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The rumen simulation technique (RUSITEC) was used to investigate the effect of ergot alkaloids (EA) and a mycotoxin deactivating product (Biomin AA; MDP) on nutrient digestion, ruminal fermentation parameters, total gas, methane, and microbial nitrogen production. Ruminal fermentation vessels received a feedlot finishing diet of 90:10 concentrate:barley silage (DM basis). Using a randomized complete block design, treatments were assigned (n = 4 vessels/treatment) within two RUSITEC apparatuses in a 2 × 2 factorial arrangement. Treatments included: (1) control (CON) diet (no EA and no MDP); (2) CON diet + 1 g/d MDP; (3) CON diet + 20 mg/kg EA; and (4) CON diet + 20 mg/kg EA + 1 g/d MDP. The study was conducted over 14 d with 7 d of adaptation and 7 d of sample collection. Data were analyzed in SAS using PROC MIXED including fixed effects of EA, MDP, and the EA×MDP interaction. Random effects included RUSITEC apparatus and cow rumen inoculum (n = 4). Ergot alkaloids decreased dry matter (DMD) (P = 0.01; 87.9 vs. 87.2%) and organic matter disappearance (OMD) (P = 0.02; 88.8 vs. 88.4%). Inclusion of MDP increased OMD (P = 0.01; 88.3 vs. 88.9%). Neutral detergent fiber disappearance (NDFD) was improved with MDP; however, an EA×MDP interaction was observed with MDP increasing (P < 0.001) NDFD more with EA diet compared to CON. Acetate proportion decreased (P = 0.01) and isovalerate increased (P = 0.03) with EA. Consequently, acetate:propionate was reduced (P = 0.03) with EA. Inclusion of MDP increased total volatile fatty acid (VFA) production (P < 0.001), and proportions of acetate (P = 0.03) and propionate (P = 0.03), and decreased valerate (P < 0.001), isovalerate (P = 0.04), and caproate (P = 0.002). Treatments did not affect (P ≥ 0.17) ammonia, total gas, or methane production (mg/d or mg/g of organic matter fermented). The inclusion of MDP reduced (P < 0.001) microbial nitrogen (MN) production in the effluent and increased (P = 0.01) feed particle-bound MN. Consequently, total MN decreased (P = 0.001) with MDP. In all treatments, the dominant microbial phyla were Firmicutes, Bacteroidota, and Proteobacteria, and the major microbial genus was Prevotella. Inclusion of MDP further increased the abundance of Bacteroidota (P = 0.04) as it increased both Prevotella (P = 0.04) and Prevotellaceae_UCG-003 (P = 0.001). In conclusion, EA reduced OMD and acetate production due to impaired rumen function, these responses were successfully reversed by the addition of MDP. [ABSTRACT FROM AUTHOR]

A rumen simulation technique (RUSITEC) investigated effects of ergot alkaloids (E) and a mycotoxin deactivating product (Biomin® AA; B) on nutrient digestion, rumen fermentation, total gas and methane emissions. Fermenters received a finishing diet of 90:10 concentrate:barley silage. Using a randomized complete block design, treatments were assigned (4 vessels/treatment) within two RUSITECs in a 2 × 2 factorial. Treatments included: 1) control diet, 2) control + 1 g B, 3) control + 20 ppm E, and 4) control + 20 ppm E + 1 g B. The study had a 14-d experimental period, with 7-d adaptation and 7-d sample collection. Data were analyzed in SAS using PROC mixed including fixed effects of E, B, and E×B interaction. Random effects included RUSITEC apparatus and cow rumen inoculum (n = 4). Ergot decreased dry matter disappearance (DMD) (P < 0.05; 87.9 vs. 87.2%) and organic matter disappearance (OMD) (P < 0.05; 88.8 vs. 88.4%). Adding B increased OMD (P < 0.05; 88.3 vs. 88.9%) and neutral detergent fiber disappearance (NDFD) (P < 0.01); however, an E×B interaction was observed for NDFD (P < 0.01) with B promoting greater increases with E. Ergot decreased acetate proportions (P < 0.01) and increased isovalerate (P < 0.05). Consequently, acetate:propionate was reduced (P < 0.05) with E. Inclusion of B increased total volatile fatty acids (P < 0.01), and proportions of acetate (P < 0.05) and propionate (P < 0.05), and decreased valerate (P < 0.01), isovalerate (P < 0.01), and caproate (P < 0.01). Treatments did not affect (P = 0.17) ammonia-N, total gas, or methane production (mg/d or mg/g of OM fermented). In conclusion, E reduced OMD and acetate production, but these responses were reversed by the addition of B. [ABSTRACT FROM AUTHOR]