Effects of graded levels of liquid brewer's yeast on chemical composition and fermentation quality in cassava pulp and rice straw‐based total mixed ration silage

Abstract

This study aimed to evaluate the effect of liquid brewer's yeast (LBY) addition on chemical composition and fermentation quality of mixture of LBY and cassava pulp (CVP) with rice straw (RS) in different ratios during preservation periods. Four mixtures of LBY, CVP and RS were made, that is mixture ratio of LBY : CVP : RS of 0% LBY, 20% LBY, 35% LBY and 50% LBY were 0:70:30, 20:50:30, 35:35:30 and 50:20:30 as fresh matter, respectively. The bags were opened at weeks 0, 1, 2, 4 and 8 after storage. The contents of dry matter, organic matter, crude protein (CP), ether extract (EE), neutral detergent fiber and acid detergent fiber ranged 36.4-40.0, 88.9-90.8, 4.0-12.0, 1.1-1.3, 58.8-61.6 and 37.6-40.0, respectively, and the contents of CP and EE increased and the other components decreased in proportion to LBY inclusion (P < 0.01). 50% LBY had the highest (P < 0.05) pH (4.81) and ammonia nitrogen per total nitrogen (NH -N/TN) (7.40%) and the lowest V-score (90.3). Propionic and butyric acid contents were 0.01% or lower in each mixture and storage period. There were rapid pH decrease and NH -N/TN increase during the first week of the storage period. The increases of NH -N/TN and acetic acid content and decreases of pH, lactic acid content and V-score during the preservation were more drastic as LBY inclusion increased. Although higher proportion of LBY produced higher CP and lower fiber contents in the mixture, attention should be paid for the reduction of fermentation quality during longer storage periods.

Sweet Corn Stalk Treated with Saccharomyces Cerevisiae Alone or in Combination with Lactobacillus Plantarum: Nutritional Composition, Fermentation Traits and Aerobic Stability

“…The reduced aerobic stability of the silage inoculated with S. cerevisiae alone was mainly due to the high pH value (4.3–4.4) that could not inhibit the growth of aerobic spoilage bacteria after opening. This result is consistent with the outcome of a high pH and poor stability observed by Kamphayae et al [23] when a high proportion of liquid brewer’s yeast was included. In contrast, a lower inoculation dose (10 3 –10 5 cfu/g) of S. cerevisiae did not affect the pH and aerobic stability of corn silage [18,19].…”

“…This inconsistency is possibly due to the difference in application dose of S. cerevisiae . Additional supportive evidence is provided by Kamphayae et al [23], who observed an increase in pH when the proportion of liquid brewer’s yeast included in the mixed silage of cassava pulp and rice straw increased. Thus, for a high inoculation dose of S. cerevisiae , a method by which the ammonia production can be reduced in silage must first be identified.…”

“…Hence, the high application size of S. cerevisiae (32.5 g/kg DM) was estimated to provide silage with an additional 13 to 19 g/kg DM of microbial protein, which almost explained the increase in CP in the inoculated silages. Similarly, Kamphayae et al [23] reported that the CP content of the fermented end-product increased in proportion to the inclusion of increased brewer’s yeast during the short ensiling of a total mixed ration containing cassava pulp. However, it is not clear whether the increase in the CP concentration was accompanied by the proliferation of the S. cerevisiae population and the increase in true microbial protein.…”

“…S. cerevisiae can secrete nitrogen-metabolic enzymes to effectively degrade exogenous amino acids and peptides into inorganic nitrogen, and inorganic ammonia plays a central role as an intermediate between degradative and biosynthetic pathways in nitrogen metabolism in S. cerevisiae [22]. Although the NH 3 –N and pH were not altered at the dose of 10 3 to 10 5 cfu/g of fresh forage [18,19], a short-term fermentation study showed that the inclusion of liquid brewer’s yeast at a high proportion raised the pH and ammonia nitrogen (NH 3 –N) in rice straw silage [23]. The concern that a high-dose inoculation with S. cerevisiae may increase plant protein degradation and impair nutritional quality of silage was raised.…”

Chemical composition and nutritive values of cassava pulp for cattle

“…Cassava ( Manihot esculenta Crantz) pulp is a by‐product of starch manufacturing, and its disposal can cause environmental problems (Napasirth et al., ; Sriroth, et al., ). However, it can be used as a major biomass resource for animal feeding (Kamphayae et al., ). In 2016, 31.16 million tonnes of cassava were produced in Thailand.…”