Berto, Patrícia N.Tse, Marcos L.P.Ramos, Denis R.A.Saleh, Mayra A.D.Miassi, Gabriela M.Yamatogi, Ricardo S.Berto, Dirlei A.Neto, Messias A.T.2020-12-102020-12-102020Berto, P.N., Tse, M.L.P., Ramos, D.R.A., Saleh, M.A.D., Miassi, G.M., Yamatogi, R.S., Berto, D.A., Neto, M.A.T. (2020). Dietary supplementation with hydrolyzed yeast and its effect on the performance, intestinal microbiota, and immune response of weaned piglets. Anais da Academia Brasileira de Ciências, 92(suppl.1): e201809690001-3765http://hdl.handle.net/10400.14/31449The objective of this study was to evaluate the effects of autolyzed yeast on performance, cecal microbiota, and leukogram of weaned piglets. A total of 96 piglets of commercial line weaned at 21-day-old were used. The experimental design was a randomized block design with four treatments (diets containing 0.0%, 0.3%, 0.6%, and 0.9% autolyzed yeast), eight replicates, and three animals per pen in order to evaluate daily weight gain, daily feed intake, and feed conversion in periods of 0 to 15, 0 to 26, and 0 to 36 days. Quadratic effects of autolyzed yeast inclusion were observed on the feed conversion from 0 to 15 days, on daily weight gain from 0 to 15 days, 0 to 26 days and, 0 to 36 days, indicating an autolyzed yeast optimal inclusion level between 0.4% and 0.5%. No effect from autolyzed yeast addition was observed on piglet daily feed intake, cecal microbiota, and leukogram; however, i.m. application of E. coli lipopolysaccharide reduced the values of total leukocytes and their fractions (neutrophils, eosinophils, lymphocytes, monocytes, and rods). Therefore, autolyzed yeast when provided at levels between 0.4% and 0.5% improved weaned piglets’ performance.engImmune systemLeukogramNutritionSwineWeaningjournal article10.1590/0001-37652020201809691678-26908508917072532756838000558766900001