In vitro study of the effect of corn dried distillers grains with solubles on rumen fermentation in sheep

The aim of the in vitro study was to determine the effect of corn dried distillers grains with solubles (corn DDGS), used as a replacement for the concentrate ingredients of sheep diet, on rumen fermentation. The material for the study was the ruminal fluid of Polish Merino sheep which was incubated during 4-, 8- or 24-hour periods. Five groups of samples were prepared for in vitro fermentation: C – control, incubated with the substrate consisting of the concentrate ingredients; D1, D2 and D3, where DDGS was used as a substrate added in proportions of 10, 20 and 30% of dry matter of the concentrate; and D4, where 100% DDGS was used as a substrate. After fermentation, the gas and short chain fatty acids (SCFAs) analyses were performed using gas chromatography. The ammonia concentration and pH were also determined, and the SCFA utilization index (NGR), the fermentation efficiency (FE) and the index of cell yield of ruminal microorganisms (CY) were calculated. This research showed no effect of DDGS on the methane emission. The positive correlations between the amount of methane and ammonia concentrations in the 8- and 24-hour fermentation periods were found. DDGS addition increased propionate proportion, but decreased production of acetate (p<0.01). Additionally, D1, D2, D3 and D4 substrates lowered isobutyrate (p<0.05) and isovalerate (p<0.01) production. Based on the results obtained, it can be stated that partial substitution of the concentrate ingredients with DDGS did not have deleterious effect on sheep rumen fermentation processes.