Development of highly digestible animal feed from lignocellulosic biomass Part 1: Oxidative lime pretreatment (OLP) and ball milling of forage sorghum1

Abstract

To feed a growing population, alternative sources of animal feed (e.g., lignocellulose) are needed to replace grains (e.g., corn). Oxidative lime pretreatment (OLP) increases lignocellulose digestibility by removing lignin and hemicellulose acetyl content. Adding a mechanical pretreatment (e.g., ball milling) further improves digestibility. This study determines the effectiveness of OLP and ball milling to enhance the ruminant digestibility of lignocellulose. For forage sorghum, the 48-h in vitro TDN were 40, 64, and 84 g nutrients digested/100 g organic matter (OM) for raw, short-term OLP, and short-term OLP + ball milling, respectively. In terms of compositional changes, OLP increases NDF and decreases non-fiber carbohydrate (NFC) and crude protein (CP), all of which would normally be associated with a decrease in digestibility. However, because OLP and ball milling beneficially change composition (lignin removal) and structural features (reduced crystallinity), digestibility actually increases. Although ball milling increases digestibility according to standard laboratory assays, it reduces particle size possibly allowing fine particles to escape from the rumen before they are digested, thus limiting its practical application. Nonetheless, this study indicates that mechanical pretreatment greatly increases digestibility, and therefore it is desirable to identify an effective mechanical treatment that retains fiber integrity.

Development of highly digestible animal feed from lignocellulosic biomass Part 2: Oxidative lime pretreatment (OLP) and shock treatment of corn stover1

“…The supernatant was concentrated using rotary evaporation, and then freeze-dried to a powder using a Labconco Lyph-Lock 6-L freeze dryer system (Model 77530, Labconco Corporation, Kansas City, MO). Cumberland Valley Analytical Services, Inc. (Hagerstown, MD) performed the compositional analysis for corn stover samples ( Table 1 ); the analytical methods are reported by Falls et al (2017) . Two materials were used as controls: cracked corn grain and alfalfa.…”

“… Falls et al (2017) describes a combination of oxidative lime pretreatment (OLP) and ball milling to generate highly digestible forage sorghum to supplement or replace corn grain as ruminant animal feed. Even though rumen digestibilities of this pretreated forage sorghum are high based on laboratory assays, ball-milled material has no practical use as feed because it is extremely expensive.…”

“…Even though the study reported by Falls et al (2017) did not result in a practical treatment, the following valuable lessons were obtained: (1) use feedstock with low protein content, which prevents its loss in OLP; (2) extensively wash the biomass to remove ash from OLP; and (3) select a mechanical pretreatment that maintains fiber integrity so it is retained in the rumen until digested.…”

Enhancement the feeding value of rice straw as animal fodder through microbial inoculants and physical treatments

“…These findings are in agreement with Mahrous and Abou Ammou (2005). The presence of high concentrations from ADF and NDF in rice straw is responsible for its poor nutritive value and lower digestibility as animal feed, since high concentrations from NDF and ADF could be responsible for low digestibility in animals (Falls et al 2017;Sath et al 2012). Reducing the concentration of ADF and NDF in rice straw converted it into more nutritive and easily digestible animal feed (Sharma and Arora 2011).…”

Quantitative visualization of subcellular lignocellulose revealing the mechanism of alkali pretreatment to promote methane production of rice straw

“…This results in inefficient conversion of biomass [1,4,5]. To make lignocellulosic biomass less refractory, chemical pretreatments (the application of strong acids or bases), physical pretreatments such as ball milling [6], and other methods such as thermal and biological (application of microorganisms to decompose lignin and lignocellulose) pretreatments have been extensively studied and applied in recent years. Some pretreatment methods showed a significant improvement of gas yield and production rate [4,[7][8][9][10][11].…”