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PAPER SELECTED

The Effects of Supermethrin on Ammonia-Utilizing Enzymes of Rumen Bacteria

LENARTOVA V, HOLOVSKA K, RYBOSOVA E, JAVORSKY P, LEGATH J
Veterinarni Medicina 38, 1993, 99-106

Synthetic pyrethroids are neuroactive substances with high selectivity to insects. They are fast-degrading and show low toxicity to the other organisms. In spite Of all these characteristics there are certain risks for ruminants in these chemicals because the ruminants as herbivorous animals consume large amounts of plants treated with insecticides. As bacterial microflora plays an important role in ruminant physiology, the effects of supermethrin were investigated in relation to the activity of key enzymes of nitrogen metabolism of rumen bacteria, namely of glutamate dehydrogenase (GDH-NADH E.C.1.4.1.2., GDH-NADPH E.C.1.4.1.4.) and glutamine synthetase (GS E.C.6.3.1.2.). Supermethrin (Czechoslovak product) was administered to 15 sheep of the Slovak Merino breed at the age of eight months, at subchronical doses (50 - 300 mg/kg live weight) for six weeks. Two bacterial fractions were isolated from rumen after sheep slaughter: rumen fluid bacteria and rumen-wall adhering bacteria, in which GDH and GS activities were determined. The activities of these enzymes in eight pure bacterial rumen cultures were investigated to determine the effects of supermethrin on the different bacterial strains: S. ruminantium A 17, F succinogenes 16 J, B. ruminicola 3/3, M. elsdenii 4 MJ, L. plantarum MRS, S. bovis A 24, S. xylosus 3 1 0 and E. faecium 2. The bacteria were cultivated in media with supermethrin additions at concentrations of 0.66


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