| Summary: | The aim of this research was to evaluate the effect of the inclusion of <i>Acacia mearnsii</i> (AM) at different levels of inclusion on ruminal digestion and in vitro gas production. <i>A. mearnsii</i> forage was incorporated in the diet at different levels of 0 (AM0), 20 (AM20), and 40 (AM40) %. In situ degradation of dry matter (DM) and organic matter (OM) showed differences between treatments (<i>P</i> < 0.05), obtaining the highest value of the degradation of soluble fraction (A), insoluble but potentially degradable fraction (B), degradation rate in % per hour (c), potential degradation (A + B), and effective degradation for all passage rates in % h (0.02, 0.05, and 0.08) in AM0 with respect to AM20 and AM40. The in vitro digestibility of DM and OM was higher (<i>P</i> < 0.05) in AM0 with approximately 23.6% and 22.8% of DM and OM, respectively, compared to treatments AM20 and AM40. Cumulative gas production (PG) and gas production asymptote (B) were lower at AM0 and AM20 <i>versus</i> AM40; however, gas production rate (c) and total CH<sub>4</sub> production were lower at AM40 with about 40.1 mL CH<sub>4</sub>/0.500 g fermented DM <i>versus</i> AM0 and AM20. Under the conditions of this study, it is concluded that the incorporation of <i>A. mearnsii</i> (20% and 40%) in the feed of ruminants negatively affected the digestion of nutrients; however, it reduced the production of CH<sub>4</sub>, which may be associated with the low activity of microorganisms toward the substrate due to the possible tannin/nutrient complex. This shows that in animals with little history of consuming plants rich in tannin, more than 3% of tannin could not be incorporated into the diet.
|
|---|
