Improving the nutritive value of cassava bioethanol waste using fermented yeast as a partial replacement of protein source in dairy calf ration

Abstract

The aim of this work was to evaluate the influence of yeast (Saccharomyces cerevisiae)–fermented cassava bioethanol waste (YECAW) on feed utilization, ruminal fermentation, and microbial population in dairy calves fed a concentrate diet at 1% body weight (BW). Four male Holstein Friesian crossbred calves with an initial BW of 109 ± 6.23 kg were used in this research. The experimental design was a 4 × 4 Latin squared design and the dietary treatments were four levels of YECAW supplementation at 0%, 5%, 10%, and 20% concentrate mixture. The YECAW product contained CP at 25.1% dry matter (DM) and NDF and ADF at 65.2 and 40.6% DM, respectively. Inclusion of YECAW did not alter feed intake of rice straw, total intake, nutrient intake, and digestion coefficients (P > 0.05). Ruminal pH and temperature, ruminal ammonia-nitrogen, and blood urea-nitrogen (BUN) were not significant by YECAW levels supplementation (P > 0.05). Increasing YECAW levels did not adversely affect the population of bacteria, protozoa, and fungi and values ranged from 6.5 to 7.0 × 10¹², 3.2 to 4.0 × 10⁵, and 6.9 to 7.4 × 10³ cells/ml, respectively (P > 0.05). Feeding of YECAW to dairy calves did not affect the total VFA, acetic acid (C2), propionic acid (C3), or butyric acid (C4) proportion (P > 0.05) which ranged from 102.6 to104.6 mmol/l, 70.7 to 72.0, 17.8 to 20.2, and 9.1 to 10.3 mol/ 100 mol, respectively. Therefore, feeding of YECAW is recommended because no adversely affect the utilization of feed and rumen characteristics and might be alternative protein source for ruminants.