Three strains of streptococcus bovis were isolated from the ruminal contents of sheep and cattle: SbS45 from a sheep; Sb-Cl8 and Sb-CS from different steers. All the strains were found in large number(more than lo* per ml) in the rumen fluid samples after the animals were overfed with wheat and the acute lactic acidosis occurred, but the strains presented only in small numbers ranging from lo4 ...

The use of antibiotics for animal growth promotion has been controversial because of the potential transfer of antibiotic resistance from animals to humans. Such transfer could have severe public health implications in that treatment failures could result. We have followed a risk assessment approach to evaluate policy options for the streptogramin-class of antibiotics: virginiamycin, an animal ...

From Streptomyces virginiae, in which production of streptogramin antibiotic virginiamycin M(1) and S is tightly regulated by a low-molecular-weight Streptomyces hormone called virginiae butanolide (VB), which is a member of the gamma-butyrolactone autoregulators, the hormone biosynthetic gene (barS1) was cloned and characterized by heterologous expression in Escherichia coli and by gene disrup...

Three trials were conducted with 252 pigs to determine the effects of the dietary additions of Cu (250 ppm as copper sulfate), with and without sulfide (500 ppm as ferrous sulfide), and antibiotics (55 ppm chlortetracycline or 27.5 ppm virginiamycin) on the performance and liver Cu stores of growing-finishing pigs. Single additions of Cu, chlortetracycline or virginiamycin to a 16% protein, cor...

the aim of this study was to compare the effects of three antibiotic alternatives with a control (antibiotic-free) and an antibiotic diet on performance and gut morphology of broilers reared on litter. 600 day-old ross-308 chicks were assigned to 48 pens in a crd design with 6 × 2 factorial arrangements, in which 2 levels of chick density (5 and 7.5 chicks/m2) and 6 experimental diets (control,...

Virginiamycin M (VM) of Streptomyces virginiae is a hybrid polyketide-peptide antibiotic with peptide antibiotic virginiamycin S (VS) as its synergistic counterpart. VM and VS belong to the Streptogramin family, which is characterized by strong synergistic antibacterial activity, and their water-soluble derivatives are a new therapeutic option for combating vancomycin-resistant Gram-positive ba...

The use of additives in ruminant diets has occurred more intensely recent years to increase animalperformance, through changes the ruminal microbiota. Thus, this study aimed evaluate: 1) Isomix (Iso)and virginiamycin (Vir) concentrate, a 2x2 factorial (without and with 30 g Isomix/cow/day; without 210mg virginiamycin/cow/day), on productive performance mixed cows pasture; 2) multiplesupplement ...

the objective of the study was to compare the effects of antibiotic virginiamycin, probiotic protexin® and plantago major l. (plantain) on performance, serum metabolites, immune response, and the ileal microbial population of broilers. the experiment was carried out with a total of 200 day-old male ross 308 broiler chickens in a completely randomized design. chickens were allocated to five grou...