Manipulation of In Vitro Ruminal Fermentation and Feed Digestibility as Influenced by Yeast Waste-Treated Cassava Pulp Substitute Soybean Meal and Different Roughage to Concentrate Ratio

Abstract

Cassava pulp (CS) is high in fiber and low in protein; hence, improving the nutritive value of CS is required to increase its contribution to enhancing ruminant production. The present work hypothesized that CS quality could be enhanced by fermentation with yeast waste (YW), which can be used to replace soybean meal (SBM), as well as lead to improved feed utilization in ruminants. Thus, evaluation of in vitro ruminal fermentation and feed digestibility, as influenced by YW-treated CS and different roughage (R) to concentrate (C) ratios, was elucidated. The design of the experiment was a 5 × 3 factorial arrangement in a completely randomized design. Each treatment contained three replications and three runs. The first factor was replacing SBM with CS fermented with YW (CSYW) in a concentrate ratio at 100:0, 75:25, 50:50, 25:75, and 0:100, respectively. The second factor was R:C ratios at 70:30, 50:50, and 30:70. The level of CSYW showed significantly higher (p < 0.01) gas production from the insoluble fraction (b), potential extent of gas production (a + b), and cumulative gas production at 96 h than the control group (p < 0.05). There were no interactions among the CSYW and R:C ratio on the in vitro digestibility (p > 0.05). Furthermore, increasing the amount of CSYW to replace SBM up to 75% had no negative effect on in vitro neutral detergent fiber degradability (IVNDFD) (p > 0.05) while replacing CSWY at 100% could reduce IVNDFD (p > 0.05). The bacterial population in the rumen was reduced by 25.05% when CSYW completely replaced SBM (p < 0.05); however, 75% of CSWY in the diet did not change the bacterial population (p > 0.05). The concentration of propionate (C3) decreased upon an increase in the CSYW level, which was lowest with the replacement of SBM by CSYW up to 75%. However, various R:C ratios did not influence total volatile fatty acids (VFAs), and the proportion of VFAs (p > 0.05), except the concentration of C3, increased when the proportion of a concentrate diet increased (p < 0.05). In conclusion, CSYW could be utilized as a partial replacement for SBM in concentrate diets up to 75% without affecting gas kinetics, ruminal parameters, or in vitro digestibility.

Feed utilization efficiency and ruminal metabolites in beef cattle fed with cassava pulp fermented yeast waste replacement soybean meal

“…The pH and temperature remain constant at 38.8 and 39.0 °C, respectively. Moreover, Dagaew et al 5 found that CSYW replacement SBM in concentrate at 100% did not affect ruminal pH or ruminal temperature.…”

“…By chemically dissolving structural fibers' ester linkages, concentrated alkaline substances can physically inflate them. In a prior in vitro investigation 5 , discovered that when SBM was replaced with 100% CSYW, in vitro dry matter digestibility did not change. Similarly, Cherdthong and Supapong 11 showed that feeding dairy calves a concentrate diet containing 20.0% cassava bioethanol waste fermented by S. cerevisiae had no negative impact on feed intake or nutrient digestion.…”

“…This could be the principal consequence of the medium solution containing 50 g of urea, which resulted in a higher N content in the product. Furthermore, throughout the fermentation process, yeast containing YW may proliferate in the form of single-cell proteins, which could explain the apparent increase in CP 5 .…”

“…Cassava pulp is a year-round available industrial by-product of cassava starch production 4 . Cassava pulp has a CP value of 2.0–3.0% DM and a small amount of residual starch 5 , indicating that it could be utilized in ruminant animal diets. Conversely, the high fiber content of cassava pulp restricted the amount of feed consumed and the rate of digestion in cattle.…”

“…As a consequence, using yeast waste to improve cassava pulp quality could be intriguing, especially in terms of lowering feed costs and reducing factory waste. Dagaew et al 5 have revealed that employing yeast waste fermented cassava pulp can enhance the CP of feed products from 23.0 to 53.7% DM and can replace SBM up to 75.0% in concentrate diets without impairing gas production or in vitro digestibility. However, an in vivo experiment is required to evaluate the cassava pulp fermented yeast waste (CSYW) product.…”