Effects of feeding different probiotic types on metabolic, performance, and carcass responses of Bos indicus feedlot cattle offered a high-concentrate diet

Abstract

Two experiments were designed to evaluate the effects of different probiotic combinations on rumen fermentation characteristics, performance, and carcass characteristics of feedlot Bos indicus beef bulls offered a high-concentrate diet. In Exp. 1, 30 rumen-fistulated Nellore steers were blocked by initial body weight (BW = 350 ± 35.0 kg) and within blocks (n = 10), animals were randomly assigned to receive: 1) high-concentrate diet without probiotic supplementation (n = 10; CONT), 2) CONT plus 1 g/head of a probiotic mixture containing three strains of E. faecium and one strain of S. cerevisiae (3.5 × 10 9 CFU/g; n = 10; EFSC), and 3) CONT plus 2 g/head of a probiotic mixture containing Bacillus licheniformis and B. subtilis (3.2 × 10 9 CFU/g; n = 10; BLBS). The experimental period lasted 35 d, being 28 d of adaptation and 7 d of sampling. From d 34 to 35 of the experimental period, ruminal fluid and fecal samples were collected every 3-h, starting immediately before feeding (0 h) for rumen fermentation characteristics and apparent nutrient digestibility analysis, respectively. In Exp. 2, 240 Nellore bulls were ranked by initial shrunk BW (372 ± 34.9 kg), assigned to pens (n = 4 bulls/pen), and pens randomly assigned to receive the same treatments as in Exp. 1 (n = 20 pens/treatment). Regardless of treatment, all bulls received the same step-up and finishing diets throughout the experimental period, which lasted 115 d. In both Exp., data were analyzed as orthogonal contrasts to partition specific treatment effects: 1) Probiotic effect: CONT vs. PROB, 2) Probiotic type: EFSC vs. BLBS (SAS Software Inc.). In Exp. 1, no contrast effects were observed on nutrient intake, overall nutrient digestibility, and rumen fermentation analyses (P ≥ 0.13). Nonetheless, supplementation of probiotics, regardless of type (P = 0.59), reduced mean acetate:propionate ratio and rumen ammonia-N concentration vs. CONT (P ≤ 0.05). In Exp. 2, no significant effects were observed for final BW and DMI (P ≥ 0.12), but ADG and FE tended to improve (P ≤ 0.10) when probiotics were offered to the animals. Probiotic supplementation or type of probiotic did not affect carcass traits (P ≥ 0.22). In summary, supplementation of probiotics containing a mixture of E. faecium and S. cerevisiae or a mixture of B. licheniformis and B. subtilis reduced rumen acetate:propionate ratio and rumen ammonia-N levels and tended to improve performance of feedlot cattle offered a high-concentrate diet.

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

“…Based on equations proposed and validated by others ( Valadares Filho et al, 2016 ), improvements in feedstuff NE g with DFM inoculation may result in an additional 32 g of carcass average daily gain ( cADG ) in a 450-kg body weight feedlot beef animal, leading to an approximate improvement of 60 g in ADG (considering a dressing percent = 53.0%). Supporting this calculation, Dias and colleagues (2022) recently observed a numerical improvement of 70 g/d in B. indicus feedlot bulls offered the same B. licheniformis and B. subtilis combination as the one evaluated herein.…”

“…The use of direct-fed microbials ( DFM ) has been gaining attention due to their benefits on the health and performance of the dairy and beef cattle herd ( FAO/WHO, 2001 ; Krehbiel et al, 2003 ; McAllister et al, 2011 ), besides also potentially replacing antibiotics and reducing public scrutiny against livestock production. More specifically, several types of DFM, or probiotics, have been evaluated under different production settings for young and mature ruminants, but increasing interest has been given to Bacillus spp., as its different modes of action warrant potential benefits as probiotics for humans and livestock species ( Dias et al, 2022 ; Luise et al, 2022 ).…”

Bacillus paralicheniformis 809 and Bacillus subtilis 810 support in vitro intestinal integrity under hydrogen peroxide and deoxynivalenol challenges

“…Nonetheless, additional studies are warranted to understand if the combination of both strains will yield similar or better results than the current ones evaluating the single DFM strains. In fact, despite a lack of studies evaluating the intestinal integrity of both strains under an in vivo ruminant setting, feeding a combination of B. licheniformis 809 and B. subtilis 810 has resulted in greater nutrient digestibility ( Pan et al., 2022 ; Cappellozza et al., 2023b ; Oyebade et al., 2023 ), heavier calves at weaning ( Kowalski et al., 2009 ), greater milk solids yield, milk yield, and efficiency ( Kritas et al., 2006 ; Cappellozza et al., 2024 ; Oyebade et al., 2023 ), and greater feed efficiency in feedlot beef cattle ( Dias et al., 2022 ). Moreover, while our in vitro findings suggest beneficial impacts of these two probiotic strains intestinal mucosal oxidative stress, it will be interesting to investigate whether they may also impact systemic oxidative stress as suggested for other strains of Bacilli ( Crescenzo et al., 2017 ; Zhang et al., 2021 ).…”

Evaluation of direct-fed microbials on in vitro ruminal fermentation, gas production kinetic, and greenhouse gas emissions in different ruminants’ diet

“…Due to their direct effects on microbial communities and cellular function, DFM were primarily studied regarding their impact on immune modulation in the gastrointestinal tract (Krehbiel et al, 2003;Ballou et al, 2019). However, positive effects of DFM on rumen fermentation have also been reported in the literature (Nocek et al, 2003;Qiao et al, 2010;Lettat et al, 2012;Mamuad et al, 2019;Dias et al, 2022;Wang et al, 2022).…”