A dose-response investigation on the level of resistance to pyrantel citrate in nodular worms of pigs

This study was undertaken to determine the level of resistance against pyrantel citrate in strains of Oesophagostomum quadrispinulatum and Oesophagostomum dentatum which have previously been found resistant to this anthelmintic. Groups of pigs were artificially infected with batches of infective larvae which were previously found either susceptible or resistant to pyrantel citrate. After treatment with 1, 2 and 4 times the recommended dose (14 mg kg-1) of pyrantel citrate, the resistant O. quadrispinulatum population was reduced by 51.0, 76.2 and 86.1%, and O. dentatum by 41.2, 47.9 and 78.5%. The results indicated that O. dentatum was slightly more resistant (P less than 0.05) than O. quadrispinulatum to pyrantel citrate. Treatment of the susceptible worms with 1 and 2 times the recommended dose caused a reduction in worm numbers by 61.0 and 99.4%, respectively.     

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).     

The synergism of Actinobacillus pleuropneumoniae and influenza A virus in experimentally-infected mice

Models for infecting mice with Influenza A-Virus (A/PR 8/34, H0N1) and Actinobacillus pleuropneumoniae (serotype 9) were developed in Han: NMRI-mice. After infecting mice with sublethal doses of one of the infectious agents, or both together as a mixed infection, animals were subsequently exsanguinated and the lungs washed by bronchoalveolar lavage. Clinical symptoms were recorded daily, examination of lung lavage fluid and sera as well as histology of the lungs were done. An increase in mortality, weight reduction and total cell yield of lung lavage fluid was observed after mixed infection. Compared to mixed infections total protein content and elastase in sera and lung lavage fluid after singular ones were raised not as much. In lung lavage fluid the total cell yield was increased more marked. These alterations indicate a synergistic effect of viruses and bacteria, developed by mixed infection as well as a bacterial infection on top of a viral one. Histopathologically the lung alterations were found to depend on the infectious agent and the mode of infection.     

Examination of pork quality using passive electric methods]

Passive electrical values of 76 probes of pig M. long. dors. with different quality are derterminated. It appears, that a factor (P = value), exactly ascertained from electrical parameters, is fit to characterize the quality of pork. The P-value is theoretical established and has relations to the stability of the membrane structures.