Influence of zinc bacitracin and Bacillus licheniformis on microbial intestinal functions in weaned piglets.

The influence of zinc bacitracin (ZB) and of Bacillus licheniformis on host microbial-related functions in young piglets was investigated by applying the concept of microflora-associated characteristics. Six biochemical parameters were determined before and after weaning in faecal samples from piglets in four litters having access to a diet containing ZB, to a diet containing B. licheniformis, to a diet with both additives, or to a diet with no additives, from 3 weeks of age. Statistically significant differences were found in three of the intestinal functions investigated: formation of short-chain fatty acids (at 7 and 10 weeks of age). degradation of mucin (at 7 and 10 weeks of age) and conversion of bilirubin to urobilins (at 7 weeks of age). We also found age-dependent influences on the formation of short-chain fatty acids, on conversion of cholesterol to coprostanol and on conversion of bilirubin to urobilins. We conclude that a functional approach is appropriate for measuring exogenous influence(s) on the microbial intestinal metabolisms in weaned piglets.

Influence of bacitracin on microbial functions in the gastrointestinal tract of horses.

This study investigated the influence of zinc bacitracin on the intestinal flora of horses. The functionally active intestinal flora was examined in 6 horses during treatment with zinc bacitracin. Utilising gas chromatography, spectrophotometry, gel electrophoresis and paper chromatography, samples were analysed on biochemical markers reflecting the action of parts of the intestinal flora. The following 5 flora-related functions were studied in faecal samples and intestinal samples from different sections of the hindgut: conversion of cholesterol to coprostanol and of bilirubin to urobilinogens, degradation of mucin and of beta-aspartylglycine and inactivation of tryptic activity. Conversion to coprostanol, conversion to urobilinogens and degradation of mucin were affected by treatment of zinc bacitracin and conversion to coprostanol was most sensitive. All functions were normalised in a short time, in contrast to man and rats. Differences in environmental exposures are probably the reason for a more rapid normalisation of the intestinal flora functions in horses.

The absorption and distribution of 14C-bacitracin in rainbow trout (Salmo gairdneri) after a single oral dose, as observed by whole body autoradiography.

This study was performed to investigate the absorption, distribution and elimination of orally given radiolabelled bacitracin methylene disalicylate (BMD) in rainbow trout kept in salt water. The level of radioactivity in skeletal muscle tissue remained low, but stable throughout the experiment, while radioactivity in bile and liver tissue increased for about 48 hr, before decreasing. There was a trapping of BMD and/or its metabolites in excretory kidney tissue, where the amount of radioactivity continued to increase when radioactive material was being removed from other tissues. The maximum concentration found in excretory kidney tissue was about 7 times as high as the maximum concentration found in the liver. Even though there is no appreciable absorption of BMD from the gastrointestinal tract in homoiotherms, we found the absorption in rainbow trout to be significant.

Distribution and placental transfer of trichlorfon in guinea pigs.

Radiolabelled trichlorfon, dimethyl-(2,2,2-trichloro-1-hydroxyethyl)phosphonate, was administered by stomach tube to pregnant guinea pigs on days 37 and 52 of gestation and examined by the whole body autoradiography method. The results showed that the radiolabelled compound was rapidly distributed to the main organs of the dam with the highest concentrations in the liver, the kidney and the lung. No substantial concentration of radioactivity occurred in the fetuses until 30 min after administration. The uptake in the fetuses was more pronounced at the later gestational stage when the concentration in the fetal liver equalled that of the placenta.

Prenatal effects of trichlorfon on the guinea pig brain.

The organophosphorus compound trichlorfon, dimethyl (2,2,2-trichloro-1-hydroxyethyl) phosphonate, was administered by stomach tube (100 mg/kg) to pregnant guinea pigs at two different stages of gestation (days 36, 37, 38 and 51, 52, 53). The pups developed locomotory disturbances, and post mortem examination revealed significantly decreased weights of the total brain and the cerebellum, as compared to controls. There was also a significant weight reduction particularly of the medulla oblongata, but also of the hippocampus, the thalamus, and the colliculi. Histological examination of the cerebellum revealed reduction of the external granular layer and the molecular layer, and regional absence of Purkinje cells. The activities of the neurotransmitter enzymes choline acetyltransferase (ChAT), and glutamate decarboxylase (GAD) in cerebellum were reduced as compared to the control values.

[Clinical effects of ivermectin in the treatment of Sarcoptes scabiei var canis in farm foxes]. / Klinisk effekt av ivermectin ved behandling av Sarcoptes scabiei var canis på farmrev.

The efficacy of ivermectin against natural infection of the mange mite Sarcoptes scabiei var canis in foxes was evaluated. The investigations consisted of two field studies and one controlled study. In experiment 1, ivermectin was given as a single subcutaneous dose at 200 micrograms/kg in six foxes. In experiment 2, was one group, consisting of five animals, administered 200 micrograms ivermectin/kg s.c. twice with an interval of 35 days. Group two, consisting of four animals, was given one subcutaneous injection of 400 micrograms ivermectin/kg. In experiment 3, ten foxes were given 1 ml 0.2% Eqvalen s.c. (i.e. 340-440 micrograms ivermectin/kg). A control group of ten animals was not medicated. Before and after treatment a clinical evaluation and skin scraping for microscopic examination was carried out in all three experiments. The results indicated that ivermectin was a good alternative in the therapy of the Sarcoptes mange in foxes by moderate mite infection. A progressive clinical improvement of the mange lesions was evident in the treated foxes. Mites were not detected in skinscraping, except in one animal in experiment 3. It was concluded that ivermectin should be administered, in an initial dose of 400 micrograms/kg and a repeated dose of 200 micrograms/kg 2-3 weeks after the first treatment.