Das Ziel dieser Studie war, die Wirkung der aktiven Immunisierung gegen das Gonadotropin Releasing Hormon (GnRH) bei männlichen Schweinen zu untersuchen und mit der chirurgischen Kastration zu vergleichen. Ferkel wurden randomisiert und in zwei Gruppen unterteilt: 263 Tiere für die chirurgische Kastration (SC) und 270 für die Immunokastration (IC). Der chirurgische Eingriff wurde in den ersten 14 Lebenstagen durchgeführt und die Impfung mit Improvac®, CSL, Australia, zweimal im Abstand von 4 bis 5 Wochen; die zweite Impfung (Booster) erfolgte 4 bis 7 Wochen vor dem geplanten Schlachttermin. Bei der Schlachtung wurde das Hodengewicht gewogen und Fettproben für die Bestimmung von Androstenon gesammelt. Zusätzlich wurde Androstenon auch olfaktorisch nach Erhitzung der Speicheldrüsen im Mikrowellenofen getestet. Weiter wurden die Tageszuwachsrate und Fleischqualität aller Tiere bestimmt. Die durchschnittliche Androstenon-Konzentration im Rückenfett beider Gruppen (SC und IC) wies keine signifikanten Unterschiede auf (0.042 (0.041; 0.044) µg/g vs. 0.058 (0.044; 0.071) µg/g; Durchschnitt (95 % Konfidenzinterval). Das Hodengewicht von immunisierten Ebern war signifikant (P<0.001) kleiner (230.8 (218.23; 243.52) g) als bei normalen Ebern gleichen Alters (761.8 (722.77; 801.01) g). In dieser Studie konnte bewiesen werden, dass die Androstenon Produktion in allen geimpften Tieren deutlich gehemmt war und alle Schlachtkörper konsumtauglich waren. Der durchschnittliche Tageszuwachs war zwischen SC (0.817 (0.804; 0.830) kg) und IC (0.827 (0.814; 0.840) kg) nicht signifikant verschieden, obwohl letztere Gruppe eine bessere Zuwachsrate zeigte. Der Magerfleischanteil war bei IC (54.50 (54.26; 54.73) %) im Vergleich zu SC (53.76 (53.53; 54.00) %) signifikant (P<0.001) erhöht. Aus unseren Ergebnissen kann gefolgert werden, dass die Impfung gegen GnRH eine praktische und effiziente Methode ist, um die Androstenon Synthese erfolgreich zu unterdruecken. Angst und Stress, die vor allem bei der chirurgischen Kastration auftreten, können auf diese Weise vermieden werden. The objective of this study was to investigate the efficacy of active immunization against gonadotropin releasing hormone (GnRH) in male pigs and to compare it with surgical castration. Piglets were randomly assigned to two groups, one of 263 animals for surgical castration (SC) and one of 270 animals for immunocastration (IC). Surgery was done at 14 days of age and vaccination (Improvac®, CSL, Australia) performed twice at an interval of 4 to 5 weeks with the second injection given 4 to 7 weeks before slaughter. At slaughter, testes were weighed and fat samples collected for androstenone analysis. Androstenone was tested olfactorially by heating salivary glands in a microwave oven. Daily growth rate and meat quality were assessed in all animals. Regarding mean androstenone concentrations in backfat, no significant difference was found between SC and IC (0.042 (0.041; 0.044) µg/g vs. 0.058 (0.044; 0.071) µg/g; mean (95 % confidence interval)). Testes weight was signific...

The microsporidial species Enterocytozoon bieneusi is found among immunocompromised, particularly HIV-infected, patients with chronic diarrhoea, and rarely also among immunocompetent persons with self-limited diarrhoea. Only recently, E. bieneusi was detected in 4 pigs in Switzerland raising the question of a potential zoonotic nature of this parasite. We examined faecal samples of 109 pigs, 24 cows, horses and red foxes each for the presence of E. bieneusi by PCR and compared these isolates with isolates obtained from stool samples of 13 HIV-infected patients living in Switzerland. In animals, E. bieneusi was only identified in pigs with a prevalence of 35%. Analysis of the rDNA internal transcribed spacer (ITS) sequence allowed the classification of E. bieneusi from 28 pigs into 4 distinct genotypes which grouped very closely (identity 96.3-98.8%) together with 2 of the 3 human-derived E. bieneusi genotypes. Hence, E. bieneusi seems to be a common parasite in swine, but no genotypes were identified that were found in humans. Nevertheless, swine might serve as a new animal model for enterocytozoonosis.

Susceptibility to enterotoxigenic Escherichia coli with fimbriae F4ac is dominantly inherited in the pig. A three-generation pedigree was created to refine the position of F4acR on chromosome 13 comprising 202 pigs: eight parents, 18 F1 and 176 F2 pigs. The 17-point analysis indicates that F4acR lies between Sw207 and S0283. Recombinant offspring specify that the most probable order is Sw207-S0075-F4acR-Sw225-S0283. We observed six phenotypes for the three fimbrial variants F4ab, F4ac and F4ad. The two missing phenotypes F4abR-/F4acR+/F4adR+ and F4abR-/F4acR+/F4adR- indicate that pigs susceptible to F4ac are always susceptible to F4ab. Furthermore, a weak and a strong adhesion of F4ab and F4ad bacteria was observed. The weak receptor F4abR (F4abRw) was present only in pigs devoid of the receptor F4acR (F4abR+/F4acR-). In contrast, in pigs with the phenotype F4abR+/F4acR+, F4ab bacteria adhered to the majority of enterocytes. F4abRw constitutes a frequently observed phenotype whose inheritance is still unclear. Strong adhesion of F4ab and F4ac bacteria is most likely influenced by the same receptor that we name F4bcR. The number of F4ad bacteria that adhered to enterocytes was very variable in the adhesion test. Moreover, expression of F4adR was independent of age. Our segregation analyses indicated a dominant inheritance of F4adR, although the number of susceptible pigs was smaller than expected. We examined four genes as candidates for the F4acR locus: the transferrin receptor gene (TFRC) and three genes members of the glucosyl/galactosyltransferase family (B3GnT5, B3GALT3 and B4GALT4). Comparison of sequences from resistant and homozygous susceptible F4ac pigs did not reveal any causative single nucleotide polymorphism in the four genes. Two silent mutations at the positions 295 (C/T) and 313 (T/C) in B3GALT3 were found. Using the somatic cell hybrid panel, B3GnT5 and B3GALT3 were assigned to the chromosomal region SSC13q23-q41. No mutations were found in the cDNA sequences of these genes associated with the F4acR genotypes.

The aim of this study was to refine the localization of the receptor locus for fimbriae F4ac. Small intestinal enterocyte preparations from 187 pigs were phenotyped by an in vitro adhesion test using two strains of Escherichia coli representing the variants F4ab and F4ac. The three-generation pedigree comprised eight founders, 18 F1 and 174 F2 animals, for a total of 200 pigs available for the linkage analysis. Results of the adhesion tests on 171 F2 pigs slaughtered at 8 weeks of age show that 23.5% of the pigs were adhesive for F4ab and non-adhesive for F4ac (phenotype F4abR+/F4acR-; R means receptor). Pigs of this phenotype were characterized by a weak adhesion receptor for F4ab. No pigs were found expressing only F4acR and lacking F4abR. Receptors for F4ab and F4ac (F4abR+/F4acR+) were expressed by 54.5% of the pigs. Animals of this phenotype strongly bound both F4ab and F4ac E. coli. In the segregation study, the serum transferrin (TF) gene and 10 microsatellites on chromosome 13 were linked with F4acR (recombination fractions (theta) between 0.00 and 0.11 and lod score values (Z) between 11.4 and 40.4). The 11-point analysis indicates the F4acR locus was located in the interval S0068-Sw1030 close to S0075 and Sw225, with recombination fractions (theta) of 0.05 between F4acR and S0068, 0.04 with Sw1030, and 0.00 with S0075 and Sw225. The lack of pigs displaying the F4abR-/F4acR+ phenotype and the presence of two phenotypes for F4abR (a strong receptor present in phenotype F4abR+/F4acR+ and a weak receptor in phenotype F4abR+/F4acR-) led us to conclude that the receptor for F4ac binds F4ab bacteria as well, and that it is controlled by one gene localized between S0068 and Sw1030 on chromosome 13.

Summary Immunohistological Determination of Chlamydia psittaci/pecorum and C. trachomatis in the Piglet Gut The jejunum, ileum, caecum and colon of 200 piglets were investigated immunohistochemically for the presence of Chlamydia psittaci and C. trachomatis using a vitelline IgY. Positive samples were later labelled using a commercial C. trachomatis polyclonal antiserum. Chlamydia were present in 33 (16.4%) of the animals, and 30 out of 33 were labelled by C. trachomatis polyclonal antiserum. Inclusions occurred predominantly (67%) in the large intestine. The serological results (CFT, ELISA) did not correlate well with immunohistochemical labelling in the gut. The incidence of Chlamydia rose from 6.9% in animals up to 4 weeks, to 41.8% in those over 4 weeks of age. A correlation between chlamydia and enteric disease was not obvious. Besides chlamydia, most of the diseased animals harboured other additional agents. In conclusion, intestinal chlamydiae in piglets, predominantly C. trachomatis, exist in Switzerland, although their pathogenic potential seems to be low. Zusammenfassung Därme (Jejunum, Ileum, Zaekum, Kolon) von insgesamt 200 Ferkeln wurden immunhistologisch auf Chlamydien untersucht. Der Chlamydien‐Nachweis erfolgte mittels der Avidin‐Biotin‐Methode. Als primärer Antikörper wurde ein aus dem Eidotter von mit C. psittaci und C. trachomatis immunisierten Hühnern gewonnenes Vitellinimmunglobulin IgY und ein kommerzieller polyklonaler Antiserum gegen C. trachomatis verwendet. Insgesamt 33 (16,4%) Schweine erwiesen sich als Chlamydienträger, 30 von 33 beherbergten C. trachomatis. Chlamydien‐Einschlüsse fanden sich überwiegend im Dickdarm (67%). Bei Tieren über 4 Wochen wurden Chlamydien häufiger nachgewiesen (41,8%) als bei Tieren bis zu 4 Wochen (6,9%). Die Ergebnisse der serologischen Untersuchung korrelieren nicht eindeutig mit den immunhistologischen Befunden im Darm. Ein eindeutiger Zusammenhang zum Durchfallgeschehen konnte nicht festgestellt werden, da mit Ausnahme von zwei Fällen bei den an Durchfall erkrankten Ferkeln neben Chlamydien auch andere darmpathogene Erreger gefunden wurden. Die vorliegenden Untersuchungen zeigen, daß auch in der Schweiz latente Darminfektionen mit Chlamydien bei Ferkeln und Läufern vorkommen, und dass Chlamydien als alleinige Durchfallerreger für Schweine vermutlich nur eine geringe Pathogenität aufweisen.