Effects of a Bacillus-based direct-fed microbial on in vitro nutrient digestibility of forage and high-starch concentrate substrates

Abstract

Two experiments evaluated the effects of a Bacillus-based direct-fed microbial on in vitro dry matter (DM) and neutral detergent fiber (NDF; Exp. 1), and starch (Exp. 2) digestibility of a variety of ruminant feedstuffs. In Exp. 1, ten forage sources were evaluated: ryegrass, alfalfa hay, leucaena, corn silage, spinifex, buffel grass, flinders grass, Mitchell grass, rhodes grass hay, and Queensland bluegrass. Experimental treatments were a Control, forages with no probiotic inoculation; CON) or forages sources inoculated with a mixture containing Bacillus licheniformis and B. subtilis (3.2 × 10 9 CFU/g; DFM). In vitro DM and NDF digestibility were evaluated at 24- and 48-hours post-treatment inoculation. Treatment × hour interactions were noted for IVDMD and IVNDFD (P ≤ 0.05). More specifically, DFM inoculation increased (P ≤ 0.03) IVDMD at 24 hours in four forages and increased 48-hour IVDMD (P ≤ 0.02) in alfalfa hay, ryegrass, leucaena, and Mitchell grass hay, but opposite results were observed for Queensland bluegrass (P < 0.01). Twenty-four and 48-hour IVNDFD increased following DFM inoculation (P ≤ 0.02) in five forage sources, but reduced for Queensland bluegrass (P < 0.01). When the forages were classified according to their quality, main treatment effects were detected for IVDMD (P ≤ 0.02) and IVNDFD (P < 0.01). In Exp. 2, five common cereal grains were evaluated [high-density barley (82 g/100 mL), low-density barley (69 g/100 mL), corn, sorghum, and wheat] under the same treatments as in Exp. 1. In vitro starch digestibility was evaluated at 6- and 12-hours following treatment inoculation. Treatment × hour interactions were observed for starch digestibility in 3 out of 5 concentrate sources (P ≤ 0.001). Inoculation of DFM yielded greater 24-hour starch digestibility for high-, low-density barley, and wheat (P ≤ 0.02), but also greater at 48 hours in wheat (P < 0.0001). Moreover, mean starch digestibility improved for corn and sorghum inoculated with DFM (P < 0.01). Using a Bacillus-based DFM (B. licheniformis and B. subtilis) improved mean in vitro DM and NDF digestibility of different forage sources of varying qualities (based on CP content). Similarly, in vitro starch digestibility was also greater following DFM inoculation, highlighting the potential of this probiotic to improve nutrient digestibility and utilization into the beef and dairy cattle herd.

Evaluation of a Bacillus-based direct-fed microbial probiotic on in vitro rumen gas production and nutrient digestibility of different feedstuffs and total mixed rations

“…Following experiment 1., data from this and our previous in vitro research study ( Pan et al, 2022 ) were compiled into a larger dataset ( N = 16 forage-based feedstuffs) to understand how Bacillus -based DFM would impact in vitro nutrient digestibility (IVDMD and IVNDFD). Of note, Pan et al (2022) evaluated 10 different single forage-based feedstuffs inoculated or not with the same Bacillus -based DFM (BOVACILLUS; Chr. Hansen A/S) evaluated herein.…”

“…have been recognized ( www.lpsn.dsmz.de ). Recently, Pan et al (2022) reported that a mixture of B. licheniformis and B. subtilis improved in vitro dry matter ( DM ), neutral detergent fiber ( NDF ), and starch digestibility of forage-based and concentrate feedstuffs originated from Australia, indicating that the ability of Bacillus spp. to produce and release a wide type and quantity of enzymes might promote feedstuff or nutrient utilization ( Schallmey et al, 2004 ; Elshaghabee et al, 2017 ; Luise et al, 2022 ) in ruminants.…”

“…Therefore, our objective was to evaluate the effects of Bacillus spp. incubation on in vitro gas production and nutrient digestibility of individual feedstuffs (experiment 1) and commercial dairy TMR (experiment 2), as well as to perform a combined analysis with feedstuffs previously used by Pan et al (2022; experiment 3).…”

The importance of cellulolytic and xylanolytic activities ofBacillus subtilison dairy cow feed digestibility

“…The effects of Bacillus spp. on in vitro digestibility of forages included in ruminant diets and its ability to increase in NDFd is not novel (Sun et al, 2013; Romero et al, 2015; Jia et al, 2022; Pan et al, 2022). The novelty of our work was the demonstration that the cellulases and xylanases secreted by this microorganism are effectively involved in the recovery of nutrients from fibrous material.…”

New probiotics (Lactobacillus plantarum and Saccharomyces cerevisiae) supplemented to fermented rice straw-based rations on digestibility and rumen characteristics in vitro

“…The biological treatment of rice straw resulted in a decrease in ADF concentration and NDF, so it is more easily digested by livestock and has a higher nutritional value. As described in the study of Pan et al [ 30 ], who reported that various forages were inoculated with microbial mixtures containing Bacillus licheniformis and B. subtilis (3.2 × 10 9 CFU/gm DFM), increasing the average digestibility of the DM and NDF with various quality levels of protein and NDF. The increased digestibility of the fiber fraction is due to the cellulase enzymes secreted by microbial inoculants.…”