Resumo

COSTA, E.C.B. et al. Effect of various salt concentrations on the ruminal parameters of goats. S. Afr. j. anim. sci. [online]. 2020, vol.50, n.4, pp.635-642. ISSN 2221-4062.  http://dx.doi.org/10.4314/sajas.v50i4.15.

The objective of this study was to evaluate the effects of various concentrations of sodium chloride (NaCl), magnesium chloride (MgCl₂), and calcium chloride (CaCl₂) on the growth and in vitro fermentation of cellulolytic, glycolytic, and amylolytic microorganisms from the rumen of a goat. Six concentrations of each salt were tested separately, namely 0 mg/dL, 100 mg/dL, 200 mg/dL, 400 mg/dL, 800 mg/dL, and 1600 mg/dL in the culture medium. The experiments were conducted in a completely randomized design, in a 6 x 3 factorial arrangement of salt concentration and substrate (starch, cellulose, and glucose) with three replications of each treatment combination. Concentrations of microbial protein, ammonia (NH₃-N), and volatile fatty acids (acetate, propionate, and butyrate) were measured. A quadratic effect of CaCl₂ concentration on the production of microbial protein was observed in the cellulose medium. The effect of MgCl2 on NH3-N production in the cellulose medium decreased linearly. Propionate concentration decreased linearly with increasing levels of NaCl and MgCl2 in the media containing starch. There was a decreasing linear effect of MgCl₂ on the concentration of butyrate in the media containing glucose. In conclusion, concentrations of NaCl and CaCl2 up to 1,600 mg/dL did not affect the microbial activity of starch, cellulose, and glucose-fermenting organisms. However, the microbial activity of starch-fermenting microbes was inhibited at salt concentrations above 800 mg/dL. Thus, brackish water could be used by goats in semiarid regions, but its use should be managed carefully so that it does not have a negative impact on rumen microbial populations.

Palavras-chave : cellulose; glucose; saline water; starch; ruminants.

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