Influence of Salix babylonica extract in combination or not with increasing levels of minerals mixture on in vitro rumen gas production kinetics of a total mixed ration

Abstract

The aim of this study was to determine the effects of increasing levels of two feed additives composed of Salix babylonica (SB) extract and minerals mixture (MM) or their combination on in vitro gas production (GP) and dry matter (DM) degradability of total mixed ration (TMR; 50 concentrate: 50 corn silage, on DM basis). Combinations of four levels of SB extract (0, 0.6, 1.2 and 1.8 mL/g DM) with four levels of MM (0, 0.5, 1.5 and 2.5 g/100 g DM) were evaluated in a completely random design. Samples of TMR (1 g) were weighed in 120 mL serum bottles with addition of SB extract and/or MM. Then, 10 mL of particle free ruminal fluid were added followed by 40 mL of the buffer solution. The GP was recorded at 2, 4, 6, 8, 10, 12, 24, 48 and 72 h of incubation. Addition of SB extract, without MM, increased (P<0.05) asymptotic GP (mL/g DM), the rate of GP (/h), GP and DM degradability (DMD).