Abstract

Effects of various metal cations and physical methods of feed processing with different intervals of exposition of ruminal fluid with feed factor were assessed in the experiment by method of biotesting. Recombinant E. coli strain with cloned luxCDABE-genes Photobacterium leiognathi, ruminal fluid of beef cattle of Kazakh white-headed breed, model ruminal fluid and trophic substrates were used in the study. It had been established that iron ions at 6 h of incubation had a sharp increase of toxicity level of mixture; it was visualized with reduction of bacterial luminescence in comparison with the same system of 3 h incubation. Cupric copper ions showed much less toxic properties emerging only 6 h of incubation and demonstrating decrease of bacterial luminescence only by a few percents. The impact of physical factors by means of preliminary treatment by super high frequency waves or ultrasound formed a significant increase in toxicity during the first hours. Calcium cations had a positive effect on luminescence of recombinant E. coli strain. So, biotesting allows to determine biotoxicity of ruminal fluid with regard to feed components, degree of biosensors viability.