Postruminal Delivery System for Amino Acids and Proteins in Cattle

The purpose of this experiment was to develop an effective postruminal transport system (PTS) with a high content of suitable vegetable proteins and amino acids. PTS serves for nutrient delivery to the abomasum and small intestine of dairy cows in order to increase the milk yield. Direct addition of proteins and amino acids to the diet is not useful as the ruminal microbes will utilize active substances before they reach absorption sites in the small intestine. PTS has several advantages, e.g. a possibility of the direct application in a food, low cost, and nutritional and therapeutical improvement. PTS consists of a core (pellets, small tablets) and a coating, which protects the core against the environment of rumen and enables to release the core content in the environment of abomasum and small intestine. Lenticular tablets - cores of PTS were prepared by wet granulation method and compression. Qualitative indicators of tablets (average weight, weight uniformity, hardness, friability, disintegration time) were determined according to valid Czech and European Pharmacopoeias. Cores were subsequently coated with several types of coating - ethylcellulose, stearic acid and pH sensitive polymer poly-(2-vinylpyridine-co-styren), alone or in combination of various rates. Nine samples of coated protein tablets exhibiting appropriate characteristics in vitro were prepared. The presence of the pH sensitive polymer at least in 10% concentration of the coating and the coating amount of 9.0 to 12.6% per tablet were necessary to ensure the requested PTS properties

Zinc and Cadmium Toxicity Using a Biotest with Artemia franciscana

Of the various toxic elements heavy metals, particularly cadmium, lead, mercury and zinc, occur frequently in the environment due to their relatively high industrial use. While the toxicity of individual substances is usually well known, information about their mutual interactions is relatively scarce. In animal experiments the prevailing trend is to substitute higher vertebrates with biotests of the 2nd generation. Our experiment focused on observation of the effect of combinations of ZnSO4.7H2O and CdCl2.2H2O on lethality to Artemia franciscana. The aim of the study was to observe the synergistic or antagonistic effects of these two metals. Depending on concentration, cadmium may increase or decrease the toxicity of zinc. at higher concentrations of CdCl2.2H2O exceeding 100 mg l-1 one can observe obvious synergistic toxic effects of both the substances. Our observations allowed us to conclude that the use of optimum, relatively low concentrations of cadmium (up to 50 mg l-1 CdCl2.2H2O) results in a significant decrease in lethality to Artemia franciscana caused by ZnSO4.7H2O at concentrations of 50, 100 a 250 mg l-1