Deoxyribonuclease Inhibitory Activity in Pig Intestinal Contents

The inhibitory effect of pig intestinal contents on some microbial DNases and bovine pancreas DNase was examined employing an agar diffusion test. The molecular weight of 1 inhibitor as well as the electrophoretic patterns of the inhibitors were determined. DNases from Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Clostridium perfringens and bovine pancreas were inhibited by intestinal contents. DNases from Clostridium septicum, Serratia marcescens, Proteus mirabilis, Aeromonas hydropnila and Pseudomonas aeruginosa were not inhibited. The concentrations of the inhibitory substances were considerably higher in contents from the small intestine than from the large intestine. Using electrophoretic procedures on intestinal contents, 3 different fractions showing DNase inhibition were demonstrated. The molecular weight of one of the inhibitors was estimated to be about 30000.     

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.     

Fimbriae in Escherichia Coli Isolated from the Small Intestine of Piglets

Ninety E. coli strains, isolated from piglets which had died from neonatal diarrhea, were tested for the presence of K88, K99, 987P and type 1 fimbriae. Two or more types of fimbriae were demonstrated in 14 of the strains, a single fimbria! type in 44 strains while in 32 strains no fimbriae were detected. Of the 14 E. coli strains with more than 1 type of fimbriae, 12;, 10, 8 and 4 strains showed K88, K99, 987P and type 1, respectively. Twelve E. coli strains were isolated from piglets which had died in the neonatal period without showing signs of neonatal diarrhea at necropsy. One strain showed 987P and 3 strains showed type 1 fimbriae, while the remaining 8 strains were unfimbriated. Sixteen fimbriated E. coli strains were subcultured in order to examine the stability of fimbrial expression in the strains. The K88 and the type 1 fimbriae were regularly expressed, while the K99 and 987P were inconsistently demonstrated.     

Drug Resistance in Strains of Escherichia Coli Isolated from the Intestinal Tract of Pigs in Norway

Faecal samples from 95 healthy pigs and samples of jejunal content from 85 piglets suffering from colienterotoxaemia were tested for the presence of drug resistant E. coli strains. Practically all pigs in both groups harboured E. coli strains resistant to one or more of the 6 antibiotics/chemotherapeutic agents tested (Oxytetracycline, streptomycin, sulphaisodimidin, neomycin, ampicillin, chloramphenicol). Almost 100% of healthy and approx. 90% of diseased pigs harboured strains resistant to Oxytetracycline, streptomycin and sulphaisodimidin. Pigs with strains resistant to neomycin, ampicillin and chloramphenicol were less frequently found. The predominant coliform flora consisted of E. coli strains” resistant to Oxytetracycline, streptomycin and sulphaisodimidin in 71% to 81% of diseased pigs and in 47% to 69% of the healthy pigs. In diseased pigs ¾ of the animals had a coliform flora dominated by neomycinresistant E. coli strains. Of the 721 resistant E. coli strains isolated from healthy pigs, 11% were single resistant while the corresponding figure for the 518 resistant strains isolated from diseased pigs was 6%. Thus 89% and 94% of strains showed simultaneous resistance to 2 or more antibiotics. E. coli strains resistant to 3 or more drugs were found in approx. 60% and 70% of the isolates from healthy and diseased animals, respectively. Oxytetracycline/streptomycin/sulphaisodimidin resistance was most commonly found, approx. 22% and 38% of the strains from healthy and diseased pigs, respectively, showing this resistance pattern. Transmission of drug resistance which was examined in E. coli strains originating from the diseased pigs was demonstrated in approx. 76% of the isolates. The incidence of drug resistance transfer in single, double, triple and quadruple resistant strains was 11%, 68%, 97% and 98%, respectively.     

Single Cell Protein in the Diets of Pigs and Chickens

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.     

Proteinase,Lipase and Amylase Activities in the Small Intestine of Pigs Suffering from Colienterotoxaemia

The activities of proteinases, lipases, amylases and the activities of proteinase inhibitors, as well as the numbers of Escherichia coli in the contents from the small intestine were examined for pigs suffering from colienterotoxaemia and for healthy pigs. Enzyme activities were determined using an agar diffusion test. Compared with healthy animals the activities of proteinases and amylases in diseased animals were reduced while lipases showed increased activity. In pathologically changed contents showing large numbers of E. coli, proteinases could not be demonstrated; however, proteinase inhibitors were found in these contents. In healthy animals, proteinase inhibitors were not demonstrated in ingesta-con-taining contents. In diseased animals, E. coli were found in large numbers in all parts of the small intestine. In healthy animals, E. coli was demonstrated especially in the posterior part of the small intestine and regularly in small numbers. The possible influence of digestive enzymes, especially proteinases and their inhibitors, on enterotoxins from E. coli is discussed.     

Infection with Actinobacillus Suis in Pigs

Actinobacillosis in pigs seems to be relatively rare and when it does occur, it usually manifests itself as acute septicaemia during the first weeks of life (Zimmermann 1965). Polyarthritis, pneumonia and heart lesions as well as petechial haemorrhages in skin, viscera and kidneys are also frequently found (MacDonald et al. 1976, Jones & Simmons 1971). Both Actinobacillus suis and Actinobacillus equuli have been isolated from such cases (Pedersen 1977).