149841 20251017144552.0 doi 10.1016/j.anifeedsci.2019.114273 sideral 113520 ART-2019-113520 eng Yuste, S. Universidad de Zaragoza (orcid)0000-0003-3927-9793 Rumen protozoal dynamics during the transition from milk/grass to high-concentrate based diet in beef calves as affected by the addition of tannins or medium-chain fatty acids 2019 Access copy available to the general public Unrestricted Changes in rumen protozoal community during adaptation of 7-month-old beef calves from a milk/grass diet to a high-energy diet consisting of cereal-based concentrate plus wheat straw, both given ad libitum (diet C), were studied. Eighteen rumen-cannulated Limousine crossbred male calves were randomly assigned to three diets (C; C plus 20 g/kg of a 65:35 chestnut and quebracho tannin extract, T; and C plus 6 g/kg medium-chain fatty acid (MCFA) mixture, M). Fermentation variables were studied, and rumen ciliates were quantified and classified from rumen fluid sampled just before the morning feeding on days 0, 7, 14, 21 and 28 of the experiment. Protozoal population changed over time, but all calves harbored a stable population at the end of the experiment. Diversity decreased on time, and Entodinium and Isotricha species were the most abundant at the end of the trial. When occurred, defaunation was transient as protozoa were absent from M calves in three occasions on days 7 and 14 but were refaunated thereafter reaching a consistent population. Regardless the diet, proportions of Isotricha spp. and Dasytricha ruminantium, Epidinium spp. and Subfamily Diplodiniinae, decreased throughout the experiment, whereas Entodinium spp. increased reaching 0.93 of total protozoa. Dasytricha and protozoa from Subfamily Diplodiniinae disappeared from the rumen of all calves at the end of the study, except for Polyplastron multivesiculatum. Rumen variables were not affected by the addition of additives (P > 0.05). Rumen pH decreased across the study (P < 0.001) but did not reach acidotic values despite the high fermentability of the diet. Higher levels of lactate were observed on C calves at d14, but not in other dates (diet by day interaction, P = 0.03). Addition of tannin extract did not affect protozoal concentration and diversity, but MCFA might even lead to a transient defaunation. Transition to a high-concentrate diet does not necessarily reduce initial protozoal concentration, but diversity is affected towards a major proportion of Entodinium and, to a lesser extent, Isotricha. Dietary shift from weaning to a high-concentrate ration promotes a less diverse rumen protozoal population, but a high concentration is still maintained thereafter. info:eu-repo/grantAgreement/ES/MICINN/AGL2013-46820 info:eu-repo/semantics/openAccess All rights reserved http://www.europeana.eu/rights/rr-f/ 2.582 2019 AGRICULTURE, DAIRY & ANIMAL SCIENCE 8 / 63 = 0.127 2019 Q1 T1 1.121 2019 Animal Science and Zoology 2019 Q1 info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion Amanzougarene, Z. Universidad de Zaragoza (orcid)0000-0001-8932-4615 Fuente, G. de la Vega, A. de Universidad de Zaragoza (orcid)0000-0002-8753-8887 Fondevila, M. Universidad de Zaragoza (orcid)0000-0002-0712-1185 2008 700 Universidad de Zaragoza Dpto. Produc.Animal Cienc.Ali. Área Producción Animal 257 (2019), 114273 [10 pp.] Anim. feed sci. technol. Animal Feed Science and Technology 0377-8401 417706 http://zaguan.unizar.es/record/149841/files/texto_completo.pdf Postprint 575051 http://zaguan.unizar.es/record/149841/files/texto_completo.jpg?subformat=icon icon Postprint oai:zaguan.unizar.es:149841 articulos driver 2025-10-17-14:12:05 ARTICLE