The effects of kefir addition on fermentation characteristics, aerobic stability, and in vitro digestion properties of white clover silages

The aim of the present thesis was to examine the impact of kefir yeast on fermentation characteristics, aerobic stability, nutritive value, in vitro digestibility, some micro- and macronutrient concentration, and fatty acid composition of white clover silages. White clover silages were either uninoculated (Con) or inoculated with kefir yeast at the following application rates: 10 mg/kg (K10), 50 mg/kg (K50), 100 mg/kg (K100) on a fresh basis, and ensiled in laboratory-scale silos for 270 d, followed by 5 d of aerobic exposure. Changes in fermentation characteristics and nutritive value, in vitro digestibility and gas production, mineral concentrations, and fatty acid composition were assessed in terminal silages. The results showed that kefir yeast could effectively reduce neutral detergent fiber, hemicellulose, and ammonia-N contents. The increased acetic acid content of kefir yeast treated silages improved aerobic stability. Kefir yeast made no significant difference in cumulative gas production and estimated parameters except for 48 and 72 h. This study has also shown that kefir yeast reduced the potassium, sodium, selenium, and boron concentrations of white clover silages, whereas calcium, zinc, and iron concentration increased. In addition, kefir yeast significantly increased the proportion of saturated fatty acid in white clover silages, whereas the proportion of polyunsaturated fatty acid decreased. However, kefir yeast had no significant effect on the monounsaturated fatty acid proportion of white clover silages. Overall, it is concluded that adding 50-100 mg/kg of kefir yeast on a fresh basis is appropriate to improve the nutritional value of white clover silage.