Effect of sodium, calcium, processed, and natural bentonites on ruminal ammonia nitrogen concentration using in vitro methods

Bentonite is a combination of aluminosilicate which has a high capacity to adsorb toxins such as aflatoxins and other substances (Magnoli et al. 2010). Many researchers have used this substance as a mineral to control and balance pH of rumen (Bringe and Schultz 1969; Rinsig et al. 1969; Britton et al. 1978). It is identified with a clay composition that 90% of which contains montmorillonite (Aghashahi et al. 2005). It has a high absorption property due to the presence of negative charges on the surface of clay materials (Aghashahi et al. 2005). Bentonite is used for different purposes such as performance improvement of male calves (Aghashahi et al. 2005), reduce radiocaesium contamination of soil (Vandenhove et al. 2005), organic modification for the adsorption of organic contamination (Sreedharan and Sivapullaiah 2012) and improvement the strength properties of dry pellets (Timofeeva and Nikitchenko 2014). The physical and chemical structure of bentonite, allows it to superficially absorb proteins and amino acids (Fenn and Leng 1989). This property of bentonite is hypothesized to protect the proteins and amino acids from microbial fermentation occurring in the rumen. On the other hand, ion exchange attribute makes ammonium ions and cations exchanged (Fenn and Leng 1989) and then, it prompts a more optimized use of rumen microorganisms for microbial protein synthesis, by gradually discharging ammonium ions (Nikkhah et al. 2001). Many commercial bentonites produce in Iran, but their benefits for ruminants is unknown; so, this experiment was conducted to evaluate the effect of sodium, calcium, processed and natural bentonites on ammonia nitrogen concentration using in vitro methods.
Material and At the first experiment, ammonia nitrogen concentration was compared in a medium containing natural and processed (mass percent of sulfuric acid to bentonite was 10, 15 and 20) bentonites after 4 and 24 h incubation. The culture medium was prepared according to Menke and Steingass (1988) and Theodorou et al (2001). Ammonia nitrogen concentration was determined according to kjeldahl (Mojtahedi and Danesh Mesgaran 2011). Rumen fluid was collected via fistula of three Baluchi male sheep. Bentonite samples were processed and acivated with sulfuric acid and temperature. Applied feed in this culture medium was composed of ground barley (50%), urea (40%) and processed bentonite (10%). At the second experiment, the effect of adding sodium or calcium bentonite on ammonia nitrogen concentration at different incubation time in a culture containing feed rations with different rumen degradability was investigated. The crude protein was similar between treatments with different ruminal degradability (12.02 vs. 15.15). The culture medium was prepared just as experiment 1 with different feed ingredient (table 1). Bentonite samples were taken from Vivan Company. Sodium bentonite was composed of 69%SiO2, 11.71% Al2O3, 0.04% BaO, 1.56% CaO, 1.99% Fe2O3, 1.13% K2O, 1.82 MgO, 0.04 MnO, 3.08 Na2O, 0.08% P2O5, 1.17 SO3, 0.16 TiO2, 0.01> Cr2O3, 8.22% LOI and calcium bentonite was composed of 64.63%SiO2, 10.02% Al2O3, 0.06% BaO, 4.68% CaO, 2.21% Fe2O3, 0.4% K2O, 1.5 MgO, 0.05 MnO, 2.1 Na2O, 0.08% P2O5, 2.31 SO3, 0.3 TiO2, 0.01> Cr2O3, 11.66% LOI.
At the first experiment, the ammonia nitrogen concentration was affected by the treatments after 4 h incubation (p Generally, the results indicated that the ammonia nitrogen concentration was affected by the processing procedure of bentonite and sodium or calcium bentonites and the highest ammonia nitrogen absorption was observed at the first incubation times (2 and 4 h). It seems that sodium bentonite compared to calcium bentonite can be more effective in ammonia nitrogen adsorption.