In vitro, the sensitivity to different propolis extracts, at a concentration of 100 mg/ml, of Staphylococcus aureus, Staphylococcus sp. coagulase negative, Streptococcus agalactiae and bacteria of the coliform group, isolated from the milk of cows with mastitis, was evaluated using the technique of an agar disk diffusion with a medium doublelayer. The results showed that the commercial propolis, the ethanolic extract, and, in a minor proportion, the methanolic extract inhibited the growth of the Gram positive bacteria, Staphylococcus aureus, Staphylococcus sp. coagulase negative and Streptococcus agalactiae. The extracts obtained through water, etila acetate and chloroform did not inhibit any bacterial strains, nor did the pure ethanol and methanol vehicles that were utilized as controls. The Gram negative bacterium tested, from the coliform group, did not show sensitivity to any extract. Bacterial strains of the same species collected from different sources presented significant differences in sensitivity to the extracts (p < 0.05). In the Streptococcus agalactiae samples, the diameters of the zone of inhibition around the disks were bigger than those observed for samples of Staphylococcus aureus and Staphylococcus sp. coagulase negative. The results of this experiment stimulate the continuation of studies on the use of propolis extracts, by means of using the appropriate vehicles for the treatment of bovine mastitis. | A sensibilidade, in vitro, de amostras de Staphylococcus aureus, Staphylococcus sp. coagulase negativos, Streptococcus agalactiae e bactérias do grupo dos coliformes, isoladas do leite de vacas com mastite, a diferentes extratos de própolis, na concentração de 100 mg/ml, foi avaliada pela técnica do antibiograma em discos de papel de filtro com sobrecamada de meio de cultura. Os resultados mostraram que o extrato etanólico de própolis comercial, os extratos etanólico e, em menor proporção, o metanólico inibiram o crescimento das amostras de bactérias Gram-positivas, Staphylococcus aureus, Staphylococcus sp. coagulase negativos e Streptococcus agalactiae. Os extratos obtidos através da água, do acetato de etila e do clorofórmio não inibiram nenhuma amostra bacteriana, assim como os veículos etanol e metanol puros utilizados como controle. A bactéria Gram-negativa testada, do tipo coliforme, não apresentou sensibilidade a nenhum dos extratos. Verificaram-se diferenças significativas (p < 0,05) na sensibilidade aos extratos entre amostras bacterianas de uma mesma espécie, mas de origens diferentes. Nas amostras de Streptococcus agalactiae, os diâmetros dos halos de inibição do crescimento bacteriano ao redor do disco foram maiores que aqueles observados para as amostras de Staphylococcus aureus e Staphylococcus sp. coagulase negativos. Todos estes resultados estimulam o prosseguimento de novas pesquisas sobre a utilização de extratos de própolis, em veículos adequados, com vistas ao tratamento da mastite bovina.

In the conditions of the Republic of Belarus there was determined the influence of multi-enzymatic veterinary drug preparations Vitazim (contained a complex of enzymes of carbohydrases: xilanase; cellulose; beta-glucanase) and Ehkosim (universal multi-enzymatic complex: beta-glucanase; endo-xilase; and cellulase) on microbial composition of intestinal bacterial population. Research was realized by an example of layer hens of four-linear cross Highsex white at the age of 34-51 weeks. Regimens of administration of the analyzed preparations were presented. Research results showed promoted the development of the regenerative process of physiological media in intestines of poultry which was necessary for subsisting of normal flora of pathogenic bacteria. The studied preparations Vitazim and Ehkosim can be applied for the preventive treatment and therapy of intestinal dysbacteriosis, normalization of its microbial flora, as well as for the antibacterial therapy.

Studying of efficiency of application of a natural biological control agent BioLAD obtained as a result of cultivation of Fusarium sambucinum fungus in feeding of broiler chickens was realized in the conditions of the Republic of Belarus. There were studied 100 broiler chickens of Ross-308 cross. Broiler chickens of the first (control) group were fed with standard diet with PK-5-1. Broiler chickens of the experimental groups starting from one day old age till the end of the growing period (41 days old) were fed with feed supplement BioLAD in different doses: 0,25 ml/head (second group), 0,5 ml/head (third group), 1 ml/head (fourth group). Research results showed that natural biological control agent BioLAD in dose of 0,5 ml/head made it possible to increase chicken live weight on 11,2 %, viability - on 4,2%. Feeding charges per 1 kg of live weight gain were1,89 kg (second group), 1,81 kg (third group), 1,90 kg (fourth group). It made it possible to decrease the combined feed charges on 6,4% (second group), on 10,4% (third group), and on 5,9% (fourth group). Application of biological control agent BioLAD had an effect on poultry growth activity, promoted high level of chickens viability, increased the indices of general and local protection, stimulated metabolic processes