In vitro gas production and dry matter degradability of diets consumed by goats with or without copper and zinc supplementation.

ABSTRACT

An in vitro gas production technique was used to evaluate the effects of copper and zinc supplementation on the amount and rate of gas production, dry matter degradability (IVDMD), utilization of metabolizable energy (ME), and ruminal fermentation patterns using rumen fluid from four Boer male goats as inoculum. The goats were fed twice daily at 0700 and 1900 h a total mixed ration containing 10.3 and 22.5 mg/kg DM of Cu and Zn, respectively. This diet was incubated in vitro for 96 h with four treatments being control, Cu (21.7), Zn (5.6), and Cu-Zn (21.7 and 5.6) which was provided as a mineral premix. Data were analyzed as a completely randomized design. Rates of gas production (RGP) at 4 (RGP(4h)) and 6 h (RGP(6h)) and gas production (GP) at 24 (GP(24h)) and 48 h (GP(48h)) differed (p < 0.01) among treatments. An addition of Cu increased the RGP(4h), RGP(6h), GP(24h), and GP(48h) (p < 0.0001). The Cu treatment had the highest IVDMD and control the lowest (p < 0.05), and the Cu treatment was the highest values of ME and SCFA. The addition of Cu to the in vitro ruminal fermentation increased gas production and efficiency of energy use.