Resumo

GIGER-REVERDIN, S. et al. Effect of live yeast culture supplementation on rumen fermentation in lactating dairy goats. S. Afr. j. anim. sci. [online]. 2004, vol.34, n.5, pp.59-61. ISSN 2221-4062.

Addition of yeast to dairy cow diets might be beneficial for milk production. However, data concerning goats are scarce, especially on the role of yeast on rumen metabolism. Thus, four goats, according to a cross-over design, received successively two diets with or without living yeasts. Animals were in mid-lactation and received a total mixed diet ad libitum. For the yeast diet (Y), each goat received 5 g of Saccharomyces cerevisiae CBS 493.94 twice a day. Samples of ruminal content were taken every two hours for eight hours after the morning feeding. Yeast addition did not have any statistical effect either on feeding pattern or on concentrations of volatile fatty acids, ammonia, lactate or soluble carbohydrate in ruminal fluid. The pH was numerically higher for the yeast diet compared to the control. Ruminal buffering (BC) capacity of the Y diet was significantly higher than that of the control. The BC increased as pH decreased. Dietary effects and ruminal soluble carbohydrate concentrations explained part of the residual of the equation linking buffering capacity and pH. Yeast addition also avoided some lactate peaks in the first hours of fermentation. This experiment clearly pointed out that the Saccharomyces cerevisiae CBS 493.94 yeast has an effect on ruminal metabolism when considering its BC and might have a smoothing effect on the appearance of lactate peaks or on a decreased pH. These effects are of particular interest for those diets which might induce acidosis such as some diets rich in rapidly fermentable energy given to high producing dairy goats in early lactation.

Palavras-chave : Saccharomyces Cerevisiae yeast; rumen digestion; buffering capacity; dairy goats.

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