Effect of β-carotene on selected indices of in vitro rumen fermentation in goats

Abstract

Three goats fi tted with rumen fi stula were used as donors of rumen fl uid. Substrates were incubated in vitro with buffered rumen fl uid for 24 h. Different levels of β-carotene (fi ve groups: 10, 50, 100, 200, 500 mg/l) were added as fi ve treatment groups to determine whether it affected rumen fermentation in vitro as compared with blank samples used as controls. NH 3-N concentrations with 50, 100 and 200 mg β-carotene/l group were found signifi cantly lower than that in blank samples (P<0.01). Microbial protein concentrations in all β-carotene-added groups were higher than in blanks, while those found in 200 and 500 mg/l groups were signifi cantly higher (P<0.05 and 0.01, respectively). Total VFAs seemed not to be affected by added β-carotene (P>0.05), although propionate and butyrate concentrations changed. It is concluded that β-carotene can enhance the utilization of NH 3-N by rumen microorganisms and thus promote their growth in vitro.