Influence of virginiamycin on the digestive physiology in precaecal re-entrant cannulated pigs.

The present experiment was set up to study the effect of Virginiamycin, a nutritional growth promoting antibiotic, on the digestive physiology using precaecal cannulated pigs. The semipurified diet used provided 21% protein and 60% of nitrogen free extract (NFE), 2/3 as starch and 1/3 as lactose. Due the older age of the pigs, the lactose induced some degree of malabsorption as precaecal flow rate of digesta was markedly higher (3.2 kg/d) compared with published data obtained with purified diets without lactose. This was also reflected in the rather low ileal digestibility of the nutrients (%): dry matter 68.6, protein 79.6, fat 78.4 and NFE 75.0. Virginiamycin markedly lowered flow rate (2.2 kg/d) and significantly improved apparent precaecal digestibilities (%): dry matter 74.0, protein 81.4, fat 81.9 and NFE 78.7. The faecal apparent digestibility was comparable with published data. There were no treatment differences indicating that precaecal digestibilities are much more sensitive then faecal ones. In order to explain the differences obtained the mean retention time in the upper intestine was measured. Although significant differences were noted (control: 5 h, Virginiamycin: 6 h) a direct cause-effect relationship was not evident. Also the activity of selected pancreatic enzymes in ileal contents was compared. There were no consistent differences between the two treatments, except for a lower lipase activity during Virginiamycin treatment.

[Ureolytic activity in the intestinal tract of layers, effects of bacitracin and flavomycin (author's transl)]. / L'activité uréasique de la flore du tractus digestif de la pondeuse, effet de la bacitracine et de la flavomycine.

Counting of bacteria, detection of urease-positive bacteria and estimation of bacterial ureolysis influenced by Bacitracin and Flavomycin was done on intestinal contents from different segments of the digestive tract of laying hens. It was concluded that: - the intestinal flora was numerically most important in the caecum and was composed principally of lactobacilli in the crop, gizzard, duodenum, jejunum and ileum, and of lactobacilli and anaerobes in the caecum and colon. - 17% of the total number of intestinal bacteria were urease-positive. - the ureolytic activity was most important in the caecum: 24 mg of urea hydrolysed/g of contents during 4 hours of incubation. The range is between 2 and 4 mg in the other segments. - until the level of 500 ppm, Bacitracin and Flavomycin did not influence the in vitro ureolytic activity of fecal and cecal material.

Occurrence of megasphaera elsdenii in faecal samples of young pigs.

Important numbers of Megasphaera elsdenii, known as a normal inhabitant of the rumen of cattle and sheep were recently cultured from intestinal contents of man and pigs. Studying the occurrence of this organism in faecal contents of pigs, we paid attention to the use of a strict anaerobic isolating and counting technique. It was demonstrated that Megasphaera elsdenii is a strict anaerobic organism. Exposure to air during 15 minutes caused an important decrease of the colony count. Comparison of the biochemical properties of some isolates with the data of other investigators is given. Pigs isolates were nearly similar to rumen strains.

Comparison of three techniques for the total count of anaerobes from intestinal contents of pigs.

For the total count of anaerobes from cecal and colon contents of pigs, the roll-tube method of Hungate, the anaerobic ringed-plate technique of Van der Heyde, and incubation of petri dishes in anaerobic jars were compared.