Dehydrogenase activity in small intestine mucosa in experimental coccidiosis in suckling pigs]

The activities of 3-beta-hydroxybutyrate dehydrogenase (EC. 1.1.1.30.; HBD) and isocitrate dehydrogenase (EC. 1.1.1.41; ICD) were evaluated microdensitometrically in the mucosa of duodenum, jejunum and ileum of 19 conventional piglets infected on the first day after parturition (DAP) with oocysts of Eimeria debliecki coccidium (infection dose of 200,000 oocysts). The two investigated enzymes are deposited in mitochondria which are dispersed in the supra-, para- and infranuclear region of absorption cells (Fig. 1). The synthesis of the two dehydrogenases was investigated in the small intestine mucosa in the period of 1st to 10th day after infection (DAI). The HBD and ICD activities were also followed in the small intestine of four control conventional piglets at the age of 2-5 days (Tab. I). The two dehydrogenases could be characterized by a topographic gradient; it means that their activity was increasing in the small intestine mucosa through duodenum in an aboral direction. The ICD activity is higher in the intestinal mucosa of healthy piglets (Figs. 2 and 3), where its topic concentration was more marked while the HBD activity is dispersed in enterocytes (Fig. 4). In infected piglets the density of the two enzymes was demonstrated to decrease already in the starting period of experimental infection, and it reaches the lowest values for the first time on DAI 5-6 (Fig. 5, Tab. II), then on DAIs 9 (HBD; Fig. 6, graph 11)) or 8 (ICD, Fig. 7 and 10). In the period of experimental infection no statistically significant predisposition to the hypoactivity of target dehydrogenases nor its marked shift were observed. Somewhat rapid resumption of synthesis was demonstrated as soon as on DAI 8 in ICD (Fig. 8); its activity on DAI 10 in the intestinal mucosa corresponded to the 93% activity of this dehydrogenase recorded in the small intestine of control piglets. The density of HBD to the same day (DAI 10) reached in the intestinal mucosa of infected piglets the values making only 44.7% of those demonstrated in the intestinal mucosa of the control group of animals.     

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).     

Synthesis of glucose-6-phosphatase in small intestine mucosa during experimental coccidiosis in suckling piglets]

Glucoso-6-phosphatase activity (EC. 3.1.3.9.) was evaluated microdensitometrically in the small intestine mucosa of 19 conventional piglets infected with Eimeria debliecki coccidium oocysts (infection dose of 200,000 oocysts) on day 1 after delivery (DAD). The synthesis of the observed hydrolase was followed within days 1 to 10 after infection (DAI). The activity of the same enzyme was also determined in four control conventional piglets at the age of two to five days. The small intestine mucosa of healthy piglets was found to have relatively balanced glucoso-6-phosphatase concentrations in all observed sections (duodenum, middle and posterior jejunum and ileum). The topographic gradient failed to be demonstrated in control piglets. In piglets experimentally infected with E. debliecki coccidium the glucoso-6-phosphatase activity was decreasing during infection already since DAI 1. The enzyme hypoactivity was still lower in the following days and reached the minimum value at the end of the target period (DAI 10), when its value made only 33% of the concentration recorded in the intestine mucosa of control piglets. The topographic predisposition to the lower activity of glucoso-6-phosphatase was not found to be high. The only exception are DAI 6 and 7, when the lowest enzyme concentration was observed in the duodenum mucosa (52% on DAI 6; 54% on DAI 7). The activity of the observed enzyme was higher in the other sections of small intestine (57% on DAI 6; 62% on DAI 7).     

Histochemistry of acid phosphatase in small intestine mucosa in experimental coccidiosis in suckling piglets]

The activity of acid phosphatase (phosphohydrolase of orthophosphate monoesters; EC. 3.1.3.2) was evaluated densitometrically in the mucosa of duodenum, jejunum and ileum of 22 conventional piglets which were experimentally infected by oocysts of the coccidiae Isospora suis (infection dose of 200,000 oocysts) on day one after parturition (DAP). The activity of the studied hydrolase was investigated in the infected piglets during days two to ten after infection (DAI) in the intestinal mucosa (enterocytes) and in goblet cells. The density of the reaction product of acid phosphatase was simultaneously determined in the same mucosal cells of different sections of the small intestine in five control conventional piglets at the age of 2-14 days. In the small intestine mucosa of control piglets the activity of acid phosphatase was demonstrated to be located especially in the supranuclear zone of enterocytes. As for goblet cells, the reaction product of acid phosphatase is distributed in all zones (supra-, para-, infranuclear zones); the lowest density of this enzyme was found in the infranuclear zone. The activity of acid phosphatase is also localized in intestinal crypts: in their cells the enzyme concentration is decreasing from duodenum to caudal sections. Important changes were revealed, in comparison with the control data, in the development of the activity of acid phosphatase in the intestinal mucosa cells in the experimentally infected piglets. In the period of investigation (DAI 2-10) there were two stages of the development of the density of the enzyme reaction product. The first stage can be characterized by an increase, the other by a decrease in the level of acid phosphatase activity. Enterocytes are influenced in both stages, but the decrease in the density of the reaction product of acid phosphatase was observed only in absorption cells, and not in goblet cells. The increase in the activity of acid phosphatase occurs in the periods of DAI 4 and 9-10. Enzymatic deviations occur mainly in the absorption cells of the mucosa of duodenum and middle jejunum; in the cells of posterior jejunum and ileum an increase in the density of the reaction product of acid phosphatase was also demonstrated, but at the lower quantitative level (especially on DAI 4). The decrease in the activity of acid phosphatase has a protracted development and it takes place on DAI 5 to 8.(ABSTRACT TRUNCATED AT 400 WORDS)     

Histochemistry of nucleoside phosphatases and phosphoglucomutase in the small intestine during coccidiosis in piglets]

The first day after birth, 22 conventional piglets were experimentally infected with the oocysts of the coccidia of I. suis (infection dose 200,000 oocysts). The activity of 5-nucleotidase (5-ribonucleotide phosphohydrolase, EC.3.1.3.5) and phosphoglucomutase (alpha-D-glucoso-1-phosphate phosphotransferase, EC.5.4.2.2) was densitometrically assessed in the mucosa of the small intestines of these piglets. Enzyme activities were studied in the infected piglets during the 2nd to 10th day after infection. The same histochemical examination was simultaneously performed in the intestinal mucosa of five control conventional piglets at an age of 2-14 days. 5-nucleotidase and phosphoglucomutase were found to have a high density in the mucosa of the small intestine of the control piglets: the high-density locations of these enzymes include, first of all, the supranuclear area of the absorption cells, the microvillous zone of enterocytes and the smooth muscle elements of lamina muscularis mucosae. The experimentally infected piglets showed a marked decline of the density of both enzymes during the infection. The deficit affected, for a transient period, the microvillous zone and the supranuclear region of enterocytes; the musculature of the mucous layer was affected permanently. The inactivity was more protracted in the case phosphoglutamase (especially 5 to 9 days after infection). The density of 5-nucleotidase showed a partial return to the normal already the 7th day after infection, with an interruption of resumption of activity on the 10th day. Resumption of enzyme activity in the lamina muscularis mucosae was not recorded during the infection. In the three locations under study, the density of none of the enzymes did reach parameters comparable with the controls at the end of the trial (10 days after infection).     

Use of the anticoccidial agent, tortrazuril (Baycox, Bayer) in coccidiosis in suckling pigs]

At present neonatal coccidiosis caused by Isospora suis is known to be an important disease in piglets. The coccidium I. suis was diagnosed as the causative agent of diarrhoeic disease in piglets on a large pig farm with continuous farrowing operation. The diagnosis of coccidiosis was based on clinical history, gross lesions, histopathology, stained impression smears and aided by detection of oocysts in the faeces. Coccidiosis was associated with diarrhoea in piglets at the age of five to fourteen days. The disease was characterized by variable morbidity and only a portion of the litters was usually affected at one time. The piglets appeared listless, and suffered from yellow watery scours progressing to yellow pasty scours over a three- to five-day period. The lack of response to common antimicrobial therapy, and/or vaccination of sows for E. coli was observed. The prophylactic and therapeutic efficacy of tortrazuril (Baycox, Bayer) against coccidiosis was evaluated in naturally infected piglets. Tortrazuril at a dose of 20 mg/kg, given perorally to each piglet on days 6 and 8 of age, proved to be efficacious in preventing clinical coccidiosis in piglets. Tortrazuril fully controlled the oocyst output, prevented the development of diarrhoea but not improved the weight gains in three-week-old piglets if compared to the untreated controls. The prophylactic and therapeutic efficacy of tortrazuril was compared with another drug--amprolium (Amprovin, MSD). Amprolium at a dose of 100 mg/kg, given perorally to piglets from day 6 to 8 of age, was not efficacious in preventing clinical porcine neonatal coccidiosis. Amprolium reduced the oocyst output, but not prevented the development of diarrhoea. Tortrazuril (Baycox, Bayer) is clearly effective against porcine neonatal coccidiosis caused by I. suis.     

Submicroscopic structure of small intestine cells of lambs during a course of experimental inflammation]

The changes observed in the submicroscopic structure of the enterocytes of the jejunum of lambs in which inflammation has been chemically evoked justify the assumption that 12 hours after application of the chemical agent some differences exist, particularly in cellular reaction in the submucosa, in comparison with inflammations evoked by the infective agent. The submicroscopic changes in the enterocytes correspond to acute inflammation and indicate alterations on cell components which considerably reduce the absorptive area of the intestinal epithelium, and on organellae essential for the function of the enterocyte. In this way the natural barriers in the intestinal wall are damaged, leading to derangements in the absorption and passage of the nutrients taken in.     

Gluconeogenetic capacity of suckling piglets and young pigs]

No marked gluconeogenetic performance was recordable from nursed piglets aged, between one and five days, in response to ACTH nor glucocorticosteroid application. Store pigs, aged twelve weeks, however, exhibited glucose rises of 34 per cent one hour after injection or 55 per cent three hours from ACTH application. The point was made, in an attempt to elucidate the above findings, that in newborn piglets, few days after birth, the gluconeogenetic capacity is insufficient because of functional immaturity of the liver. The behaviours of several metabolites in the liver and muscles of store pigs were examined under differentiated model conditions to check up and verify that view.     

Xanthine oxidase formation during experimental ischemia of the equine small intestine.

We hypothesized that xanthine oxidase plays a role in the postischemic reperfusion injury in the equine small intestine. Under anesthesia, four horses and two ponies underwent ischemic strangulating obstructions of segments of the proximal jejunum, mid-jejunum and ileum. Prior to vascular occlusion, and at 1 h and 2 h of ischemia, full-thickness intestinal biopsies were collected for histopathological evaluation and for determination of combined xanthine dehydrogenase (XDH) plus xanthine oxidase (XO) activity, and XO activity alone. The level of XO activity was expressed in percentage according to the ratio of XO/(XDH + XO). We found a nearly threefold increase in the combined level of XDH plus XO activity from ileum to duodenum (p less than 0.04). However, the preischemic level of % XO activity did not vary significantly (p = 0.61) between segments of jejuno-ileum. Likewise, no significant difference was noted between intestinal segments after ischemia. Therefore, the data from all intestinal segments were pooled for each time and analyzed using Wilcoxon's signed rank test (one-tailed). Compared to the pre-ischemic level of % XO activity (median 27%), the % XO activity increased after 1 h of ischemia (median 37.0%), reaching statistical significance (p = 0.016). There were no statistical differences between the preischemic % XO activity and the % XO activity in non-ischemic bowel at the end of the anesthetic period. During ischemia, % XO activity increased, which lends credence to the importance of xanthine oxidase in previously-documented reperfusion injury in the equine small intestine.     

Lysosomal activity in enterocytes in the small intestine in piglets experimentally infected with Isospora suis

The lysosomal activity of enterocytes of the small intestine mucosa was investigated in gnotobiotic and conventional piglets experimentally infected on the first day after birth (DAB) by the oocysts of the coccidia Isospora suis. A method of the proof of beta-D-glucuronidase (EC.3.2.1.31.) activity was used to demonstrate lysosomes. The piglets were infected by different infection doses of oocysts (100,000 oocysts in gnotobiotic piglets and 200,000 oocysts in conventional piglets). In the gnotobiotic infected piglets the activity of beta-D-glucuronidase in enterocyte lysosomes was investigated in the period from day 3 to day 11 after infection (DAI) and in the infected conventional piglets in the period from day 2 to day 10 after infection. Comparing the control piglets, the group of gnotobiotic piglets at the age of 2-5 days and the group of conventional piglets at the age of 4-7 days, the higher activity of beta-D-glucuronidase was demonstrated in the lysosomes of intestinal mucosa enterocytes in the gnotobiotic control piglets (+5.30 of the average density value, Dx). In the infected gnotobiotic and conventional piglets the pattern of beta-D-glucuronidase activity was found to have three stages in the course of this infection. Two stages can be characterized by a great increase in the enzyme activity (DAI 3-9 in gnotobiotic piglets, DAI 2-3 and 7-9 in conventional piglets. The third stage, which is manifest mainly in the conventional infected piglets, is characterized by a marked decrease in the activity of beta-D-glucuronidase, reaching the level of control findings (DAI 10 and mainly 11 in gnotobiotic piglets. DAI 4-6 and 10 in conventional piglets). A topographical picture shows that the two stages of increase and the stage of beta-D-glucuronidase activity decrease occur in the whole small intestine without any predisposition defect of the enzyme in the different sections of the small intestine.     

Immunohistochemical localization of carbonic anhydrase isoenzymes in salivary gland and intestine in adult and suckling pigs

Localizations of carbonic anhydrase isoenzymes (CA I, CA II and CA III) were investigated immunohistochemically in the salivary glands and intestine of mature and suckling pigs. Carbonic anhydrase isoenzymes were not detected in the salivary glands of sucklings, but were present in the adult. Bicarbonate ion in saliva might be important for the digestion of solid foods in mature pigs, but unnecessary for the digestion of milk in sucklings. Expressions of CA I and CA II were detected strongly in the large intestine of the adult and sucklings, and faintly only at duodenum in the small intestine. CA I and CA II isoenzymes in the large intestine may be involved, at least in part, in ion absorption and water metabolism during digestion and absorption of milk in suckling pigs. In addition, CA I and CA II expression in the duodenal villus enterocyte may support the process of bicarbonate absorption in the duodenum.     

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).     

Morphometry of the small intestine in pigs with ileo-rectal anastomosis.

Ileo-rectal anastomosis (IRA), which is frequently used to measure prececal digestibility in pigs, could induce some disturbances of the normal absorptive function. Our aim was to investigate the effects of different IRA surgical procedures on the main histologic characteristics of the small intestine in pigs. The 4 different IRA procedures compared to intact pigs (INT) were the following: either end to end (EE) or end to side (ES) with or without preservation of the ileocecal valve (EEV, EE, ESV, ES respectively). At 147 d after surgery, samples of the wall of the duodenum, jejunum and ileum were taken under anesthesia and histometric examinations were performed on HE- and PAS-colored sections to estimate changes mainly of mucosa and muscle layers. The values recorded for villus length, crypt depth, and whole thickness of the mucosa suggested that the EE procedures disturb the small intestine less than the ES models. A new parameter, called epithelial quotient and calculated as [(villus length/crypt depth)/mitotic index], was proposed to improve the comparisons. According to this quotient, EE procedures did not significantly affect the mucosa of the whole small intestine. An increased density of goblet cells was recorded in all operated pigs along the small intestine, but mainly in the ileum after EE-IRA. The lymphatic follicle area was reduced. These findings, which were in agreement with a reduced mitotic index in the ileum of EE-pigs, indicated a decreased effect of noxious factors on the small intestinal mucosa in IRA-pigs, especially after the EE-IRA procedure. Some atrophic or hypertrophic effects on the muscle layers were related to the absence or preservation of the ileo-cecal valve. Finally it was concluded that i) there was no major disturbance after IRA, and ii) the end to end procedure was most beneficial for the structural integrity of the small intestine.     

A dynamic model of protein digestion in the small intestine of pigs

A dynamic mathematical model of the digestion of proteins in the small intestine of pigs was developed. The model integrates current knowledge on the transit of digesta along the small intestine, endogenous secretions, digestion of proteins, and absorption of amino acids into a mechanistic representation of digestion. The main characteristics of the model are the following: the small intestine is divided into several segments of variable length but with equal digesta retention time; the rate of transfer of digesta between segments is based on the progression of myoelectric migration complexes; pancreatic and biliary secretions are poured into the first segment, whereas intestinal secretions enter all intestinal segments; protein hydrolysis is described by first-order equations; and an intestinal absorption capacity is used to estimate absorption of hydrolyzed protein. Simulation results are consistent with observed data, although more information is needed to represent reality more closely. The sensitivity analysis shows that parameters for protein hydrolysis largely determine protein digestibility. The absorption capacity of the small intestine limits the absorption of amino acids at the beginning of a meal and modulates the appearance of amino nitrogen in the portal vein. It also shows that amino acid absorption can be limiting to protein digestibility when large amounts of protein are eaten in a single daily meal. The model is useful in evaluating the dynamics of protein digestion and absorption of feedstuffs. The model can be used in evaluating protein digestion of different feedstuffs and feeding strategies.