Influence of Metal Ions on Ruminal Enzyme Activities

Abstract

In vitro incubation experiments were conducted to evaluate the influence of several metal ions on urease, alanine aminotransferase (ALT), aspartate aminotransferase (AST), gammaglutamyltransferase (GGT) and glutamate dehydrogenase (GDH) enzyme activities of rumen fluid. Rumen fluid was collected from eight fistulated ewes and strained through a cheesecloth. Magnesium, copper and cadmium were each added to 10 ml of rumen fluid to obtain final concentrations of 5 mmol . l -1 . After the addition of each metal ion, the mixture was shaken and incubated for 30 min at 37 °C prior to enzyme activity assay in the rumen fluid with or without metal ions using spectrophotometric methods. Cadmium was found to inhibit urease, GDH, and GGT activity but on the other hand, it stimulated ALT and AST activity. Copper inhibited both GDH and urease activity with no significant differences for ALT, AST and GGT. Magnesium had stimulatory effect on activity of GGT and GDH. The results of this experiment indicate that metal ions copper, cadmium, and magnesium each affect some ruminal enzyme activity which play an important role in metabolism of nitrogenous substances and may further alter the nitrogen metabolism in the rumen of sheep. , cadmium, magnesium, ruminal enzyme, nitrogen metabolism, rumen, urease Nutritional requirements of ruminants are different from those of monogastric animals. Rumen microbes can synthesize enough amino acids and peptides from the inorganic nitrogen in ammonia or other nitrogen source and carbon skeletons and sulphur precursors. Ammonia assimilation by rumen microbes depends on rumen pH (Veth et al. 1999), rumen ammonia concentration (Mehrez et al. 1977) and ruminal ammonia-assimilating enzyme activity. CopperSeveral ammonia-assimilation reactions by rumen bacteria are known. Enzyme glutamate dehydrogenase plays an important role in maintaining the balance between ammonia-and α-amino-nitrogen of the rumen. Alanine represents the amino acid found in the highest concentration in the intracellular pool of free amino acid rumen bacteria. Rumen bacteria possess effective mechanisms for alanine synthesis from ammonia (e.g., alanine dehydrogenase and alanine aminotransferase). Both alanine aminotransferase and aspartate aminotransferase belong to the most common transaminases in the rumen. Glutamate concentration by rumen bacteria depends on gamma-glutamyltransferase activity. This enzyme plays an important role in some peptide and amino acid tranfers through the rumen wall and in the formation of an intracellular pool of glutamate as well.In the recent past, factories producing copper and mercury have altered the agricultural environment. Jenãík et al. (2001) reported that soil and plant biomass sample analyses from localities situated maximally 10 km from the copper and formerly mercury producing factories showed significant soil and biomass contamination by mercury, lead, cadmium, copper, and zinc ions. Magnesium-processing industry pollutes its surounding by magnesium fly ash which may increase the risk ...

Tolerance of a ruminant ciliate Entodinium caudatum against mercury, copper and chromium

“…Sensitivity of rumen bacteria to heavy metals ranges in large scale depending on bacterial species and conditions with consequences on their metabolic activity (Forsberg 1978;Legáth et al 1990;Lauková 1994;Lenártová et al 1998;Faixová & Faix 2002). In comparison with our resultsE.…”

Effects of dietary addition of zinc and(or) monensin on performance, rumen fermentation and digesta kinetics in beef cattle

“…Hence, several other additives that could be used to manipulate fermentation of dietary substrates by rumen microbes are currently under study. Various metal ions could affect rumen fermentation (Martínez et al, 1970;Spears and Hatf ield, 1978;Rodríguez et al, 1995;Arelovich et al, 2000;Faixova and Faix, 2002). Previous research indicated that dietary addition of 250 to 400 mg Zn kg -1 DM to low-quality forage altered rumen fermentation by retarding ammonia accumulation and increasing molar proportions of propionate (Arelovich et al, 2000).…”

“…Alfalfa (Medicago sativa L.) hay and barley (Hordeum vulgare L.) grain are common ingredients used for growingfinishing diets in beef cattle. Animal performance on this type of diet could be increased by the addition of Zn in the diet (Arelovich et al, 2000;Faixova and Faix, 2002;Bateman II et al, 2004). One of the advantages of using Zn as an additive is that various inorganic Zn salts can be easily obtained in the market, and usually they have a lower cost when compared to monensin or similar feed additives.…”

Influence of different sources of zinc and protein supplementation on digestion and rumen fermentation parameters in sheep consuming low-quality hay

“…However, high levels of Zn in lambs could have protecting effect from Cu depletion originated in high levels of Cd in the diet. Also Zn not retained in the animal and excreted could be a potential hazard in areas that are already contaminated by heavy metals (Faixova and Faix, 2002). Any way in this study the levels of Zn supplied by treatments were much lower than previously studied when proposed as an additive to manipulate rumen fermentation.…”

“…A recent review discusses progress in decreasing rumen methane through different additives by rumen microbial manipulation (Kobayashi, 2010). Some essential elements could also impact on rumen microbial fermentation as well (Martinez and Church, 1970;Spears and Hatfield, 1979;Rodriguez et al, 1995;Arelovich et al, 2000;Faixova and Faix, 2002;Arelovich et al, 2008;Richter, 2011). Previous research indicated that dietary addition of 250 to 400 mg Zn kg −1 DM to low-quality forage supplemented with urea retarded ammonia accumulation and increased molar proportions of propionate in beef cattle (Arelovich et al, 2000).…”