Prove di tossicità da S C P nell'ovino: nota 7.: rilievi sul comportamento della microflora ruminale

During chronic and acute toxicity trials on ovines, fed with an alkanegrown SCP, observations were also made on the behaviour of the ruminaI microflora. The different diet supplied to both experimental and control groups of animals, did not seem to have affected the total count and the total numbers of Starch digesters, Cellulose digesters and Proteolytic bacteria. During the chronic toxicity test, 194 strains of yeast were identified belonging to the following species:Candida boidinii, Candida slooffii, Candida tropicalis, Cryptococcus albidusvar.albidus, Cryptococcus albidusvar.diffluens, Cryptococcus dimennae, Cryptococcus kuetzingii, Rhodotorula glutinisvar.dairenensis, Rhodotorula glutinisvar.glutinis, Rhodotorula graminis, Rhodotorula pallida, Rhodotorula rubra, Torulopsis versatilis, Trichosporon cutaneum, Debaryomyces hansenii, Debaryomyces phaffi, Debaryomyces tamarii, Saccharomyces vafer. The yeast species that were isolated were not so different from those discovered by other authors in similar researches, carried cut, however, in animals fed differently. A marked diffusion of the genusDebaryomyceswas to be observed, together with a notable lipolytic and caseinolytic activity in most of the strains isolated. At first the introduction of SCP in the diet at concentrations of 15% and 40% seemed to favour the multiplication of the yeasts in the rumen fluid, but their numbers diminished towards the end of both test in all groups under observation. The type of protein given, does not seem to have affected even the species of yeasts that are usually lodged in the animals rumen. Screening of the isolated strains is now in course for the SCP production on glucose, lactose, xylose, starch, fruit and citrus pulps, and other conventional substrata.