Efeito de diferentes concentrações de sais sobre os parâmetros ruminais de bovinos e caprinos

Abstract

The objective was to evaluate the effect of sodium chloride (NaCl), magnesium chloride (MgCl2) and calcium chloride (CaCl2) different concentrations on the electrical conductivity, growth and fermentation of cellulolytic, glycolytic and amylolytic bacterias, resulting from cattle and goats. Were used cattle and goats rumen liquid, from rumen cannulated animals to obtain the inoculum. Was evaluated six levels of NaCl, MgCl2 and CaCl2 (0 mg/dL, 100 mg/dL, 200 mg/dL, 400 mg/dL, 800 mg/dL and 1600 mg/dL) and three substrates (starch, cellulose and glucose) in a completely randomized delineation in a factorial 6 x 3 to microbial growth parameters determination. In the cattle experiments, was obtained a CaCl2 quadratic effect levels on microbial protein concentration in the starch medium, and an MgCl2 quadratic effect in the cellulose medium. Occurred a quadratic levels effect of NaCl, MgCl2 and CaCl2 on the microbial protein concentration in glucose medium. While acetate concentrations decreased linearly with the increase of NaCl in starch, cellulose and glucose containing medium. Was obtained a quadratic effect to starch and cellulose medium, above the propionate concentrations in NaCl levels. However in goat experiments the microbial protein concentrations increased linearly with NaCl, MgCl2 and CaCl2 increasing levels, in starch medium. Occurred a quadratic effect of CaCl2 concentration on the microbial protein in cellulose medium . However, at CaCl2 levels on N-NH3 concentration existed a linear increasing effect for starch. Regarding MgCl2, happened a linear effect on the NH3 concentration in cellulose medium. Was observed a quadratic effect levels of NaCl in starch containing medium on the acetate concentration. There was a decreasing linear effect of CaCl2 levels in cellulose containing medium on the acetate concentration. Was obtained a NaCl and MgCl2 linear effect levels in starch containing medium on propionate concentration. Was obtained a NaCl, MgCl2 and CaCl2 linear decrease levels in starch containing medium on the butyrate concentration and was MgCl2 declining linear effect on glucose containing medium. Concluding that the bovine bacteria in NaCl presence above of 400 mg/dL reduced the cellulose fermenting bacteria efficiency. While glucose fermenting bacteria are tolerant to NaCl concentrations supporting levels of up to 800 mg/dL and the amylolytic bacteria tolerate levels up to 1600 mg/dL. However, the MgCl2 salt at levels of 1600 mg/dL does not affect the efficiency of starch and glucose fermenting bacteria, on the other hand, the cellulose fermentative bacteria have shown to be less tolerant to levels above 400 mg/dL. xiv However, the CaCl2 at the level of 1600 mg/dL does not affect the efficiency of starch, cellulose and glucose microbial fermenting bacteria. However, the goats bacteria in the constitution of NaCl salt to 1600 mg/dL does not affect the efficiency of starch, cellulose and glucose microbial fermenting bacteria. At the same way MgCl2 did not affected the cellulose and glucose fermenting microbial efficiency at the level up to 1600 mg/dL. However, the microbial efficiency of starch fermenting bacteria is inhibited at levels above 800 mg /dL. The CaCl2 up to 1600 mg /dL does not affect the microbial efficiency of starch, cellulose and glucose fermenting bacteria.