Densitometric analysis of aminopeptidase M activity in small intestine mucosa in piglets experimentally infected with Isospora suis

In gnotobiotical and conventional piglets infected a day post partum (DPP) with oocysts of the coccidium Isospora suis, densitometrical analysis of the activity of aminopeptidase M (EC.3.4.11.2; APM) was performed in the area of microvillous zone of the small intestine. Piglets were infected with different infection doses of oocysts (100,000 oocysts) in gnotobiotical piglets and 200,000 oocysts in conventional piglets). In infected gnotobiotical piglets, the APM activity was studied in the period from the 3rd to 11th day after infection (DAI) and in infected conventional piglets in the period of to the 2nd to 10th day after infection (DAI). Control piglets, in the group of the gnotobiotical animals at the age of 2 to 5 days in the group of the conventional animals at the age of 4 to 7 days, had different APM activity in the microvillous zone of the intestinal mucosa. It was stated that the microvillous zone of the intestinal mucosa gained higher values in control conventional piglets (+7.01 mean values of density). In infected gnotobiotical piglets the density fall of the reaction product of APM was demonstrated already on the third day with further marked reduction of APM density on the 4th day after infection in the whole small intestine with predominance of the persisting APM activity in ileum. Even despite the slight increase in the density of the reaction product of APM in the period from the 5th to 7th DAI (the highest increase in APM density on the 6th DAI), a further decrease of the activity was recorded again on the 8th and namely the 9th DAI in the whole small intestine (the lowest value of density was found in the rear jejunum), the ileum mucosa being affected, too. A slightly higher density of the reaction product of APM was found in the duodenum. On the 10th DAI the APM density started to change and on the 11th DAI in the duodenum and in the middle jejunum it even reached higher values in comparison with the control data. Some differences were proved in the infected conventional piglets in comparison with the development of the APM activity in the small intestine mucosa in the infected gnotobiotical piglets. On the 3rd and 4th DAI APM defect occurred in the whole small intestine, with APM density prevailing in the ileum mucosa (like in the group of infected gnotobiotical piglets). The second period of decrease in APM activity lasted for almost four days (6th to 9th DAI).(ABSTRACT TRUNCATED AT 400 WORDS)     

Histochemistry of selected peptidases in small intestine mucosa in piglets experimentally infected with Isospora suis

In the small intestine mucosa of 24 gnotobiotical piglets experimentally infected the first day post partum with oocysts of the coccidium Isospora suis, the activities of dipeptidylpeptidase IV (EC.3.4.14.5.; DAP IV) and gamma-glutamyl transferase (EC.2.3.2.2.; GGT) in the microvillous zone of enterocytes were evaluated by scanning densitometry. The tissue of the small intestine in piglets infected with a dose of 100,000 oocysts of the coccidia of I. suis was examined in the period from the first till the eleventh day post infection (DPI). In the control piglets at the age of 2-5 days it was found that most of the DAP IV activity was located in the microvillous zone of the enterocytes of the middle jejunum, rear jejunum and ileum. The DAP IV activity of duodenum mucosa was lower; as compared with the activity in the mucosa of the jejunum and ileum it reached 53-57%. In the case of GGT activity, the highest density values of the reaction product were recorded in the microvillous zone of enterocytes of the duodenum and the whole jejunum, the lowest in the ileum mucosa (86-89%) of the activity found in the duodenum and jejunum). During the experimental infection the infected piglets had a significant deficit of both peptidases, especially DAP IV (the whole studied period). The development of GGT activity was slightly different with the onset of the marked decline of the enzyme activity only on the fifth DPI. The lower GGT activity persisted till the eighth DPI. The density of the GGT reaction product began to return to the normal on the ninth to eleventh DPI. No predisposition in the location of the deficit was observed in the peptidases studied during the infection. The decline of the activity of both enzymes influenced also the mucosa of all studied parts of the small intenstine. The difference lay in the relevance of lowering of the density of reaction product of DAP IV and GGT on other DPI and in the different intensities of the return of the activity to the physiological normal.     

Alkaline phosphatase activity in goblet cells in the small intestine of piglets experimentally infected with the coccidium Isospora suis

Alkaline phosphatase activity (EC. 3.1.3.1.) in goblet cells was investigated in the small intestine of 16 gnotobiotic piglets infected one day after delivery (DAD) by different rates of oocysts of Isospora suis coccidia. At a high infection rate of I. suis (750,000) the goblet cells were found to be highly positive to alkaline phosphatase on day 3 to day 4 after infection (DAI). In piglets infected by a low infection rate of I. suis oocysts (100,000) the activity of alkaline phosphatase activity in goblet cells was proved on days 4 to 10 after infection. In the first group of piglets, the positive goblet cells prevailed in the middle region of jejunum, with the peak on 4th DAI. It the second group of piglets a marked increase in the alkaline phosphatase activity was recorded in the goblet cells in the posterior part of jejunum on days 4 to 5 after infection and on 10th DAI. No alkaline phosphatase activity in the goblet cells was demonstrated in the control gnotobiotic piglets at the age of two to seven days.     

Density of selected enzymes in the goblet cells of the small intestine in piglets experimentally infected with the coccidium Isospora suis

The density of selected enzymes in the goblet cells of the mucous membrane of the small intestine was studied in a group of 12 gnotobiotic piglets experimentally infected with the coccidium Isospora suis one day after parturition (DPP), using the Vickers M-786 scanning and integrating microdensity meter. At an infecting dose of 100,000 oocysts of I. suis, the histochemistry of the goblet cells of the mucous membrane of the piglets changed significantly in the period of 4 to 10 days after infection (DPI). Increases occur in the density of non-specific esterase (EC. 3.1.1.1.) and acid phosphatase (EC. 3.13.2.). The density of acid and neutral muco-substances declines and the densities of alkaline phosphatase (EC. 3.1.3.1.) and aminopeptidase M (EC. 3.4.11.2) are significantly high. The goblet cells of the mid and posterior parts of jejunum are very similar in their histochemistry in the experimentally infected gnotobiotic piglets. In the duodenum and ileum the histochemical picture of the goblet cells shows no substantial difference from the data recorded in the goblet cells of the mucous membrane of the small intestine of the four control piglets at an age of two to seven days.     

Morphometric analysis of the activity of alkaline phosphatase in the small intestine of piglets infected with the coccidium Isospora suis

Gnotobiotical one-day-old piglets were infected with 100,000 Isospora suis coccidia oocysts, and were immediately killed. In piglets killed on the 3rd to 11th day after infection (DAI), the morphometric analysis of alkaline phosphatase activity was performed in the area of the microvillus zone of small intestine. In the control 2-7 days old animals, the small intestine was not equally supplied with alkaline phosphatase. In duodenum the activity reached 88.37 per cent of the active length of absorbent surface (% LAac), in the middle jejunum 95.98 per cent LAac, in the dorsal jejunum 78.63% LAac and the ileum 90.55 % LAac. The width of the active area was more balanced and ranged from 5.003 microM in the ileum to 6.129 microM in the dorsal jejunum. In infected gnotobiotical piglets the lowest activity was found out on the 3rd to 4th DAI, with a greater decline on the 9th day after infection. The range from 25.99 to 40.50 per cent LAac with minimum in the duodenum and maximum in the ileum was observed on the 3rd DAI. In the middle and dorsal ileum the activity was nearly equal (28.34 and 27.69 per cent LAac). nI the dorsal jejunum a moderate increasing was up to 47.13% LAac on the 4th DAI, with the exception of the ileum, where the activity of alkaline phosphatase decreased to 24.96% LAac. On the 9th DAI the activity of alkaline phosphatase was nearly equal in the whole small intestine (from 55.70 to 60.01% LAac) with the maximum in the middle jejunum. In the width of the reaction product a direct dependence on the total activity of alkaline phosphatase was evident only in the segment of the middle and dorsal jejunum and ileum, but merely on the period of the 3rd to 4th DAI. The lowest values were measured in the middle jejunum (0.982 micron on the 3rd DAI and 0.709 micron on the 4th DAI). No dependence was observed between the total activity and the reaction product in the middle jejunum (0.982 micron on the 3rd DAI and 0.709 micron on the 4th DAI), there was no general stabilisation of the activity of alkaline phosphatase.     

Activity of selected dehydrogenases and monoamine oxidases in the small intestine of gnotobiotic piglets infected with the coccidium Isospora suis

In the small intestine of 16 gnotobiotic piglets infected a day post partum (DPP) by Isospora suis coccidia the activities were studied of selected dehydrogenases and monoaminoxidase (O2 oxidoreductase, MAOx, EC 1.4.3.4.). The following dehydrogenases were investigated: succinate dehydrogenase (SDH, EC 1.3.99.1.), glycerol-3-phosphate dehydrogenase (glycerol-3-phosphate:menadion oxidoreductase, GPOX, EC 1.1.99.5.) and tetrazolium oxidoreductase (NADH, ES 1.6.99.3.). The activities of NADH and GPOX were found to decrease, a decrease being somewhat milder in MAOx, at a high infection dose of I. suis oocysts (750,000 oocysts), in comparison with the control, already on the first day after infection (DAI). The SDH levels did not change. In piglets infected by a low infection dose of I. suis oocysts a double marked decrease (negative to slightly positive finding) was recorded in the period from the third to the eighth day after infection (DAI). A similar pattern with a longer time interval between the decreases was observed in GPOX (4th to 11th day after infection). The findings of SDH and MAOx activities were different. The SDH activity is maintained at the same level (++) for the whole period of investigation and there occurs a decrease (+) only on the 9th day after infection, persisting until 11 DAI. The MAOx activity and its change correspond to the SDH activity; the difference being that in the second group the starting level is high ( ) and on the eleventh day after infection it is low or medium (0-++), in comparison with the standard. This variability is discernible from 8th DAI.     

Lectin histochemistry for glycoconjugates in the small intestines of piglets naturally infected with Isospora suis

Composition of glycoconjugates was examined in small intestines naturally infected with Isospora suis in preweaned pigs by use of 21 biotinylated-labeled lectins with avidin-biotin-peroxidase complex method. As compared with control pig, staining of 18 lectins altered in jejunal villus brush border and goblet cells of pigs naturally infected with I. suis. These results indicate that I. suis infection alters carbohydrate residues on the jejunal intestines.     

The ratio of enterocytes and goblet cells in the mucosa of the small intestine in experimental infection of piglets with the coccidium Isospora suis

The proportions of cup-shaped cells and enterocytes were studied in piglets infected the first and fifth day after birth with 200,000 oocysts of Isospora suis. The greatest imbalance was found in the ratio of the cells of the intestinal mucous membrane in the region of middle and lower jejunum (ratio of 10:1.75)--this was recorded the third to fourth day after infection when the ratio made 10:0.62, whereas in the control animals it was 10:5.7. On the eighth to ninth day after infection the number of cup-shaped cells began to increase, the ratio reaching the values of 10:2.62. Even the 13th day after infection the ratio remained far from normal (10:2.50).     

Mucus synthesis in the goblet cells of the small intestine in experimental infection with the coccidium Isospora suis in piglets

The state of mucus synthesis in the goblet cells of the small intestine was studied in conventional piglets infected with a dose of 200,000 oocytes of the coccidium Isospora suis the first and fifth day after parturition. The synthesis of mucus and its chemical characteristics undergo significant changes during the third and fourth day after infection. The activity of acid and neutral mucous substances declines; their level and the physiological synthetic function of goblet cells begin to return to the normal during the period starting on the eight to tenth day after infection. However, there were no fully functioning goblet cells in the broken numerical ratio even at the end of the period of investigation, i.e. the 13th day after infection. The thin surface layer of mucus remained almost unchanged within the whole extent of the small intestine parts studied.     

Activity of mucosubstances and the goblet cell count in the large intestine of piglets infected with the coccidium, Isospora suis

In a group of conventional and gnotobiotic piglets experimentally infected with the Isospora suis coccidia the quantitative presence of acid and neutral mucous substances in the large intestine and the counts of goblet cells in the surface mucosa and in Lieberkühnis crypts (in the following text called just the crypts) were investigated. In conventional piglets infected with the dose of 200,000 oocysts of I. suis coccidia the lowest content of acid mucous substances was recorded from the eighth to tenth day after infection (DAI). A decrease in the activity of neutral mucous substances was somewhat slower. The lowest count of goblet cells was found on DAI 9, especially on the surface mucosa (4.89 to 4.91 goblet cells per 10 enterocytes). There was observed no difference in the piglets infected the first and fifth day after parturition (DAP). Gnotobiotic piglets infected with the dose of 100,000 oocysts of I. suis coccidia on DAP 1 showed the lowest content of mucous substances in the large intestine from the ninth to tenth day after infection. Unlike the conventional piglets, in gnotobiotic piglets there was recorded a decrease in the content of acid and neutral mucous substances. The gnotobiotic piglets had the lowest counts of goblet cells in the surface mucosa (10:4.57) and in the crypts (10:7.71) on DAI 9. As to the quantitative proportions, in the conventional and gnotobiotic piglets neutral mucous substances prevailed on the other days (DAI 3-7 and DAI 11), similarly like on DAI 8. The results of this investigation revealed a functional disease of the large intestine in conventional and gnotobiotic piglets infected experimentally with the Isospora suis coccidia.     

Alkaline phosphatase activity levels during infection with the coccidia Isospora suis in piglets

The activity of alkaline phosphatase (EC 3.1.3.1.) was studied in the small intestines of piglets infected with the coccidia Isospora suis on the first and fifth day of age. Alkaline phosphatase activity is reduced significantly the third to fourth day after infection (DAI) throughout the small intestine in piglets infected on the fifth day of age. Similar results were obtained in the piglets killed the eighth to tenth DAI which had also been infected on the fifth day of their age. Piglets infected the first day of age and killed on the 8th to 13th DAI exhibited no larger differences from the above-mentioned groups, but alkaline phosphatase activity was distributed more regularly all over the surface of the villi. The normal values, comparable with the controls, were not obtained within 13 days after infection (piglet age 14 days).     

Isospora suis infection in piglets. A review

Recently several reports have been published on the association of Isospora suis with diarrhea in piglets. A review is given of. suis infection in piglets, in which the taxonomy, life cycle, pathogenicity, immunity, and treatment of I. suis and related organisms are discussed.     

Pathogenicity of Isospora suis in gnotobiotic and conventionalised piglets

Isospora suis is unequivocally a primary pathogen of swine. Inoculation of I suis in conventionalised and germ-free piglets caused a biphasic disease course with marked diarrhoea, villous atrophy and necrosis of the intestinal epithelium at four to six and eight to 10 days after inoculation. The presence of a normal bacterial flora markedly (P less than 0.05) influenced the survival rate of piglets but did not appear to affect the histopathological changes observed. Mild limited focal necrosis and bile stasis were present in the liver at eight to 10 days after inoculation. In this period there was also ectasia of lymph vessels in the intestinal lymph nodes.     

beta-D-glucosidase in the microvillous zone of small intestine enterocytes in experimental coccidiosis in suckling piglets]

In the small intestine mucosa of 24 gnotobiotic farrows experimentally infected with the oocysts of coccidiosis of Isospora suis (infection administration--100,000 oocysts) on the first day after the delivery, we carried out the microdensitometric evaluation of the activity of beta-D-glucosidase (phlorizin-hydrolase; hetero-beta-galactosidase; lactase-beta-glucosidase complex; EC. 3.2.1.21). Great attention was paid to the topochemistry of enzyme, deposited in a microvillous zone of enterocytes. We studied likewise the activity of beta-D-glucosidase in the striped fringe of enterocytes of the four control gnotobiotic farrows, in the age from 2 to 5 days. We found out that in healthy farrows the reaction product of studied disaccharidase is located in high concentrations in the microvillous zone of absorptive cells of the whole small intestine. We proved a topographic gradient at which the beta-D-glucosidase activity decreases in control farrows the duodenum mucosa in the aboral direction. When using the choice substrate for beta-D-glucosidase (5-Br-4-Cl-beta-indolyl-3-D-glucoside) we did not prove the enzyme deposition in the small intestine wall. The negative enteral effect of coccidiosis I. suis was provable in the farrows experimentally infected already on the first day after the infection (DPI) when the beta-D-glucosidase activity decreased within the whole small intestine by 15% (ileum) and even by 23% (middle jejunum). The activity reduction had been deepening since the first after the infection and it reached its maximum on the 9th day after the infection when the enzyme concentration in the microvillous zone of absorptive cells reached only 11% of the activity level found in control farrows. On the 10th and 11th day after the infection we registered the increase of the density of beta-D-glucosidase reaction product, however the microvillous zone was even in that final stage of experimental infection significantly deficient (31% of intestine mucosa activity of control farrows).     

Pathogenesis of experimental combined infections with Isospora suis and rotavirus in conventional and gnotobiotic piglets

51 gnotobiotic and 63 conventional, one-, or two-days-old piglets were divided into five groups and infected orally either with Isospora suis or rotavirus alone, or with both agents simultaneously or successively with alternative sequences and various intervals. 15 gnotobiotic and 10 conventional piglets served as controls. The development of small intestinal lesions after infection with I. suis was biphasic. The dominant alteration resulting from rotavirus infection was villus atrophy, considerably more pronounced and extensive in gnotobiotic than in conventional piglets. Synergistic action of I. suis and rotavirus was manifested both clinically, and morphologically. This action culminated at the time of the actual, or presumed development of merogony of I. suis, i.e. on DPI 3 to 5. The action develops only if the intestinal epithelium is damaged functionally and morphologically by a preceding rotavirus infection. It is concluded that the synergistic action is based on a competition of rotavirus and I. suis for mature, enzymatically active absorptive cells.     

猪附红细胞体人工感染小鼠的病理学试验

附红细胞体是寄生于人、猪以及其他动物的红细胞表面、血浆以及骨髓内的一群多形态微生物.猪附红细胞体病缺乏特征性临床症状和病理变化,使发病率和死亡率大大升高,给养殖户造成很大经济损失.本试验旨在研究猪附红细胞体病对小鼠血液生理指标的影响,及对小鼠各脏器的致病程度,为附红细胞体病的诊断及深入研究提供基础试验依据.     

猪等孢球虫研究进展

猪等孢球虫是一种能引起仔猪球虫病的专性寄生性原虫,可引起仔猪严重腹泻甚至死亡,其发病率可高达50%~75%,病死率高达75%,呈世界性流行,严重危害养猪业发展。目前对仔猪球虫病的防控主要以药物预防为主,随着耐药虫株的不断产生及公众对药物残留的高度关注,使得这一防控手段面临巨大挑战,新型抗猪球虫药物、疫苗及其他防控手段亟待研究开发。论文对猪等孢球虫的生活史、基因组学、免疫学及其与其他微生物的互作关系等方面进行综述,以期为仔猪球虫病的综合防控提供参考。     

Detection of rotavirus in experimentally infected piglets.

Scouring and vomiting was induced in piglets by experimental infection with a field strain of rotavirus. Virus or viral antigen was detected in the small intestine by the fluorescent antibody technique and virus could also be demonstrated in infected tissue culture cells by immuno-fluorescence. Progeny particles in the epithelial layer of the small intestine were identified by electron microscopy. Three morphological types could be distinguished, often associated with electron-dense inclusion, and infected cells, though small in number, were present throughout the length of the small intestine.     

仔猪实验性感染新疆猪瘟病毒野毒株的病理学观察

猪瘟 ( Hog cholera,HC)是由猪瘟病毒 ( HCV)引起猪的一种急性、热性、败血性、高度接触性传染病。猪是惟一在自然条件下对 HCV易感的动物 ,该病流行广泛、发病率和病死率高、危害极大 ,因而在国际兽疫局制定的《国际动物卫生法典》中 ,将它列为 A类 1 6种法定传染病之一 ,我国     

Comparison of different methods for examining the feces of suckling piglets for Isospora suis

A highly sensitive diagnostic method is of great importance for detection of I. suis (Isospora suis). In the present study KSFV (combined sedimentation-flotation method) using different flotation solutions (NaCl, ZnSO4, NaCl-sucrose) was investigated regarding sensitivity, costs and expenditure of human labour in comparison to FV (flotation method) using NaCl-sucrose solution and to AM (autofluorescence microscopy). Ninety faecal samples were examined. Using AM, oocysts were detected in 83.3% of the samples. In cases of KSFV and FV, respectively, 41.1% to 53.3% of samples were tested positive. The quantity of detected oocysts was markedly higher in AM than in KSFV or FV. Therefore AM is the most sensitive of the comprised methods. The expenditure of labour is lowest in AM, time exposure is lower in FV than in KSFV. For performance of AM a fluorescence microscope is required contrary to KSFV and FV.