Use of Saccharomyces cerevisiae-based products and effects on rumen environment and performance of sheep subjected to dietary changes

Natural additives in ruminant diet optimizes animal performance by controlling or modifying the rumen fermentation pattern. The aim of this study was to evaluate the effects of using Saccharomyces cerevisiae products during abrupt changes in dietary starch concentration on ruminal pH maintenance, performance and metabolism of confined sheep. Twenty adult ewes, crossbred Texel x Corriedale(44.7±6.97 Kg BW) were divided into three groups: Control (n=6), Cultron X (yeast culture; n=7) and Cultron Pro (hydrolyzed yeast; n=7), administered at a dose of 5 g/sheep/day (10x1010CFU/g DM). The experiment lasted 20 days divided into four periods, alternating between 40 and 60% concentrate. Blood and ruminal fluid were collected at the end of each period, and daily dry matter intake was measured to determine the average daily gain (ADG). Blood tests included blood count and biochemical parameters such as glucose, urea, total plasma proteins (TPP), liver enzymes, acute phase proteins and minerals. There was an upward trend in ADG in group Cultron X compared to control in period 3. Although, ruminal pH did not differ between groups, protozoan motility was higher in animals supplemented with hydrolyzed yeast. The Cultron Pro group showed an increase in TPP in periods 3 and 4, and AST in periods 2 and 3 compared to the control group. There was no difference in other metabolites. Yeast supplementation is a potential tool in times of feeding challenge, in which yeast culture is the most effective for improving performance of confined sheep being in improving performance of confined sheep. RESUMO: A utilização de aditivos naturais na dieta de ruminantes é uma prática que otimiza o desempenho, controlando ou modificando o padrão de fermentação ruminal. O objetivo do estudo buscou avaliar os efeitos da utilização de produtos à base de Saccharomyces cerevisiae durante mudanças na concentração de amido da dieta sobre a manutenção do pH ruminal, desempenho e metabolismo de ovinos confinados. Dessa forma, 20 fêmeas ovinas adultas mestiças das raças Texel e Corriedale (44,7±6,97 PV) foram divididas em três grupos: Controle (n=6), Cultron X (cultura de levedura; n=7) e Cultron Pro (levedura hidrolisada; n=7), administrados na dose de 5 g/ovelha/dia (10x1010ufc/g de MS). O experimento teve duração de 20 dias divididos em quatro períodos, alternando entre 40 e 60% de concentrado. Foram realizadas coletas de sangue e líquido ruminal ao final de cada período e mensuração da ingestão de