathmokinetic method. The cell cycle times in the jejunum were 24.3 and 28.3 h in light and dark periods, respectively. Cell cycle times in the duodenum were 17.1 and 21.5 h in light and dark periods, respectively. Rates of entry of cells into mitosis in the jejunum were 1.2 and 1.1 cells/cell/h in light and dark periods and rates of entry of cells into mitosis in the duodenum were 1.4 and 1.8 cells/cell/h in light and dark periods, respectively. Although these changes to cell cycle time values are not statistically significant, the variation between the two periods should be considered in relation to its possible biological effects.     

Effects of a charcoal powder-wood vinegar compound solution in piglets for raw pigeon pea seed meal

Histological intestinal villus alterations were studied in piglets fed a raw pigeon pea meal (PM) diet including a powder mixture of amorphous charcoal carbon and wood vinegar compound solution (CWVC). Twenty-eight male castrated piglets were divided into seven dietary groups of four piglets each. The control group was fed raw PM supplemented to the basal diet (178 g/kg crude protein, 4.23 kcal/g gross energy) at 0 g/kg (CONT), 200 g/kg (PM200) and 400 g/kg (PM400). The treatment groups were fed CWVC in both PM200 and PM400 diet groups at levels of 10 g/kg and 30 g/kg (PM200 + CWVC10, PM200 + CWVC30, PM400 + CWVC10 and PM400 + CWVC30). With increasing dietary PM levels, daily feed intake tended to increase. In contrast, daily body-weight gain tended to decrease, significantly in the PM400 group (P < 0.05), resulting in a significant decrease of feed efficiency in PM groups (P < 0.05). Body-weight gain and feed efficiency were higher in the CWVC groups compared with the PM groups. The duodenum and ileum were longer (P < 0.05) in the PM400 group than in CONT, but were similar to CONT in CWVC groups. The liver was heavier (P < 0.05), whereas the weights of the heart, kidney and stomach were decreased in the CWVC groups than in other groups. Most values for the intestinal villus height, cell area and cell mitosis number were lower in PM groups than those in CONT (P < 0.05) for each intestinal segment; however, these values were higher in CWVC groups than in PM groups (P < 0.05). The epithelial cells on the duodenal villus surface of the PM200 group showed cell morphology almost similar to CONT. However, the PM400 group had a smooth villus surface due to the presence of flat cells. The epithelial cells of the CWVC groups were protuberated, resulting in a much rougher surface than CONT. The current growth performance and histological intestinal alterations in piglets fed PM and PM + CWVC diets demonstrate that the intestinal features might be atrophied by feeding PM, resulting in decreased growth performance. CWVC might prevent the harmful effects of PM dietary toxins on intestinal function, resulting in a normal growth performance.     

The kinetics of intestinal calcium absorption in the rat: an analytical and model building study

The experimental data obtained from in vivo single pass perfusion of duodenal, jejunal, and ileal intestinal segments of 33- and 50-day-old rats have been used to test a series of models for calcium absorption. Each model was checked for the statistical validity and goodness-of-fit with the experimental data. The model adopted for the duodenum and jejunum had two major components, one saturable and the other nonsaturable, and a minor secretory component. This model was not applicable to ileal calcium absorption. Here the secretory component appeared to be much more important, and the absorption parameters varied in such a manner as to suggest that this intestinal segment was capable of short term autoregulation of dietary calcium absorption.     

Prolactin directly stimulated the solvent drag-induced calcium transport in the duodenum of female rats

Prolactin has been reported to stimulate the calcium absorption of the duodenum where three components of the active calcium transport, namely transcellular active, voltage-dependent and solvent drag-induced calcium transport, were identified. It was known that the transcellular active, but not the voltage-dependent, duodenal calcium transport was directly stimulated by prolactin. The present study thus aimed to evaluate the direct action of prolactin on the solvent drag-induced duodenal calcium transport by using the Ussing chamber technique. The jejunum was used as a reference for the existence of solvent drag and the widening of tight junction induced by cytochalasin E. Results showed that the solvent drag-induced calcium transport existed in both intestinal segments, but the magnitude was significantly greater in the duodenum (29.27+/-2.27 vs. 17.31+/-1.65 nmol h(-1) cm(-2), P<0.001). We further demonstrated that 200, 600 and 800, but not 1000 ng/ml, prolactin significantly promoted the solvent drag-induced duodenal calcium transport in a dose-response manner, i.e. from the control value of (nmol h(-1) cm(-2)) 24.31+/-2.36 to 45.42+/-3.47 (P<0.01), 63.82+/-5.28 (P<0.001) and 53.93+/-5.41 (P<0.01), respectively. However, prolactin did not manifest any effect on the jejunum. Because the paracellular transport was suggested to be size-selective as well as charge-selective, further experiments were designed to evaluate the mechanism by which prolactin stimulated the solvent drag-induced calcium transport. The duodenum was exposed to 20 microM cytochalasin E, 600 ng/ml prolactin or the combination of both in the presence of a paracellular marker 3H-mannitol, while the jejunum was a positive reference. The results showed that, in the jejunum, cytochalasin E alone and cytochalasin E plus prolactin significantly increased the mannitol fluxes from (micromol h(-1) cm(-2)) 0.29+/-0.04 to 0.49+/-0.03 (P<0.05) and 0.48+/-0.05 (P<0.05), respectively, while having no effect on the calcium fluxes. Prolactin alone had no effect on the jejunal calcium flux. In the duodenum, neither mannitol nor calcium fluxes were enhanced by cytochalasin E, however, prolactin still increased the solvent drag-induced calcium flux from 27.74+/-2.41 to 51.03+/-4.35 nmol h(-1) cm(-2) (P<0.001). It was concluded that prolactin directly stimulated the solvent drag-induced duodenal calcium transport in a dose-response and biphasic manner without the widening of tight junction.