Effect of supplementation of soy sauce cake and vinegar brewer's cake with total mixed ration silage-based diet on nutrient utilization by Holstein steers

A study was conducted to assess the nutritive value of brewer’s by-product of soy sauce cake (SSC) and vinegar brewer’s cake (VBC) on rumen fermentation both in vitro and in vivo, and digestibility in the duodenum. In the in vitro trial, at first SSC and VBC were evaluated as sole diet compared to concentrate. In the next trial, three kinds of diets, 80% of total mixed ration (TMR) silage + 20% concentrate (Control), 80% of TMR silage + 5% concentrate + 15% SSC (T1), and 80% of TMR silage + 5% concentrate + 15% VBC (T2) on dry matter (DM) basis, were also tested in the in vitro analysis. The ranked orders of in vitro ruminal gas production and volatile fatty acids (VFA) concentrations were concentrate > VBC > SSC and concentrate > VBC ≥ SSC, respectively. Whereas, no differences (p > 0.05) were found in the gas production and VFA concentrations among three diets (control, T1 and T2) when used with TMR silage-based diet. In the in vivo digestibility trial, three Holstein steers cannulated at rumen and duodenum were fed three types of diets as above. DM digestibility in rumen and duodenum as well as in total tract was not significantly different (p>0.05) in three diets. Crude protein intake was significantly higher (p 0.05) among three diets in both rumen and post-rumen. The intake and digestibility of neutral detergent fiber did not differ among the three diets. No differences (p > 0.05) in rumen pH, VFA concentrations or the molar percentage of lactate, acetate, propionate, and NH 3 -N concentration were found among three diets. The concentrations of blood chemical findings were not different (p > 0.05) among three diets. The above data suggest that SSC and VBC have the potential to be used as alternative feed resources for ruminants at 15% on a DM basis.