Changes of amino acid concentrations in bacteria adhering to the rumen epithelium in sheep given extremely low oral doses of mercury
1990
Legath, J. | Kacmar, P. | Tomas, J. (Vysoka Skola Veterinarska, Kosice (CSFR))
The effect of low concentrations of mercury taken in the diet (4 mg per head and day) on the amino acid composition in the proteins of rumen bacteria adhering to the dorsal and ventral parts of the rumen was studied in six sheep. Though the mercury did not influence the amino acid concentration in hydrolyzates of epimural bacteria, low-mercury doses caused significant changes of some amino acids, as compared with the control group of animals. The levels of alanine, histidine, threonine, serine and glycine were significantly decreased and at the same time the levels of proline, valine, isoleucine, lysine and phenylalanine were significantly increased. It was stated in our experiment that levels of histidine, alanine and threonine in hydrolyzates of epimural bacteria of the rumen were significantly decreased both in the sheep given the balanced feed ration with additions of mercury and nitrogen (according to the standard) and in the sheep given a low-nitrogen diet. Similarly, the levels of proline and phenylalanine in the hydrolyzates of epimural bacteria in rumen were significantly increased both with the low-nitrogen diet and in the normal nitrogen diet with mercury supplement. The results suggest that unexplained disorders frequently occurring in the microbial synthesis in the rumen might be caused by long-continued administration of feed contaminated with extremely low concentrations of heavy metals. The problem deserves detailed investigation in future studies, oriented to explaining the biosynthesis disorders in rumen, reducing the production ability of ruminants.
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