title: Evaluation of isoquinoline alkaloid supplementation levels on ruminal fermentation, characteristics of digestion, and microbial protein synthesis in steers fed a high-energy diet.
abstract: Four Holstein steers with ruminal and duodenal cannulas were used in a 4 × 4 Latin square design to examine the effect of daily intake of 0, 2, 4 or 6 g/steer of standardized plant extract containing a mixture of quaternary benzophenanthridine alkaloids and protopine alkaloids (QBA+PA) on the characteristics of ruminal fermentation and characteristics of digestion. The basal diet consisted of a steam-flaked corn-based finishing diet that contained 62% corn and 12% sudangrass hay and the rest of diet was composed of mainly dried distillers grains, molasses, fat, and minerals. The source of QBA+PA used was Sangrovit-RS (Phytobiotics Futterzusatzstoffe GmbH, Eltville, Germany) and supplementation levels of 2, 4, and 6 g Sangrovit-RS∙steer∙d, which represented a net daily ingestion of approximately 6, 12, and 18 mg of QBA+PA compounds, respectively. Inclusion of QBA+PA linearly increased ( = 0.04) flow to the duodenum of nonammonia N and linearly decreased ( < 0.01) duodenal flows of ammonia N. Ruminal microbial efficiency (duodenal microbial N; g/kg OM fermented in the rumen) and protein efficiency (duodenal nonammonia N; g/g N intake) were increased ( < 0.05) as the level of QBA+PA increased. There were no effects of QBA+PA supplementation on ruminal, postruminal, and total tract digestion of OM, starch, and NDF, but postruminal and total tract digestion of N increased ( < 0.01) as the level of QBA+PA increased. Digestible energy of the diet tended to increase (linear affect, = 0.09) with QBA+PA supplementation. Ruminal pH and total VFA molar concentrations were not different between treatments. Ruminal NH-N concentration linearly decreased ( = 0.02) with QBA+PA supplementation. Ruminal molar proportion of acetate increased ( = 0.04) as the supplementation level of QBA+PA increased. It is concluded that QBA+PA supplementation enhances efficiency of N utilization in feedlot steers fed a steam-flaked corn-based finishing diet. This effect was due, in part, to enhanced ruminal microbial efficiency, decreased ruminal degradation of dietary nonammonia N, and enhanced postruminal N digestion.
authors.forename: J A
authors.initials: JA
authors.lastname: Aguilar-Hernández
authors.forename: J D
authors.initials: JD
authors.lastname: Urías-Estrada
authors.forename: M A
authors.initials: MA
authors.lastname: López-Soto
authors.forename: A
authors.initials: A
authors.lastname: Barreras
authors.forename: A
authors.initials: A
authors.lastname: Plascencia
authors.forename: M
authors.initials: M
authors.lastname: Montaño
authors.forename: V M
authors.initials: VM
authors.lastname: González-Vizcarra
authors.forename: A
authors.initials: A
authors.lastname: Estrada-Angulo
authors.forename: B I
authors.initials: BI
authors.lastname: Castro-Pérez
authors.forename: R
authors.initials: R
authors.lastname: Barajas
authors.forename: H I
authors.initials: HI
authors.lastname: Rogge
authors.forename: R A
authors.initials: RA
authors.lastname: Zinn
mesh_terms: D000470:Alkaloids / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D000641:Ammonia / Q000378:metabolism; D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D001419:Bacteria / Q000378:metabolism; D002417:Cattle / Q000502:physiology*; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements; D004063:Digestion / Q000187:drug effects*; D005285:Fermentation; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D007546:Isoquinolines / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D012417:Rumen / Q000187:drug effects* / Q000378:metabolism; D003313:Zea mays / Q000737:chemistry
chemical_list: D000470:Alkaloids; D007546:Isoquinolines; D000641:Ammonia