پديد آورندگان :
خباز سيرجاني، مرتضي دانشگاه فردوسي مشهد - دانشكده كشاورزي , طهماسبي، عبدالمنصور دانشگاه فردوسي مشهد - دانشكده كشاورزي - گروه علوم دامي , ناصريان، عباسعلي دانشگاه فردوسي مشهد - دانشكده كشاورزي - گروه علوم دامي , كرمانشاهي، حسن دانشگاه فردوسي مشهد - دانشكده كشاورزي - گروه علوم دامي , كاظمي، محسن مجتمع آموزش عالي تربت جام - گروه علوم دامي , ابراهيمي خرم آبادي، الياس مجتمع آموزش عالي تربت جام - گروه علوم دامي , اسكندري تربقان، آمنه دانشكده علوم پزشكي تربت جام - گروه مهندسي بهداشت محيط
چكيده لاتين :
Introduction: 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 methods: 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.
Results and discussion: At the first experiment, the ammonia nitrogen concentration was affected by the treatments after 4 h incubation (p<0.05) as, the highest and lowest concentrations were observed in 15 (mass percentage of acid to bentonite: 15; ammonia nitrogen: 6.09mg/dl) and 20 % (mass percentage of acid to bentonite: 20; ammonia nitrogen: 7.15 mg/dl), respectively. It was reported reported that when sodium bentonite (SB) was added to the diet of Angora goats at 2.5 and 5 %, ammonia nitrogen concentration of the rumen fluid was reduced (Mohsen and Tawfic 2002). When the ratio of nitrogen to energy increases in the rumen, ammonia nitrogen production increases subsequently (Hammond 2006). Thus, bentonite with regards to it’s ammonia nitrogen adsorption (Nikkhah et al. 2001), seems to be necessary for adsorption of surplus nitrogen produced in the rumen. The protein degradability in the rumen is one of the most important parameters affecting the supplying of amino acids to the small intestine; whereas, proteolysis determines the accessibility of ammonia nitrogen, amino acids, peptides, and branched-chain fatty acids in rumen microbial protein synthesis (Stern et al. 1994). In the second experiment, ammonia nitrogen concentration of rations with high degradability protein was affected by the treatments at 2 and 4 h after incubation (P<0.05) as, the lowest and highest values were belonging to 2 % sodium bentonite and control treatment, respectively. Ammonia nitrogen concentration in the diet with low digestible protein was also affected by the treatments after 4h incubation (P<0.05). According to Abdullah et al (1995), applying 2 % of bentonite in the sheep diet reduced ammonia nitrogen of rumen fluid, relative to the control group. It was also reported that the extra ammonia nitrogen was absorbed to the blood through the rumen wall and transferred into the liver and was finally transformed to urea; a process which reduces the ammonia nitrogen harmful effects on the animals (Hammond 2006). Moreover, the liver is able to synthesize urea from the NH3, which is released from amino acids as a result of post-rumen digestion and also deamination process. The urea can be excreted through the urine or reabsorbed into the rumen. Thus, there is a strong relationship between ammonia nitrogen and blood urea nitrogen (Hammond 1983). So, application of bentonite in the diets can affect the control of the released nitrogen in the rumen and finally the blood urea nitrogen (BUN) concentration.
Conclusion: 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.
