Abstract:
The objective of this study was to evaluate pattern of fresh cassava root fermentation to develop as protein source on nutritive values and to evaluate effects of level of yeast (Saccharomyces cerevisiae) -fermented fresh cassava root (0, 10, 20 and 30% dry matter) in concentrate diet on dry matter intake (DMI) and nutrient digestibility. This study was separated into 2 experiments as followed;
Experiment 1; Investigated 4 methods of grinded fresh cassava root fermentation; thus, solely fermented fresh cassava root (T1), fermented fresh cassava root with urea (T2), fermented fresh cassava root with urea and yeast in closed system (T3), and fermented fresh cassava root with urea and yeast in opened system (T4). The experiment was arranged following Completely Randomized Design (CRD). Chemical compositions of treatments were evaluated. It found that methods of cassava root fermenting were not effect on ash (P>0.05). On the other hand, CP content was increased (P<0.01) when urea was mixed in fermentations. The NDF and ADF of T3 and T4 was decreased lower than of T2 (P<0.01). The in vitro gas production technique parameters were analyzed as following. Ammonia nitrogen (NH3-N) in fermented fluid of T1 was lower (P<0.05) than of T2, T3 and T4 at 3, 6, and 9 hour of incubation time. At 12 and 24 hour of incubation time, the NH3-N of T3 and T4 was higher than of T1 and T2 (P<0.05). The kinetics of gas production, it found that, rate of gas production (c) were not differ among treatments (P>0.05). Gas volume at 0 hour of incubation time (a) of T2 was lower than of T3 and T4 (P<0.05). Potential of gas production (d) and gas volume (b) of T1 was higher than the others (P<0.01).
Experiment 2; Four, non-pregnant female Brahman beef cattle (body weight 256 ± 11.5 kg) were randomly allocated to 4 treatments in 4 x 4 Latin square design with 21-d periods. Fresh cassava root was grinded and fermented for 21 days then fermented with yeast as yeast-fermented fresh cassava root. Cattle was fed rice straw as roughage. Dry matter intake was not difference among the treatments. However, ADG was trend to increase when yeast-fermented fresh cassava root was fed at 20 % in concentrate diet. Nutrients digestibilities were not differ among the treatments. However fiber digestibility (NDF and ADF) were trend to increase when yeast-fermented fresh cassava root was fed.
Yeast-fermented fresh cassava root was not effect on rumen ecology, however, there were trends of rumen bacteria population and microbial protein increasing in yeast-fermented fresh cassava root groups. It is concluded that yeast-fermented fresh cassava root could be used as protein source in cattle diet up to 30% with trend to enhance rumen bacteria population and NDF digestibility.