Abstract:The protection of human health as well as the quality and safe food assurance becomes the priority of European research in the sphere of animal production. The negative experiences with the using of antibiotic growth promoters lead to subsequent reduction of their application. It is necessary to replace them by the growth promoters of natural origin, which are able to provide the comparable efficacy and will not contribute to the cumulative contamination of the environment. The probiotics represent an effective alternative to antibiotics and current research should be aimed at improving of their efficacy. This may be achieved by several methods. From the practical point of view, combination with synergistically acting components of natural origin seems to be the best way. Potentiated probiotics are defined as biopreparations containing production strains of microorganisms and synergistically acting components of natural origin which exert their intensified effect through effects on probiotic and gut microorganisms, the gut mucosa and the intestinal environment or immune system. A number of suitable components may be used for this purpose, such as prebiotics, non-specific substrates, plants and their extracts, metabolites of microorganisms and polyunsaturated fatty acids. In this report, the results of application of natural feed additives in animals are reviewed and their valuation for the enhancement of probiotic effectiveness is discussed.

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We developed a new HPLC method for the determination of p-aminobenzoic acid (PABA) and its metabolites (p-aminohippuric acid, N-acetyl-p-aminohippuric acid, N-acetyl-p-aminobenzoic acid) in urine. As the internal standard m-hydroxybenzoic acid was used. In the isocratic elution the mobile phase consisted of methanol and 0.02 M ammonium acetate (20:80 v/v, pH 4.0). The separation was carried out on the C18, reversed-phase column, particle size 5 microns. The separated components were detected at 280 nm. The method can be used in the assessment of the response of pancrease (secretion of digestive enzymes) to soya feeding as well as in the diagnosis of the exocrine pancreatic diseases of animals.

Oral administration of oil with an increased content of omega-3 polyunsaturated fatty acids to germ-free piglets resulted in a significant increase in the total values of CD4, CD8 lymphocytes, B lymphocytes, and monocytes, in peripheral blood in comparison with the controls. The metabolic activities of phagocytes as well as the polyclonal activation of lymphocytes were not significantly influenced. The level of growth factor was significantly higher, as determined on the basis of somatomedin in the blood serum. Biochemical indices showed a significant increase in the level of eicosapentaenoic and docosahexaenoic acids in blood serum and the decrease in the level of arachidonic acid at the same time.

Observations were carried out of the interactions between Lactobacillus casei 294/89 and enterotoxigenic Escherichia cofi CCM 612 (OlOl:K99) in uivo. In gnotobiotic lambs, inoculation with enterotoxigenic E. coli (ETEC) resulted in diarrhea with a typical clinical picture and patho-anatomical findings. E. coli adhered to the mucosa of the digestive tract at counts amounting to IO5 per cm2. In these lambs, disturbances of intestinal biochemical processes became evident; proteolytic enzyme activity was significantly reduced. Preventive administration of Lactobacillus cusei inhibited the negative effects of ETEC in gnotobiotic lambs, minimized the clinical signs to those of a very moderate diarrhea in the first 12 h after inoculation and significantly reduced the patho-anatomical findings. Enterotoxigenic E. coli counts decreased by 99.1 and 76% on days 2 and 4 after inoculation respectively, and amounted to lo3 per cm'. The inhibitory effects of L. casei against E. coli were most obvious in the jejunum and ileum. The numbers of adhering E. cofi increased from the duodenum with the length of the gut. ETEC counts in the digestive tract of lambs that had been preventively treated with L. casei amounted to 10' ml-'. It can be assumed that, in addition to competitive exclusion, the inhibitory effect of L. casei upon ETEC adherence was also mediated by a Lactobaciflus-produced substance that inhibited E. coli adhesion to the gut mucosa.