000149841 001__ 149841 000149841 005__ 20251017144552.0 000149841 0247_ $$2doi$$a10.1016/j.anifeedsci.2019.114273 000149841 0248_ $$2sideral$$a113520 000149841 037__ $$aART-2019-113520 000149841 041__ $$aeng 000149841 100__ $$0(orcid)0000-0003-3927-9793$$aYuste, S.$$uUniversidad de Zaragoza 000149841 245__ $$aRumen 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 000149841 260__ $$c2019 000149841 5060_ $$aAccess copy available to the general public$$fUnrestricted 000149841 5203_ $$aChanges 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. 000149841 536__ $$9info:eu-repo/grantAgreement/ES/MICINN/AGL2013-46820 000149841 540__ $$9info:eu-repo/semantics/openAccess$$aAll rights reserved$$uhttp://www.europeana.eu/rights/rr-f/ 000149841 590__ $$a2.582$$b2019 000149841 591__ $$aAGRICULTURE, DAIRY & ANIMAL SCIENCE$$b8 / 63 = 0.127$$c2019$$dQ1$$eT1 000149841 592__ $$a1.121$$b2019 000149841 593__ $$aAnimal Science and Zoology$$c2019$$dQ1 000149841 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/acceptedVersion 000149841 700__ $$0(orcid)0000-0001-8932-4615$$aAmanzougarene, Z.$$uUniversidad de Zaragoza 000149841 700__ $$aFuente, G. de la 000149841 700__ $$0(orcid)0000-0002-8753-8887$$aVega, A. de$$uUniversidad de Zaragoza 000149841 700__ $$0(orcid)0000-0002-0712-1185$$aFondevila, M.$$uUniversidad de Zaragoza 000149841 7102_ $$12008$$2700$$aUniversidad de Zaragoza$$bDpto. Produc.Animal Cienc.Ali.$$cÁrea Producción Animal 000149841 773__ $$g257 (2019), 114273 [10 pp.]$$pAnim. feed sci. technol.$$tAnimal Feed Science and Technology$$x0377-8401 000149841 8564_ $$s417706$$uhttps://zaguan.unizar.es/record/149841/files/texto_completo.pdf$$yPostprint 000149841 8564_ $$s575051$$uhttps://zaguan.unizar.es/record/149841/files/texto_completo.jpg?subformat=icon$$xicon$$yPostprint 000149841 909CO $$ooai:zaguan.unizar.es:149841$$particulos$$pdriver 000149841 951__ $$a2025-10-17-14:12:05 000149841 980__ $$aARTICLE