The Applicability of Agar-Diffusion Test in Measuring Deoxyribonucleases in Pig Intestinal Content

The suitability of an agar-diffusion test (ADT) using toluidine blue deoxyribonucleic acid agar (TDA) for measuring DNase activity in pig intestinal contents was investigated. The ADT was compared with a spectrophotometrical method. Distinct metachromatic zones around wells in the DNA-containing agar, into which the intestinal content was applied, indicated DNase activity. The DNase activity was determined semiquantitatively by making serial twofold dilutions of the intestinal content. The spectrophotometrical method was optimal at pH 7.2. The ADT proved to be most sensitive at pH 5.6. The ability of the 2 methods employed to measure low concentrations of DNases was equal. However, the ADT was considered more suitable than the spectrophotometrical method because ADT measured reduced amounts of enzyme. DNase activity was demonstrated throughout the small intestine and in the large intestine. By the zymogram technique, at least 3 different DNases could be demonstrated in the lower parts of the small intestine, 1 of which could be of extrapancreatic origin.     

Single Cell Protein in the Diets of Pigs and Chickens: Effects on the Activity of Dnase in Intestinal Contents

Pigs and chickens were fed diets containing increased concentrations of the single cell protein (SCP), Pruteen, in order to investigate the effects of a diet containing high levels of nucleic acids on the activity of DNase in intestinal contents. Increased levels of SCP in the diet generally resulted in increased DNase activity in intestinal contents.Significant differences at P≦0.05, were found between the control groups and most of the experimental groups in both species.With the exception of the 2 groups given the highest levels of SCP in the chicken experiment, the DNases in the large intestines were not inhibited by antisera produced against DNase in pancreatic juice.     

Metabolic and anatomical adaptations of heavy-bodied chicks to intermittent feeding. 2. Pancreatic digestive enzymes.

1. Activities of digestive enzymes in meat-type chickens under ad libitum or alternate-day feeding were determined from 14 to 83 d of age. 2. Final body weight of intermittently fed birds attained 75% of that of the ad libitum-fed controls. 3. When compared with the ad libitum-fed counterparts, a marked increase in the relative weight of the pancreas and intestinal contents were found on repletion days. On depletion days the relative weights of the pancreas and of the intestinal contents were about half those found in ad libitum-fed birds. 4. The activity of the digestive enzymes in the pancreas, expressed as U/g pancreas or U/kg body weight, was not affected consistently by the feeding regime. In the small intestine a marked increase in relative activity (U/kg body weight) was observed on repletion days and a marked decrease on depletion days as compared with ad libitum-fed controls. The activities per g intestinal contents following food restoration did not differ significantly from those of ad libitum-fed controls except for trypsin, which was higher in the former. On depletion days the activities per g intestinal contents were lowest, lipase excepted.     

Effects of age and diet on the development of the pancreas and the synthesis and secretion of pancreatic enzymes in the young pig

Effects of age and diet composition on amylase, trypsin and chymotrypsin activities in the pancreas and intestinal contents, pancreas weights and body weights were determined from birth to 56 d. A total of 120 pigs, five to seven pigs/litter from 18 litters, were slaughtered at birth, 14, 27, 29, 31, 42 and 56 d. Litters were allotted to dietary treatments (corn-soy, A; corn-soy + 20% dried whey, B; corn-soy + 5% lard, C) and offered these diets as creep feed at 14 d. All pigs were weaned at 28 d, placed in elevated nursery pens and fed their respective diets. Total activities of amylase, trypsin and chymotrypsin in the pancreas and small intestine increased (P less than .05) with age. Both trypsin and amylase activities, measured per kilogram body weight or gram pancreas weight, were low at 29 d in the intestine and increased to 56 d. Pigs on diet B had the highest level of trypsin and chymotrypsin in the intestinal contents (P less than .05). Trypsin activity in the pancreas (units/kg body weight) was lowest (P less than .05) for pigs on diet B and highest (P less than .05) for those on diet C (units/g pancreas and units/kg body weight). Amylase activity (units/kg body weight) was lower (P less than .05) in the pancreas for pigs on diet B than for those on diets A and C. Pigs on diet A had lower (P less than .01) intestinal amylase activities than those on diets B and C. Enzyme activities in the intestinal contents and pancreas were low following weaning. In the pancreas, activities decreased at 31 d.(ABSTRACT TRUNCATED AT 250 WORDS)     

Activities of amylase, trypsin and lipase in the pancreas and small intestine of the laying hen during egg formation

1. During a cycle of 14 h artificial light and 10 h darkness, dry matter and enzyme concentrations were measured in the pancreas and gut of egg-forming hens. 2. Dry or fresh pancreas weight did not show significant variation but pancreatic enzyme activities increased gradually from 2 to 22 h after oviposition. 3. Total wet and dry matter contents of the small intestine gradually increased from 2 to 18 h after oviposition and then decreased significantly. Intestinal tryptic activity followed the same pattern whereas intestinal amylase gradually decreased from 2 h after oviposition; intestinal lipase activity tended to decrease during the light period (2 to 10 h after oviposition) and to increase during the dark period (14 to 22 h after oviposition). 4. By contrast, patterns of enzyme activity in the pancreas were similar. It is proposed that modification of the chyme and transit rates during the day may affect pancreatic enzyme fate and distribution in the small intestine. 5. In non-egg-forming birds intestinal contents and enzyme activities were less than in egg-forming birds. The reverse was observed in the case of the pancreas where contents and enzyme activities were increased. A relationship with food intake pattern is discussed.     

Isolation and identification of intestinal bacteria from Japanese tree frog (Hlya japonica) with the special reference to anaerobic bacteria.

The bacteria in the large intestines of eight Japanese tree frogs (Hlya japonica) were enumerated by using an anaerobic culture system. The microorganisms at approximately 3.1 x 10(9) bacteria per g (wet weight) of intestinal contents were present in the intestine of all the frogs tested. No difference of the total bacteria in the frog intestine was observed between two different incubation-temperatures (room temperature and 37 degrees C). Eleven genera and 16 species were isolated from the frog intestine. In most frogs, Bacteroides (B.) caccae and B. vulgatus were detected as the predominant organisms. Escherichia coli was also present in greater numbers in the intestine. Other bacteria isolated at high dilutions were strict anaerobes, including Fusobacterium and Clostridium. Enterococcus faecalis was frequently isolated from the frog intestine. However, four genera of Bifidobacterium, Eubacterium, Peptostreptococcus, and Lactobacillus were not isolated from the frog intestine.     

Growth and development of the digestive organs and some enzymes in broiler chicks after hatching.

1. Body weight and the weight of the digestive organs and activities of some digestive enzymes were determined from hatching to 23 d of age. 2. Relative daily growth rate peaked at 11 d of age (22% gain/d) and then decreased gradually. 3. The vitelline residue was decreased rapidly from 4.6 g at hatching to negligible values from 4 d of age. 4. Maximal allometric growth of the pancreas and small intestine was 4-fold and that of liver 2-fold greater than that of the body. 5. Activities (units/kg body weight) of the digestive enzymes measured in the pancreas and intestinal contents increased with age. In the pancreas maximal values were attained on day 8 for amylase and lipase and 11 for trypsin and chymotrypsin. In the small intestine maxima were attained on day 4 for lipase, 11 for trypsin and chymotrypsin and 17 for amylase. 6. The development of secretion of digestive enzymes in the post-hatched chick could be a limiting factor in digestion and subsequently in food intake and growth.     

DNases in milk and blood sera from different species.

DNases were demonstrated in samples of colostrum and blood serum from man and various domestic animals. The measurable DNase activity recorded was highest in samples from cat and dog and lowest in samples from goat, horse, pig and sheep. In contrast to DNases produced by certain bacteria, these enzymes were thermo-labile and the activity was maximal in the area pH 5.0–5.5.A modification of an agar medium originally described for the demonstration of bacterial DNases was found to be suitable for assays of DNases from colostrum, milk and serum.     

Serological Investigations of Leptospiral Deoxyribonucleases

Enzymoserological comparison of a selection of leptospira strains tested with sera from rabbits immunized with unpurified DNase of Leptospira interrogans, serotype canicola, indicates the production of DNase of serologically very similar properties by the serotypes canicola, autumnalis, icterohemorrhagiae and pomona. The DNase produced by serotype hyos was serologically different from the others, while the serotypes grippotyphosa and bataviae did not produce DNases at all. The method used made it possible to differentiate between leptospiral DNase and normally occurring DNases in the serum samples. Neither leptospira DNase nor specific leptospira-DNase-antibodies could be detected in dog sera with high agglutinationlysis titres after natural infection.     

Histological alterations to the pancreas and the intestinal tract produced by raw faba bean (Vicia faba L. minor) diets in growing chicks

1. Inclusion of raw faba bean (Vicia faba L., minor) in the diet of growing chickens was shown to affect the performance of the birds and to produce a significant increase in the relative weight of the pancreas. This was attributable to dietary trypsin inhibitors. 2. Trypsin inhibitors also produced degenerative changes in pancreatic acinar cells. These were observed by light and electron microscopy. 3. Progressive cytopathological changes were observed in the intestinal tract. The duodenum, jejunum and ileum were altered, with extensive erosion, shortening and atrophy of microvilli. 4. The results endorsed previous findings obtained using different legume seed lines (Phaseolus spp). Faba bean produced similar local reactions in the pancreas and the intestine. This may be caused by the presence of lectins in the seeds.     

丁酸梭菌对慢性肾衰竭犬肠道菌群及血清小分子尿毒素含量的影响

本试验旨在研究丁酸梭菌对慢性肾衰竭(CRF)犬肠道菌群及血清小分子尿毒素含量的影响。选取20条2岁左右的雄性贵宾犬,随机分成4组:假手术对照组(CL组)、模型组(MD组)、低剂量丁酸梭菌组(LCB组)和高剂量丁酸梭菌组(HCB组),每组5只。CL组只做腹腔打开手术,其余3组肾动脉结扎制作CRF模型。造模成功后,LCB组和HCB组分别按每天0.5、1.0 g/kg BW的剂量灌喂丁酸梭菌,进行为期4周的干预。检测血清和粪便尿素氮(UN)、肌酐(Cr)和硫酸吲哚酚(IS)含量,并对肠道菌群16S rDNA进行高通量测序。结果表明:1)试验结束时(第4周),LCB组和HCB组的血清UN、Cr和IS含量极显著低于MD组(P<0.01),但极显著高于CL组(P<0.01);与LCB组比较,HCB组的血清UN、IS含量显著降低(P<0.05),血清Cr含量极显著降低(P<0.01)。试验结束时,HCB组的粪便UN、Cr含量均显著低于MD组(P<0.05),CL组的粪便UN、Cr含量均显著低于MD组、LCB组和HCB组(P<0.05)。2)饲喂丁酸梭菌均降低CRF犬肠道菌群的α多样性,HCB组的Chao1指数、Shannon指数显著低于MD组(P<0.05)。主坐标分析(PCoA)结果显示4组样本间发生明显聚类。3)在门水平上,MD组的肠道放线菌门(Actinobacteria)和变形菌门(Proteobacteria)的相对丰度显著高于CL组(P<0.05),LCB组和HCB组的肠道Actinobacteria、Proteobacteria的相对丰度均显著低于MD组(P<0.05);在属水平上,饲喂丁酸梭菌可降低CRF犬肠道变形杆菌属(Proteus)、埃希氏菌属(Esche-richia)、肠杆菌属(Enterobacter)、普氏菌属(Prevotella)、放线菌属(Actinomyces)和涅斯捷连科氏菌属(Nesterenkonia)的相对丰度。LEfSe分析发现,CRF犬肠道菌群有19个具有差异的生物标志物,主要集中于Actinobacteria、Proteobacteria,饲喂丁酸梭菌可减少CRF犬生物标志物的差异。4)Spearman相关性分析显示,血清UN、Cr和IS含量与Enterobacter、Proteus和Escherichia相对丰度存在较强的正相关关系,与乳杆菌属(Lactobacillus)、双歧杆菌属(Bifidobacterium)相对丰度存在较强的负相关关系。由此可见,CRF犬肠道菌群紊乱与血清小分子尿毒素含量之间存在相关性,丁酸梭菌可通过调节CRF犬肠道菌群结构,促进血清小分子尿毒素的清除,以每天1.0 g/kg BW添加量为宜。     

乳鸽早期消化特性研究

试验通过研究2~10日龄乳鸽体重、消化器官重量、血清蛋白质代谢、胰腺和小肠黏膜消化酶活性等指标的变化规律,揭示乳鸽消化道早期发育特性。选取出壳后2、4、6、8、10日龄白卡奴乳鸽30羽(每个日龄6羽),屠宰取样。结果表明:1)日龄对乳鸽早期体重(含卵黄重)、腺胃、肌胃、肝脏、胰腺、小肠的器官重量和器官指数;血清总蛋白、白蛋白、尿酸、尿素氮含量;胰腺淀粉酶、脂肪酶、胰蛋白酶总活性,脂肪酶比活性,小肠黏膜二糖酶(蔗糖酶和麦芽糖酶)及碱性磷酸酶总活性和比活性均影响显著(P0.05)。其中,发育模式随日龄变化表现为线性增加的指标包括:肝脏、胰腺、小肠的器官指数(P0.01);体重,肌胃、腺胃、胰腺、肝脏、小肠的器官重量(P0.01);血清总蛋白和白蛋白含量(P0.01);胰腺淀粉酶、脂肪酶、胰蛋白酶总活性,胰腺脂肪酶比活性(P0.05);小肠黏膜二糖酶(麦芽糖酶和蔗糖酶)和碱性磷酸酶总活性和比活性(P0.01)。血清尿酸、尿素氮含量,胰蛋白酶比活性发育规律表现为线性下降(P0.05)。腺胃和肌胃的器官指数表现为先上升后下降(P0.05)。2)肠段对乳鸽小肠黏膜麦芽糖酶和蔗糖酶总活性影响显著(P0.05)。3)日龄与肠段的交互作用对麦芽糖酶总活性、蔗糖酶总活性和蔗糖酶比活性影响显著(P0.05)。结果提示,随着日龄变化,乳鸽机体蛋白质代谢能力不断增强,沉积水平不断提高,消化系统发育迅速,生长速度高于机体生长,自身胰腺和小肠黏膜水解酶活性不断增强,10日龄时,机体发育水平显著提高。因此,2~10日龄阶段是乳鸽出壳后消化生理机能趋于完善的重要阶段。     

The occurrence of Clostridium perfringens in the intestine of chicks

Commercial broiler chicks brooded either on wire or on used or new litter demonstrated a 75% (62/75) incidence of recovery of "perfringens-like" colonies from the intestine during a 5-week period. Eleven Clostridium spp. were identified from among these "perfringens-like" organisms, which were cultured on SPS selective agar medium. Clostridium perfringens was positively identified only infrequently (five isolates) from among the "perfringens-like" colonies. In contrast, "perfringens-like" colonies were not recovered from the intestinal contents of specific-pathogen-free chicks reared in an isolation unit. However, C. perfringens was isolated from the yolk sac of one embryonated egg and from the intestine of a single 7-day-old chick, indicating the possibility of vertical transmission of this potential pathogen.     

Effect of recombinant DNA-derived bovine alpha-1 interferon on transmissible gastroenteritis virus infection in swine

Recombinant DNA-derived bovine interferon alpha 1-1 (BoIFN) inhibited replication of both vesicular stomatitis virus and transmissible gastroenteritis virus in cultures of swine testicular cells. Newborn pigs were orally inoculated with BoIFN and subsequently had interferon in their gastric contents and serum; however, interferon was found only occasionally in intestinal washings. Incubation of BoIFN with gastric contents from a newborn suckling pig did not affect antiviral activity, whereas intestinal (small intestine) contents from the same animal inactivated BoIFN within 1 minute. Beginning at 6 hours of age, newborn, colostrum-deprived pigs were given 1 mg of BoIFN orally every 12 hours. These pigs were not protected against challenge exposure to virulent transmissible gastroenteritis virus at 48 hours of age; disease and mortality were similar for these pigs and for control pigs not given BoIFN prior to challenge exposure. The BoIFN did not impair growth rate of pigs and did not cause obvious disease or lesions.     

Hemorrhagic enteritis associated with Clostridium perfringens type A in a dog

A female Shetland sheep dog died suddenly with hemorrhagic diarrhea and vomitting, and was examined pathologically and microbiologically. Gross pathological change was restricted to the intestinal tract. The intestine contained watery, blood-stained fluid. Histopathologically, the principal intestinal lesion was superficial mucosal hemorrhagic necrosis at the jejunoileum. Many Gram-positive bacilli were found adhering to the necrotic mucosal surface in parts of the intestinal tract. Clostridium perfringens in pure culture were isolated from jejunal contents by anaerobic culture. These results suggested that the typical lesion of this case coincided with canine hemorrhagic enteritis and enterotoxemia due to C. perfringens infection could be the cause of sudden death.     

Neospora caninum infected the alimentary tract of nude mice and was transmitted to other mice by intraperitoneal inoculation with the intestinal contents

Neospora caninum (BT-2 strain) that originated from the brain of a Holstein calf was serially passaged through 10 generations of BALB/c nude mice by intraperitoneal inoculation. Histological examination of the mice revealed that numerous clusters of tachyzoites appeared in the pancreas, stomach and small intestine as well as in the central nervous system (CNS) and skeletal muscles. Intestinal contents of the infected mice were inoculated intraperitoneally into uninfected nude mice and 3 of the 17 inoculated mice showed clinical signs at post inoculation days 3 to 10. The present experiments demonstrated a proliferation of N. caninum tachyzoites in the mucosa of the alimentary tract and pancreas of the nude mice and the intestinal contents of the mice were infective to other nude mice.     

Clostridial enteric infections in pigs.

Clostridium perfringens types A and C and Clostridium difficile are the principal enteric clostridial pathogens of swine. History, clinical signs of disease, and gross and microscopic findings form the basis for a presumptive diagnosis of C. perfringens type-C enteritis. Confirmation is based on isolation of large numbers of type-C C. perfringens and/or detection of beta toxin in intestinal contents. Diagnosis of C. perfringens type-A infection, however, remains controversial, mostly because the condition has not been well defined and because type-A organisms and their most important major (alpha) toxin can be found in intestinal contents of healthy and diseased pigs. Isolation of large numbers of C. perfringens type A from intestinal contents, in the absence of other enteric pathogens, is the most reliable criterion on which to base a diagnosis. Recently, beta2 (CPB2) toxin-producing C. perfringens type A has been linked to disease in piglets and other animals. However, implication of CPB2 in pathogenesis of porcine infections is based principally on isolation of C. perfringens carrying cpb2, the gene encoding CPB2, and the specific role of CPB2 in enteric disease of pigs remains to be fully defined. Clostridium difficile can also be a normal inhabitant of the intestine of healthy pigs, and diagnosis of enteric infection with this microorganism is based on detection of its toxins in feces or intestinal contents.     

Clostridium perfringens beta2-toxin in an African elephant (Loxodonta africana) with ulcerative enteritis.

A 22-year-old female African elephant (Loxodonta africana) developed diarrhoea of unknown cause which lasted for two days. The animal was euthanased after it remained recumbent and refused to get up. Gross pathological changes were present mainly in the gastrointestinal tract. The intestinal contents were watery and dark brown. Several areas of the mucosa of the small intestine were covered minimally to moderately with fibrin and had a few 0.1 x 10 to 15 cm linear ulcerations. Microscopical lesions consisted of discrete areas of necrosis of the surface and crypt epithelium without overt inflammatory infiltrates. Culture of the small intestinal contents resulted in a moderate growth of Clostridium perfringens. No salmonella were found in the small or large intestine. PCR of the isolate of C. perfringens revealed the presence of the beta2-toxin gene cpb2 and the alpha-toxin gene cpa but no other known toxin genes. The expression of the beta2-toxin gene in vivo was demonstrated by the immunohistochemical localisation of the beta2-toxin to the microscopical lesions in the small intestine.     

The demonstration and characterization of deoxyribonucleases of streptococci group A, B, C, G and L.

Streptococcus pyogenes, S. agalactiae, S. dysgalactiae, S. equi, S. equisimilis, S. zooepidemicus, Streptococcus group G and L were found to produce deoxyribonucleases (DNases) which were demonstrated using the Toluidine Blue DNA Agar (TDA) described for staphylococcal DNases. The activity of streptococcal DNases increased in the presence of Mg⁺⁺ and Ca⁺⁺ ions, the pH optimum was about 7.5 and native DNA was the best enzyme substrate. It is consequently recommended to modify the TDA according to these results for the demonstration of streptococcal DNases. All streptococcal DNases, except the DNase of S. zooepidemicus, were found to be heat-stable. Isoelectric focusing was a convenient technique for separation of streptococcal DNases and for estimation of the pI values of the DNases. S. agalactiae and S. dysgalactiae generally exhibited distinct species specific patterns in the isoelectric focusing experiments. The DNases produced by S. pyogenes were serologically related to the DNases of S. dysgalactiae and Streptococcus group G. A similar relationship was demonstrated between the DNases produced by S. equisimilis and Streptococcus group L.